Tree Grid

The Tree Grid component displays hierarchical tabular data grouped in expandable nodes.

Tree Column
Rich Content
Programmatic Scrolling
Drag & Drop
Related Components

Tree Grid is a component for displaying hierarchical tabular data grouped into expandable nodes.

Source code

TreeGridBasic.javapackage com.vaadin.demo.component.treegrid;

import com.vaadin.demo.domain.DataService;
import com.vaadin.demo.domain.Person;
import com.vaadin.flow.component.html.Div;
import com.vaadin.flow.component.treegrid.TreeGrid;
import com.vaadin.flow.router.Route;

import java.util.List;

@Route("tree-grid-basic")
public class TreeGridBasic extends Div {

    private List<Person> managers = DataService.getManagers();

    public TreeGridBasic() {
        // tag::snippet[]
        TreeGrid<Person> treeGrid = new TreeGrid<>();
        treeGrid.setItems(managers, this::getStaff);
        treeGrid.addHierarchyColumn(Person::getFirstName)
                .setHeader("First name");
        treeGrid.addColumn(Person::getLastName).setHeader("Last name");
        treeGrid.addColumn(Person::getEmail).setHeader("Email");
        // end::snippet[]
        add(treeGrid);
    }

    public List<Person> getStaff(Person manager) {
        return DataService.getPeople(manager.getId());
    }

}
Person.javapackage com.vaadin.demo.domain;

import java.util.Date;

import jakarta.annotation.Nonnull;


// tag::snippet[]
public class Person {

    @Nonnull
    private String firstName;

    @Nonnull
    private String lastName;

    @Nonnull
    private String email;

    @Nonnull
    private Date birthday;

    @Nonnull
    private Integer id;

    @Nonnull
    private Boolean subscriber;

    @Nonnull
    private String membership;

    @Nonnull
    private String pictureUrl;

    @Nonnull
    private String profession;

    @Nonnull
    private Address address;

    private Integer managerId;

    @Nonnull
    private Boolean manager;

    @Nonnull
    private String status;

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    public String getFullName() {
        return firstName + " " + lastName;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    public boolean isSubscriber() {
        return subscriber;
    }

    public void setSubscriber(boolean subscriber) {
        this.subscriber = subscriber;
    }

    public String getMembership() {
        return membership;
    }

    public void setMembership(String membership) {
        this.membership = membership;
    }

    public String getPictureUrl() {
        return pictureUrl;
    }

    public void setPictureUrl(String pictureUrl) {
        this.pictureUrl = pictureUrl;
    }

    public String getProfession() {
        return profession;
    }

    public void setProfession(String profession) {
        this.profession = profession;
    }

    public Address getAddress() {
        return address;
    }

    public void setAddress(Address address) {
        this.address = address;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    @Override
    public int hashCode() {
        return id;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (!(obj instanceof Person)) {
            return false;
        }
        Person other = (Person) obj;
        return id == other.id;
    }

    public Integer getManagerId() {
        return managerId;
    }

    public void setManagerId(Integer managerId) {
        this.managerId = managerId;
    }

    public boolean isManager() {
        return manager;
    }

    public void setManager(boolean manager) {
        this.manager = manager;
    }

    public String getStatus() {
        return status;
    }

    public void setStatus(String status) {
        this.status = status;
    }
}
// end::snippet[]
tree-grid-basic.tsximport React from 'react';
import {
  Grid,
  type GridDataProviderCallback,
  type GridDataProviderParams,
} from '@vaadin/react-components/Grid.js';
import { GridColumn } from '@vaadin/react-components/GridColumn.js';
import { GridTreeColumn } from '@vaadin/react-components/GridTreeColumn.js';
import { getPeople } from 'Frontend/demo/domain/DataService';
import type Person from 'Frontend/generated/com/vaadin/demo/domain/Person';

// tag::snippet[]
async function dataProvider(
  params: GridDataProviderParams<Person>,
  callback: GridDataProviderCallback<Person>
) {
  // The requested page and the full length of the corresponding
  // hierarchy level is requested from the data service
  const { people, hierarchyLevelSize } = await getPeople({
    count: params.pageSize,
    startIndex: params.page * params.pageSize,
    managerId: params.parentItem ? params.parentItem.id : null,
  });

  callback(people, hierarchyLevelSize);
}

function Example() {
  return (
    <Grid itemHasChildrenPath="manager" dataProvider={dataProvider}>
      <GridTreeColumn path="firstName" />
      <GridColumn path="lastName" />
      <GridColumn path="email" />
    </Grid>
  );
}
// end::snippet[]

tree-grid-basic.tsimport '@vaadin/grid';
import '@vaadin/grid/vaadin-grid-tree-column.js';
import { html, LitElement } from 'lit';
import { customElement } from 'lit/decorators.js';
import type { GridDataProviderCallback, GridDataProviderParams } from '@vaadin/grid';
import { getPeople } from 'Frontend/demo/domain/DataService';
import { applyTheme } from 'Frontend/demo/theme';
import type Person from 'Frontend/generated/com/vaadin/demo/domain/Person';

@customElement('tree-grid-basic')
export class Example extends LitElement {
  protected override createRenderRoot() {
    const root = super.createRenderRoot();
    applyTheme(root);
    return root;
  }

  // tag::snippet[]
  async dataProvider(
    params: GridDataProviderParams<Person>,
    callback: GridDataProviderCallback<Person>
  ) {
    // The requested page and the full length of the corresponding
    // hierarchy level is requested from the data service
    const { people, hierarchyLevelSize } = await getPeople({
      count: params.pageSize,
      startIndex: params.page * params.pageSize,
      managerId: params.parentItem ? params.parentItem.id : null,
    });

    callback(people, hierarchyLevelSize);
  }

  protected override render() {
    return html`
      <vaadin-grid .itemHasChildrenPath="${'manager'}" .dataProvider="${this.dataProvider}">
        <vaadin-grid-tree-column path="firstName"></vaadin-grid-tree-column>
        <vaadin-grid-column path="lastName"></vaadin-grid-column>
        <vaadin-grid-column path="email"></vaadin-grid-column>
      </vaadin-grid>
    `;
  }
  // end::snippet[]
}

Tree Grid is an extension of the Grid component, so it inherits all of Grid’s features, including:

However, Tree Grid isn’t meant to be used as a navigation menu.

Tree Column

The tree column contains the toggles for expanding and collapsing nodes. Nodes are opened and closed by clicking a tree column’s cell. They can also be toggled programmatically.

Open in a
new tab

Source code

TreeGridColumn.javapackage com.vaadin.demo.component.treegrid;

import com.vaadin.demo.domain.DataService;
import com.vaadin.demo.domain.Person;
import com.vaadin.flow.component.button.Button;
import com.vaadin.flow.component.html.Div;
import com.vaadin.flow.component.html.H3;
import com.vaadin.flow.component.orderedlayout.FlexComponent;
import com.vaadin.flow.component.orderedlayout.HorizontalLayout;
import com.vaadin.flow.component.treegrid.TreeGrid;
import com.vaadin.flow.router.Route;

import java.util.List;

@Route("tree-grid-column")
public class TreeGridColumn extends Div {

    private List<Person> managers = DataService.getManagers();

    public TreeGridColumn() {
        TreeGrid<Person> treeGrid = new TreeGrid<>();
        treeGrid.setItems(managers, this::getStaff);
        treeGrid.addHierarchyColumn(Person::getFirstName)
                .setHeader("First name");
        treeGrid.addColumn(Person::getLastName).setHeader("Last name");
        treeGrid.addColumn(Person::getEmail).setHeader("Email");

        H3 employees = new H3("Employees");
        employees.getStyle().set("margin", "0");

        // tag::snippet[]
        Button expand = new Button("Expand All");
        expand.addClickListener(event -> treeGrid.expand(managers));

        Button collapse = new Button("Collapse All");
        collapse.addClickListener(event -> treeGrid.collapse(managers));
        // end::snippet[]

        HorizontalLayout header = new HorizontalLayout(employees, expand,
                collapse);
        header.setAlignItems(FlexComponent.Alignment.CENTER);
        header.setHeight("var(--lumo-space-xl)");
        header.setFlexGrow(1, employees);

        add(header, treeGrid);
    }

    public List<Person> getStaff(Person manager) {
        return DataService.getPeople(manager.getId());
    }

}
Person.javapackage com.vaadin.demo.domain;

import java.util.Date;

import jakarta.annotation.Nonnull;


// tag::snippet[]
public class Person {

    @Nonnull
    private String firstName;

    @Nonnull
    private String lastName;

    @Nonnull
    private String email;

    @Nonnull
    private Date birthday;

    @Nonnull
    private Integer id;

    @Nonnull
    private Boolean subscriber;

    @Nonnull
    private String membership;

    @Nonnull
    private String pictureUrl;

    @Nonnull
    private String profession;

    @Nonnull
    private Address address;

    private Integer managerId;

    @Nonnull
    private Boolean manager;

    @Nonnull
    private String status;

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    public String getFullName() {
        return firstName + " " + lastName;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    public boolean isSubscriber() {
        return subscriber;
    }

    public void setSubscriber(boolean subscriber) {
        this.subscriber = subscriber;
    }

    public String getMembership() {
        return membership;
    }

    public void setMembership(String membership) {
        this.membership = membership;
    }

    public String getPictureUrl() {
        return pictureUrl;
    }

    public void setPictureUrl(String pictureUrl) {
        this.pictureUrl = pictureUrl;
    }

    public String getProfession() {
        return profession;
    }

    public void setProfession(String profession) {
        this.profession = profession;
    }

    public Address getAddress() {
        return address;
    }

    public void setAddress(Address address) {
        this.address = address;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    @Override
    public int hashCode() {
        return id;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (!(obj instanceof Person)) {
            return false;
        }
        Person other = (Person) obj;
        return id == other.id;
    }

    public Integer getManagerId() {
        return managerId;
    }

    public void setManagerId(Integer managerId) {
        this.managerId = managerId;
    }

    public boolean isManager() {
        return manager;
    }

    public void setManager(boolean manager) {
        this.manager = manager;
    }

    public String getStatus() {
        return status;
    }

    public void setStatus(String status) {
        this.status = status;
    }
}
// end::snippet[]
tree-grid-column.tsximport React, { useMemo } from 'react';
import { useSignal } from '@vaadin/hilla-react-signals';
import { Button } from '@vaadin/react-components/Button.js';
import {
  Grid,
  type GridDataProviderCallback,
  type GridDataProviderParams,
} from '@vaadin/react-components/Grid.js';
import { GridColumn } from '@vaadin/react-components/GridColumn.js';
import { GridTreeColumn } from '@vaadin/react-components/GridTreeColumn.js';
import { HorizontalLayout } from '@vaadin/react-components/HorizontalLayout.js';
import { getPeople } from 'Frontend/demo/domain/DataService';
import type Person from 'Frontend/generated/com/vaadin/demo/domain/Person';

function Example() {
  const managers = useSignal<Person[]>([]);
  const expandedItems = useSignal<Person[]>([]);

  const dataProvider = useMemo(
    () =>
      async (
        params: GridDataProviderParams<Person>,
        callback: GridDataProviderCallback<Person>
      ) => {
        const { people, hierarchyLevelSize } = await getPeople({
          count: params.pageSize,
          startIndex: params.page * params.pageSize,
          managerId: params.parentItem ? params.parentItem.id : null,
        });

        if (!managers.value.length && !params.parentItem) {
          managers.value = people;
        }

        callback(people, hierarchyLevelSize);
      },
    []
  );

  const expandAll = () => {
    expandedItems.value = [...managers.value];
  };

  const collapseAll = () => {
    expandedItems.value = [];
  };

  return (
    <>
      {/* tag::snippet[] */}
      <HorizontalLayout style={{ alignItems: 'center', height: '3.5rem' }} theme="spacing">
        <h3 style={{ flexGrow: 1, margin: 0 }}>Employee</h3>
        <Button onClick={expandAll}>Expand All</Button>
        <Button onClick={collapseAll}>Collapse All</Button>
      </HorizontalLayout>

      <Grid
        dataProvider={dataProvider}
        itemIdPath="id"
        itemHasChildrenPath="manager"
        expandedItems={expandedItems.value}
      >
        <GridTreeColumn path="firstName" />
        <GridColumn path="lastName" />
        <GridColumn path="email" />
      </Grid>
      {/* end::snippet[] */}
    </>
  );
}

tree-grid-column.tsimport '@vaadin/button';
import '@vaadin/grid';
import '@vaadin/grid/vaadin-grid-tree-column.js';
import '@vaadin/horizontal-layout';
import { html, LitElement } from 'lit';
import { customElement, state } from 'lit/decorators.js';
import type { GridDataProviderCallback, GridDataProviderParams } from '@vaadin/grid';
import { getPeople } from 'Frontend/demo/domain/DataService';
import { applyTheme } from 'Frontend/demo/theme';
import type Person from 'Frontend/generated/com/vaadin/demo/domain/Person';

@customElement('tree-grid-column')
export class Example extends LitElement {
  protected override createRenderRoot() {
    const root = super.createRenderRoot();
    applyTheme(root);
    return root;
  }

  private managers: Person[] = [];

  private dataProvider = async (
    params: GridDataProviderParams<Person>,
    callback: GridDataProviderCallback<Person>
  ) => {
    const { people, hierarchyLevelSize } = await getPeople({
      count: params.pageSize,
      startIndex: params.page * params.pageSize,
      managerId: params.parentItem ? params.parentItem.id : null,
    });

    if (!params.parentItem) {
      this.managers = people;
    }

    callback(people, hierarchyLevelSize);
  };

  // tag::snippet[]
  @state()
  private expandedItems: unknown[] = [];

  protected override render() {
    return html`
      <vaadin-horizontal-layout style="align-items: center; height: 3.5rem;" theme="spacing">
        <h3 style="flex-grow: 1; margin: 0;">Employee</h3>
        <vaadin-button @click="${this.expandAll}">Expand All</vaadin-button>
        <vaadin-button @click="${this.collapseAll}">Collapse All</vaadin-button>
      </vaadin-horizontal-layout>

      <vaadin-grid
        .dataProvider="${this.dataProvider}"
        .itemIdPath="${'id'}"
        .itemHasChildrenPath="${'manager'}"
        .expandedItems="${this.expandedItems}"
      >
        <vaadin-grid-tree-column path="firstName"></vaadin-grid-tree-column>
        <vaadin-grid-column path="lastName"></vaadin-grid-column>
        <vaadin-grid-column path="email"></vaadin-grid-column>
      </vaadin-grid>
    `;
  }

  private expandAll() {
    this.expandedItems = [...this.managers];
  }

  private collapseAll() {
    this.expandedItems = [];
  }
  // end::snippet[]
}

Rich Content

Like Grid, Tree Grid supports rich content.

Open in a
new tab

Source code

TreeGridRichContent.javapackage com.vaadin.demo.component.treegrid;

import com.vaadin.demo.domain.DataService;
import com.vaadin.demo.domain.Person;
import com.vaadin.flow.component.avatar.Avatar;
import com.vaadin.flow.component.html.Anchor;
import com.vaadin.flow.component.html.Div;
import com.vaadin.flow.component.html.Span;
import com.vaadin.flow.component.icon.Icon;
import com.vaadin.flow.component.icon.VaadinIcon;
import com.vaadin.flow.component.orderedlayout.FlexComponent;
import com.vaadin.flow.component.orderedlayout.HorizontalLayout;
import com.vaadin.flow.component.orderedlayout.VerticalLayout;
import com.vaadin.flow.component.treegrid.TreeGrid;
import com.vaadin.flow.router.Route;

import java.util.List;

@Route("tree-grid-rich-content")
public class TreeGridRichContent extends Div {

    private List<Person> managers = DataService.getManagers();

    public TreeGridRichContent() {
        TreeGrid<Person> treeGrid = new TreeGrid<>();
        treeGrid.setItems(managers, this::getStaff);

        // tag::snippet[]
        treeGrid.addComponentHierarchyColumn(person -> {
            Avatar avatar = new Avatar();
            avatar.setName(person.getFullName());
            avatar.setImage(person.getPictureUrl());

            Span fullName = new Span(person.getFullName());

            Span profession = new Span(person.getProfession());
            profession.getStyle()
                    .set("color", "var(--lumo-secondary-text-color)")
                    .set("font-size", "0.875rem");

            VerticalLayout column = new VerticalLayout(fullName, profession);
            column.getStyle().set("line-height", "var(--lumo-line-height-m)");
            column.setPadding(false);
            column.setSpacing(false);

            HorizontalLayout row = new HorizontalLayout(avatar, column);
            row.setAlignItems(FlexComponent.Alignment.CENTER);
            row.setSpacing(true);
            return row;
        }).setHeader("Employee");

        treeGrid.addComponentColumn(person -> {
            Icon emailIcon = createIcon(VaadinIcon.ENVELOPE);
            Span email = new Span(person.getEmail());

            Anchor emailLink = new Anchor();
            emailLink.add(emailIcon, email);
            emailLink.setHref("mailto:" + person.getEmail());
            emailLink.getStyle().set("align-items", "center").set("display",
                    "flex");

            Icon phoneIcon = createIcon(VaadinIcon.PHONE);
            Span phone = new Span(person.getAddress().getPhone());

            Anchor phoneLink = new Anchor();
            phoneLink.add(phoneIcon, phone);
            phoneLink.setHref("tel:" + person.getAddress().getPhone());
            phoneLink.getStyle().set("align-items", "center").set("display",
                    "flex");

            VerticalLayout column = new VerticalLayout(emailLink, phoneLink);
            column.getStyle().set("font-size", "0.875rem").set("line-height",
                    "var(--lumo-line-height-m)");
            column.setPadding(false);
            column.setSpacing(false);
            return column;
        }).setHeader("Contact");
        // end::snippet[]

        add(treeGrid);
    }

    private Icon createIcon(VaadinIcon vaadinIcon) {
        Icon icon = vaadinIcon.create();
        icon.getStyle().set("margin-inline-end", "var(--lumo-space-s)");
        icon.setSize("var(--lumo-icon-size-s)");
        return icon;
    }

    public List<Person> getStaff(Person manager) {
        return DataService.getPeople(manager.getId());
    }

}
Person.javapackage com.vaadin.demo.domain;

import java.util.Date;

import jakarta.annotation.Nonnull;


// tag::snippet[]
public class Person {

    @Nonnull
    private String firstName;

    @Nonnull
    private String lastName;

    @Nonnull
    private String email;

    @Nonnull
    private Date birthday;

    @Nonnull
    private Integer id;

    @Nonnull
    private Boolean subscriber;

    @Nonnull
    private String membership;

    @Nonnull
    private String pictureUrl;

    @Nonnull
    private String profession;

    @Nonnull
    private Address address;

    private Integer managerId;

    @Nonnull
    private Boolean manager;

    @Nonnull
    private String status;

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    public String getFullName() {
        return firstName + " " + lastName;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    public boolean isSubscriber() {
        return subscriber;
    }

    public void setSubscriber(boolean subscriber) {
        this.subscriber = subscriber;
    }

    public String getMembership() {
        return membership;
    }

    public void setMembership(String membership) {
        this.membership = membership;
    }

    public String getPictureUrl() {
        return pictureUrl;
    }

    public void setPictureUrl(String pictureUrl) {
        this.pictureUrl = pictureUrl;
    }

    public String getProfession() {
        return profession;
    }

    public void setProfession(String profession) {
        this.profession = profession;
    }

    public Address getAddress() {
        return address;
    }

    public void setAddress(Address address) {
        this.address = address;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    @Override
    public int hashCode() {
        return id;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (!(obj instanceof Person)) {
            return false;
        }
        Person other = (Person) obj;
        return id == other.id;
    }

    public Integer getManagerId() {
        return managerId;
    }

    public void setManagerId(Integer managerId) {
        this.managerId = managerId;
    }

    public boolean isManager() {
        return manager;
    }

    public void setManager(boolean manager) {
        this.manager = manager;
    }

    public String getStatus() {
        return status;
    }

    public void setStatus(String status) {
        this.status = status;
    }
}
// end::snippet[]
tree-grid-rich-content.tsximport '@vaadin/icons';
import React, { useCallback } from 'react';
import { useSignal } from '@vaadin/hilla-react-signals';
import { Avatar } from '@vaadin/react-components/Avatar.js';
import {
  Grid,
  type GridDataProviderCallback,
  type GridDataProviderParams,
} from '@vaadin/react-components/Grid.js';
import { GridColumn } from '@vaadin/react-components/GridColumn.js';
import { GridTreeToggle } from '@vaadin/react-components/GridTreeToggle.js';
import { HorizontalLayout } from '@vaadin/react-components/HorizontalLayout.js';
import { Icon } from '@vaadin/react-components/Icon.js';
import { VerticalLayout } from '@vaadin/react-components/VerticalLayout.js';
import { getPeople } from 'Frontend/demo/domain/DataService';
import type Person from 'Frontend/generated/com/vaadin/demo/domain/Person';

async function dataProvider(
  params: GridDataProviderParams<Person>,
  callback: GridDataProviderCallback<Person>
) {
  const { people, hierarchyLevelSize } = await getPeople({
    count: params.pageSize,
    startIndex: params.page * params.pageSize,
    managerId: params.parentItem ? params.parentItem.id : null,
  });

  callback(people, hierarchyLevelSize);
}

function contactRenderer({ item: person }: { item: Person }) {
  return (
    <VerticalLayout
      style={{
        fontSize: 'var(--lumo-font-size-s)',
        lineHeight: 'var(--lumo-line-height-m)',
      }}
    >
      <a href={`mailto:${person.email}`} style={{ display: 'flex', alignItems: 'center' }}>
        <Icon
          icon="vaadin:envelope"
          style={{
            height: 'var(--lumo-icon-size-s)',
            marginInlineEnd: 'var(--lumo-space-s)',
            width: 'var(--lumo-icon-size-s)',
          }}
        />
        <span>{person.email}</span>
      </a>
      <a href={`tel:${person.address.phone}`} style={{ display: 'flex', alignItems: 'center' }}>
        <Icon
          icon="vaadin:phone"
          style={{
            height: 'var(--lumo-icon-size-s)',
            marginInlineEnd: 'var(--lumo-space-s)',
            width: 'var(--lumo-icon-size-s)',
          }}
        />
        <span>{person.address.phone}</span>
      </a>
    </VerticalLayout>
  );
}

function Example() {
  // tag::snippet[]
  const expandedItems = useSignal<Person[]>([]);

  const toggleRenderer = useCallback(
    ({ item: person, model }: { item: Person; model: { level?: number; expanded?: boolean } }) => (
      <GridTreeToggle
        leaf={!person.manager}
        level={model?.level ?? 0}
        expanded={!!model?.expanded}
        onClick={(e) => {
          if (!e.defaultPrevented) {
            return;
          }
          if (e.currentTarget.expanded) {
            expandedItems.value = [...expandedItems.value, person];
          } else {
            expandedItems.value = expandedItems.value.filter((p) => p.id !== person.id);
          }
        }}
      >
        <HorizontalLayout style={{ alignItems: 'center' }} theme="spacing">
          <Avatar img={person.pictureUrl} name={`${person.firstName} ${person.lastName}`} />
          <VerticalLayout style={{ lineHeight: 'var(--lumo-line-height-m)' }}>
            <span>
              {person.firstName} {person.lastName}
            </span>
            <span
              style={{
                fontSize: 'var(--lumo-font-size-s)',
                color: 'var(--lumo-secondary-text-color)',
              }}
            >
              {person.profession}
            </span>
          </VerticalLayout>
        </HorizontalLayout>
      </GridTreeToggle>
    ),
    []
  );

  return (
    <Grid dataProvider={dataProvider} expandedItems={expandedItems.value}>
      <GridColumn autoWidth header="Employee" renderer={toggleRenderer} />
      <GridColumn autoWidth header="Contact" renderer={contactRenderer} />
    </Grid>
  );
  // end::snippet[]
}

tree-grid-rich-content.tsimport '@vaadin/avatar';
import '@vaadin/button';
import '@vaadin/grid';
import '@vaadin/grid/vaadin-grid-tree-toggle.js';
import '@vaadin/horizontal-layout';
import '@vaadin/icon';
import '@vaadin/icons';
import '@vaadin/vertical-layout';
import { html, LitElement } from 'lit';
import { customElement, state } from 'lit/decorators.js';
import type { GridDataProviderCallback, GridDataProviderParams } from '@vaadin/grid';
import type { GridColumnBodyLitRenderer } from '@vaadin/grid/lit.js';
import { columnBodyRenderer } from '@vaadin/grid/lit.js';
import type { GridTreeToggleExpandedChangedEvent } from '@vaadin/grid/vaadin-grid-tree-toggle.js';
import { getPeople } from 'Frontend/demo/domain/DataService';
import { applyTheme } from 'Frontend/demo/theme';
import type Person from 'Frontend/generated/com/vaadin/demo/domain/Person';

@customElement('tree-grid-rich-content')
export class Example extends LitElement {
  protected override createRenderRoot() {
    const root = super.createRenderRoot();
    applyTheme(root);
    return root;
  }

  @state()
  private expandedItems: Person[] = [];

  async dataProvider(
    params: GridDataProviderParams<Person>,
    callback: GridDataProviderCallback<Person>
  ) {
    const { people, hierarchyLevelSize } = await getPeople({
      count: params.pageSize,
      startIndex: params.page * params.pageSize,
      managerId: params.parentItem ? params.parentItem.id : null,
    });

    callback(people, hierarchyLevelSize);
  }

  // tag::snippet[]
  private employeeRenderer: GridColumnBodyLitRenderer<Person> = (person, model) => html`
    <vaadin-grid-tree-toggle
      .leaf="${!person.manager}"
      .level="${model.level ?? 0}"
      @expanded-changed="${(e: GridTreeToggleExpandedChangedEvent) => {
        if (e.detail.value) {
          this.expandedItems = [...this.expandedItems, person];
        } else {
          this.expandedItems = this.expandedItems.filter((p) => p.id !== person.id);
        }
      }}"
      .expanded="${!!model.expanded}"
    >
      <vaadin-horizontal-layout style="align-items: center;" theme="spacing">
        <vaadin-avatar
          img="${person.pictureUrl}"
          name="${`${person.firstName} ${person.lastName}`}"
        ></vaadin-avatar>
        <vaadin-vertical-layout style="line-height: var(--lumo-line-height-m);">
          <span>${person.firstName} ${person.lastName}</span>
          <span
            style="font-size: var(--lumo-font-size-s); color: var(--lumo-secondary-text-color);"
          >
            ${person.profession}
          </span>
        </vaadin-vertical-layout>
      </vaadin-horizontal-layout>
    </vaadin-grid-tree-toggle>
  `;

  private contactRenderer: GridColumnBodyLitRenderer<Person> = (person) => html`
    <vaadin-vertical-layout
      style="font-size: var(--lumo-font-size-s); line-height: var(--lumo-line-height-m);"
    >
      <a href="mailto:${person.email}" style="align-items: center; display: flex;">
        <vaadin-icon
          icon="vaadin:envelope"
          style="height: var(--lumo-icon-size-s); margin-inline-end: var(--lumo-space-s); width: var(--lumo-icon-size-s);"
        ></vaadin-icon>
        <span>${person.email}</span>
      </a>
      <a href="tel:${person.address.phone}" style="align-items: center; display: flex;">
        <vaadin-icon
          icon="vaadin:phone"
          style="height: var(--lumo-icon-size-s); margin-inline-end: var(--lumo-space-s); width: var(--lumo-icon-size-s);"
        ></vaadin-icon>
        <span>${person.address.phone}</span>
      </a>
    </vaadin-vertical-layout>
  `;

  protected override render() {
    return html`
      <vaadin-grid .dataProvider="${this.dataProvider}" .expandedItems="${this.expandedItems}">
        <vaadin-grid-column
          auto-width
          header="Employee"
          ${columnBodyRenderer(this.employeeRenderer, [])}
        ></vaadin-grid-column>
        <vaadin-grid-column
          auto-width
          header="Contact"
          ${columnBodyRenderer(this.contactRenderer, [])}
        ></vaadin-grid-column>
      </vaadin-grid>
    `;
  }
  // end::snippet[]
}

Programmatic Scrolling

Tree Grid supports programmatic navigation to a specific item. This is particularly useful when dealing with large data sets. It saves users from having to scroll through potentially hundreds or thousands of rows.

Scrolling to Item By Reference Flow

In Flow, you can bring an item into view by passing its object reference to the scrollToItem(T item) method. This method expands all parent items leading to the specified item and then scrolls the Tree Grid to position that item at the top of the viewport. Scrolling is skipped if the item is already in the viewport and fully visible.

Open in a
new tab

Source code

TreeGridScrollToItem.javapackage com.vaadin.demo.component.treegrid;

import com.vaadin.demo.domain.DataService;
import com.vaadin.demo.domain.Person;
import com.vaadin.flow.component.html.Div;
import com.vaadin.flow.component.select.Select;
import com.vaadin.flow.component.treegrid.TreeGrid;
import com.vaadin.flow.data.provider.hierarchy.TreeData;
import com.vaadin.flow.data.provider.hierarchy.TreeDataProvider;
import com.vaadin.flow.router.Route;

import java.util.ArrayList;
import java.util.List;

@Route("tree-grid-scroll-to-item")
public class TreeGridScrollToItem extends Div {
    private final TreeGrid<Person> treeGrid = new TreeGrid<>();

    public TreeGridScrollToItem() {
        TreeData<Person> treeData = new TreeData<>();
        treeData.addItems(DataService.getManagers(),
                manager -> DataService.getPeople(manager.getId()));
        treeGrid.setDataProvider(new TreeDataProvider<>(treeData));
        treeGrid.addHierarchyColumn(Person::getFullName).setWidth("300px")
                .setFlexGrow(0).setHeader("Full name");
        treeGrid.addColumn(Person::getEmail).setHeader("Email");

        add(treeGrid);

        Select<Person> scrollToItem = new Select<>();
        scrollToItem.setLabel("Scroll to item");
        scrollToItem.setItemLabelGenerator(Person::getFullName);
        scrollToItem.setItems(getItemsToScrollTo());
        scrollToItem.setWidth("200px");
        scrollToItem.addValueChangeListener(event -> {
            Person item = event.getValue();
            // tag::snippet[]
            treeGrid.scrollToItem(item);
            // end::snippet[]
        });
        add(scrollToItem);
    }

    private List<Person> getItemsToScrollTo() {
        List<Person> itemsToScrollTo = new ArrayList<>();
        List<Person> managers = DataService.getManagers();
        Person middleRootItem = managers.get(managers.size() / 2);
        itemsToScrollTo.add(middleRootItem);
        List<Person> children = DataService.getPeople(middleRootItem.getId());
        while (!children.isEmpty()) {
            Person middleChild = children.get(children.size() / 2);
            itemsToScrollTo.add(middleChild);
            children = DataService.getPeople(middleChild.getId());
        }
        return itemsToScrollTo;
    }

}

This feature is available out of the box when using TreeDataProvider, a built-in data provider for connecting a TreeData structure to the Tree Grid.

Other data providers must implement two additional methods to support this feature:

HierarchicalDataProvider#getParent(T item)
HierarchicalDataProvider#getItemIndex(T item, HierarchicalQuery query)

You can find more information about using custom hierarchical data providers on the Data Binding page.

Scrolling to Item by Path

You can also scroll to an item by providing its hierarchical path – an array of indexes where each index refers to a child of the item at the previous index. For example, to scroll to the second child-row (index 1) of the third root-level row (index 2), you would provide the path 2, 1. Scrolling continues until it reaches the last index in the array or encounters a collapsed item.

Open in a
new tab

Source code

TreeGridScrollToIndex.javapackage com.vaadin.demo.component.treegrid;

import com.vaadin.demo.domain.DataService;
import com.vaadin.demo.domain.Person;
import com.vaadin.flow.component.button.Button;
import com.vaadin.flow.component.html.Div;
import com.vaadin.flow.component.orderedlayout.HorizontalLayout;
import com.vaadin.flow.component.orderedlayout.FlexComponent.Alignment;
import com.vaadin.flow.component.textfield.IntegerField;
import com.vaadin.flow.component.treegrid.TreeGrid;
import com.vaadin.flow.data.provider.hierarchy.AbstractHierarchicalDataProvider;
import com.vaadin.flow.data.provider.hierarchy.HierarchicalQuery;
import com.vaadin.flow.router.Route;

import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.stream.Stream;

import org.apache.commons.lang3.StringUtils;

@Route("tree-grid-scroll-to-index")
public class TreeGridScrollToIndex extends Div {

    private IntegerField parentIndexField = new IntegerField("Parent index");
    private IntegerField childIndexField = new IntegerField("Child index");
    private Button scrollToIndexButton = new Button();

    private Map<Person, List<Integer>> personToIndexAddress = new HashMap<>();
    private TreeGrid<Person> treeGrid = new TreeGrid<>();

    public TreeGridScrollToIndex() {
        treeGrid.setDataProvider(new LazyLoadingProvider());

        treeGrid.setUniqueKeyDataGenerator("key", (person) -> {
            return String.valueOf(person.getId());
        });

        treeGrid.expand(DataService.getManagers());

        treeGrid.addHierarchyColumn(Person::getFirstName).setWidth("200px")
                .setFlexGrow(0).setHeader("First name");

        treeGrid.addSelectionListener(e -> {
            if (e.getFirstSelectedItem().isPresent()) {
                Person person = e.getFirstSelectedItem().get();
                List<Integer> indexAddress = personToIndexAddress.get(person);
                if (indexAddress != null) {
                    parentIndexField.setValue(indexAddress.get(0));
                    if (indexAddress.size() > 1) {
                        childIndexField.setValue(indexAddress.get(1));
                    }
                }
            }
        });

        treeGrid.addColumn(person -> StringUtils
                .join(personToIndexAddress.get(person), ", ")).setWidth("80px")
                .setFlexGrow(0).setHeader("Index");
        treeGrid.addColumn(Person::getEmail).setHeader("Email");

        add(treeGrid);

        HorizontalLayout controls = new HorizontalLayout();
        controls.setSpacing(true);
        controls.setAlignItems(Alignment.END);

        parentIndexField.setWidth("120px");
        childIndexField.setWidth("120px");
        parentIndexField.setMin(0);
        childIndexField.setMin(0);
        parentIndexField.setStepButtonsVisible(true);
        childIndexField.setStepButtonsVisible(true);
        parentIndexField.setValue(13);
        childIndexField.setValue(6);
        parentIndexField.addValueChangeListener(e -> updateSelectedItem());
        childIndexField.addValueChangeListener(e -> updateSelectedItem());
        controls.add(parentIndexField);
        controls.add(childIndexField);

        scrollToIndexButton.addClickListener(e -> {
            int[] indexesToScrollTo = { parentIndexField.getValue(),
                    childIndexField.getValue() };
            // tag::snippet[]
            treeGrid.scrollToIndex(indexesToScrollTo);
            // end::snippet[]
        });
        controls.add(scrollToIndexButton);

        add(controls);
    }

    private void updateSelectedItem() {
        treeGrid.select(null);
        Integer parentIndex = parentIndexField.getValue();
        Integer childIndex = childIndexField.getValue();
        personToIndexAddress.entrySet().stream().filter(entry -> {
            List<Integer> indexes = entry.getValue();
            return indexes.size() == 2
                    && List.of(parentIndex, childIndex).equals(indexes);
        }).findFirst().ifPresent(entry -> {
            treeGrid.select(entry.getKey());
        });

        scrollToIndexButton
                .setText("Scroll to index: " + parentIndex + ", " + childIndex);
    }

    private class LazyLoadingProvider
            extends AbstractHierarchicalDataProvider<Person, Void> {

        @Override
        public int getChildCount(HierarchicalQuery<Person, Void> query) {
            return (int) this.fetchChildren(query).count();
        }

        @Override
        public Stream<Person> fetchChildren(
                HierarchicalQuery<Person, Void> query) {
            List<Person> people;
            if (query.getParent() == null) {
                people = DataService.getManagers();
            } else {
                people = DataService.getPeople(query.getParent().getId());
            }

            int limit = query.getLimit();
            int offset = query.getOffset();

            // Cache the index address of each person for demo purposes
            AtomicInteger personIndex = new AtomicInteger(0);
            people.stream().skip(offset).limit(limit).forEach(person -> {
                int index = offset + personIndex.getAndIncrement();
                List<Integer> parentIndexAddress = personToIndexAddress
                        .get(query.getParent());
                List<Integer> indexAddress = parentIndexAddress == null
                        ? List.of(index)
                        : List.of(parentIndexAddress.get(0), index);
                personToIndexAddress.put(person, indexAddress);
            });
            updateSelectedItem();

            return people.stream().skip(offset).limit(limit);
        }

        @Override
        public boolean hasChildren(Person item) {
            return DataService.getPeople(item.getId()).size() > 0;
        }

        @Override
        public boolean isInMemory() {
            return false;
        }
    }

}
tree-grid-scroll-to-index.tsximport React, { useMemo, useRef } from 'react';
import { useComputed, useSignal } from '@vaadin/hilla-react-signals';
import { Button } from '@vaadin/react-components/Button.js';
import {
  Grid,
  type GridDataProviderCallback,
  type GridDataProviderParams,
  type GridElement,
} from '@vaadin/react-components/Grid.js';
import { GridColumn } from '@vaadin/react-components/GridColumn.js';
import { GridTreeColumn } from '@vaadin/react-components/GridTreeColumn.js';
import { HorizontalLayout } from '@vaadin/react-components/HorizontalLayout.js';
import { IntegerField } from '@vaadin/react-components/IntegerField.js';
import { getPeople } from 'Frontend/demo/domain/DataService';
import type Person from 'Frontend/generated/com/vaadin/demo/domain/Person';

type PersonOrId =
  | Person
  | {
      id: number;
    };

function Example() {
  const gridRef = useRef<GridElement>(null);

  const idToIndexes = useMemo(() => new Map<number, number[]>(), []);

  const expandedItems = useSignal<Person[]>([]);
  const indexesToScrollTo = useSignal<number[]>([13, 6]);

  const indexesToScrollToRef = useRef<number[]>(indexesToScrollTo.value);
  indexesToScrollToRef.current = indexesToScrollTo.value;

  const dataProvider = useMemo(
    () =>
      async (
        params: GridDataProviderParams<PersonOrId>,
        callback: GridDataProviderCallback<PersonOrId>
      ) => {
        const startIndex = params.page * params.pageSize;
        const { people, hierarchyLevelSize } = await getPeople({
          count: params.pageSize,
          startIndex,
          managerId: params.parentItem ? params.parentItem.id : null,
        });

        // Cache the index address of each person for demo purposes
        people.forEach((person, idx) => {
          const index = startIndex + idx;
          const parentIndexes = params.parentItem
            ? (idToIndexes.get(params.parentItem.id) ?? [])
            : [];
          const indexAddress = [...parentIndexes, index];
          idToIndexes.set(person.id, indexAddress);

          if (
            indexAddress[0] === indexesToScrollToRef.current[0] &&
            indexAddress[1] === indexesToScrollToRef.current[1]
          ) {
            indexesToScrollTo.value = indexAddress;
          }
        });

        if (!expandedItems.value.length && !params.parentItem) {
          // Expand the root level by default
          expandedItems.value = people;
        }

        callback(people, hierarchyLevelSize);
      },
    []
  );

  const selectedItems = useComputed(() => {
    const indexAddress = indexesToScrollTo.value.join(', ');
    const id = Array.from(idToIndexes.entries()).find(
      ([, indexes]) => indexes.join(', ') === indexAddress
    )?.[0];
    return id ? [{ id }] : [];
  });

  return (
    <>
      <Grid
        ref={gridRef}
        itemIdPath="id"
        itemHasChildrenPath="manager"
        dataProvider={dataProvider}
        expandedItems={expandedItems.value}
        selectedItems={selectedItems.value}
        onActiveItemChanged={(e) => {
          if (e.detail.value) {
            indexesToScrollTo.value = idToIndexes.get(e.detail.value.id) ?? [];
          }
        }}
      >
        <GridTreeColumn<Person> path="firstName" width="200px" flexGrow={0} />
        <GridColumn<Person> header="Index" width="80px" flexGrow={0}>
          {({ item }) => idToIndexes.get(item.id)?.join(', ')}
        </GridColumn>
        <GridColumn<Person> path="email" />
      </Grid>

      <HorizontalLayout theme="spacing" style={{ alignItems: 'flex-end' }}>
        <IntegerField
          label="Parent index"
          stepButtonsVisible
          min={0}
          style={{ width: '120px' }}
          value={String(indexesToScrollTo.value[0])}
          onChange={(e) => {
            indexesToScrollTo.value = [parseInt(e.target.value) || 0, indexesToScrollTo.value[1]];
          }}
        />

        <IntegerField
          label="Child index"
          stepButtonsVisible
          min={0}
          style={{ width: '120px' }}
          value={String(indexesToScrollTo.value[1])}
          onChange={(e) => {
            indexesToScrollTo.value = [indexesToScrollTo.value[0], parseInt(e.target.value) || 0];
          }}
        />

        <Button
          onClick={() => {
            const grid = gridRef.current;
            if (grid) {
              // tag::snippet[]
              grid.scrollToIndex(...indexesToScrollTo.value);
              // end::snippet[]
            }
          }}
        >
          Scroll to index: {indexesToScrollTo.value.join(', ')}
        </Button>
      </HorizontalLayout>
    </>
  );
}

tree-grid-scroll-to-index.tsimport '@vaadin/button';
import '@vaadin/grid';
import '@vaadin/grid/vaadin-grid-tree-column.js';
import '@vaadin/horizontal-layout';
import '@vaadin/integer-field';
import { html, LitElement } from 'lit';
import { customElement, query, state } from 'lit/decorators.js';
import type {
  Grid,
  GridActiveItemChangedEvent,
  GridBodyRenderer,
  GridDataProviderCallback,
  GridDataProviderParams,
} from '@vaadin/grid';
import type { IntegerFieldChangeEvent } from '@vaadin/integer-field';
import { getPeople } from 'Frontend/demo/domain/DataService';
import { applyTheme } from 'Frontend/demo/theme';
import type Person from 'Frontend/generated/com/vaadin/demo/domain/Person';

@customElement('tree-grid-scroll-to-index')
export class Example extends LitElement {
  protected override createRenderRoot() {
    const root = super.createRenderRoot();
    applyTheme(root);
    return root;
  }

  @query('vaadin-grid')
  private grid!: Grid<Person>;

  @state()
  private expandedItems?: Person[];

  @state()
  private indexesToScrollTo: number[] = [13, 6];

  @state()
  private idToIndexes = new Map<number, number[]>();

  constructor() {
    super();
    this.dataProvider = this.dataProvider.bind(this);
  }

  async dataProvider(
    params: GridDataProviderParams<Person>,
    callback: GridDataProviderCallback<Person>
  ) {
    const startIndex = params.page * params.pageSize;
    const { people, hierarchyLevelSize } = await getPeople({
      count: params.pageSize,
      startIndex,
      managerId: params.parentItem ? params.parentItem.id : null,
    });

    // Cache the index address of each person for demo purposes
    people.forEach((person, idx) => {
      const index = startIndex + idx;
      const parentIndexes = params.parentItem
        ? (this.idToIndexes.get(params.parentItem.id) ?? [])
        : [];
      const indexes = [...parentIndexes, index];
      this.idToIndexes = new Map(this.idToIndexes).set(person.id, indexes);
    });

    if (!this.expandedItems && !params.parentItem) {
      // Expand the root level by default
      this.expandedItems = people;
    }

    callback(people, hierarchyLevelSize);
  }

  private indexRenderer: GridBodyRenderer<Person> = (root, _, { item }) => {
    root.textContent = this.idToIndexes.get(item.id)?.join(', ') ?? '';
  };

  private getSelectedItems(indexes: number[], idToIndexes: Map<number, number[]>) {
    const id = Array.from(idToIndexes.entries()).find(
      ([, idxs]) => idxs[0] === indexes[0] && idxs[1] === indexes[1]
    )?.[0];

    return id ? [{ id }] : [];
  }

  protected override render() {
    return html`
      <vaadin-grid
        item-id-path="id"
        item-has-children-path="manager"
        .dataProvider="${this.dataProvider}"
        .expandedItems="${this.expandedItems ?? []}"
        .selectedItems="${this.getSelectedItems(this.indexesToScrollTo, this.idToIndexes)}"
        @active-item-changed=${(e: GridActiveItemChangedEvent<Person>) => {
          if (e.detail.value) {
            this.indexesToScrollTo = this.idToIndexes.get(e.detail.value.id) ?? [];
          }
        }}
      >
        <vaadin-grid-tree-column
          path="firstName"
          width="200px"
          flex-grow="0"
        ></vaadin-grid-tree-column>

        <vaadin-grid-column
          header="Index"
          .renderer=${this.indexRenderer}
          width="80px"
          flex-grow="0"
        ></vaadin-grid-column>

        <vaadin-grid-column path="email"></vaadin-grid-column>
      </vaadin-grid>

      <vaadin-horizontal-layout theme="spacing" style="align-items: flex-end">
        <vaadin-integer-field
          label="Parent index"
          step-buttons-visible
          min="0"
          style="width: 120px"
          .value=${String(this.indexesToScrollTo[0] ?? '')}
          @change=${(e: IntegerFieldChangeEvent) => {
            this.indexesToScrollTo = [parseInt(e.target.value) || 0, this.indexesToScrollTo[1]];
          }}
        ></vaadin-integer-field>

        <vaadin-integer-field
          label="Child index"
          step-buttons-visible
          min="0"
          style="width: 120px"
          .value=${String(this.indexesToScrollTo[1] ?? '')}
          @change=${(e: IntegerFieldChangeEvent) => {
            this.indexesToScrollTo = [this.indexesToScrollTo[0], parseInt(e.target.value) || 0];
          }}
        ></vaadin-integer-field>

        <vaadin-button
          @click=${() => {
            // tag::snippet[]
            this.grid.scrollToIndex(...this.indexesToScrollTo);
            // end::snippet[]
          }}
        >
          Scroll to index: ${this.indexesToScrollTo.join(', ')}
        </vaadin-button>
      </vaadin-horizontal-layout>
    `;
  }
}

Drag & Drop

Tree Grid supports drag-and-drop operations. You can enable and handle them in your logic, for example, to allow users to move rows from one parent node to another:

Open in a
new tab

Source code

TreeGridDragDrop.javapackage com.vaadin.demo.component.treegrid;

import com.vaadin.demo.domain.DataService;
import com.vaadin.demo.domain.Person;
import com.vaadin.flow.component.grid.dnd.GridDropMode;
import com.vaadin.flow.component.html.Div;
import com.vaadin.flow.component.treegrid.TreeGrid;
import com.vaadin.flow.data.provider.hierarchy.TreeData;
import com.vaadin.flow.data.provider.hierarchy.TreeDataProvider;
import com.vaadin.flow.data.provider.hierarchy.HierarchicalDataProvider.HierarchyFormat;
import com.vaadin.flow.router.Route;

import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

@Route("tree-grid-drag-drop")
public class TreeGridDragDrop extends Div {

    private final List<Person> people = DataService.getPeople();
    private final List<Person> managers = people.stream()
            .filter(Person::isManager).toList();
    private final Map<Integer, List<Person>> staffByManagerId = people.stream()
            .filter(person -> person.getManagerId() != null)
            .collect(Collectors.groupingBy(Person::getManagerId));

    private Person draggedItem;

    public TreeGridDragDrop() {
        // tag::snippet[]
        TreeGrid<Person> treeGrid = setupTreeGrid();
        TreeData<Person> treeData = new TreeData<>();
        treeData.addItems(managers, this::getStaffByManager);

        // To preserve scroll position after refreshAll(), configure
        // TreeDataProvider to return data in the flattened hierarchy format.
        // More details can be found in the JavaDoc of the HierarchyFormat enum.
        TreeDataProvider<Person> treeDataProvider = new TreeDataProvider<>(
                treeData, HierarchyFormat.FLATTENED);
        treeGrid.setDataProvider(treeDataProvider);

        // Enable drag and drop
        treeGrid.setRowsDraggable(true);

        // Set a filter to allow dragging staff only
        treeGrid.setDragFilter(person -> !person.isManager());

        treeGrid.addDragStartListener(e -> {
            draggedItem = e.getDraggedItems().get(0);

            // Allow dropping on top of rows only
            treeGrid.setDropMode(GridDropMode.ON_TOP);

            // Set a filter to define valid drop targets
            treeGrid.setDropFilter(person ->
                    // Allow dropping on supervisors only
                    person.isManager() &&
                    // Disallow dropping on the same manager
                    !person.getId().equals(draggedItem.getManagerId()));
        });

        treeGrid.addDropListener(e -> {
            Person newManager = e.getDropTargetItem().orElse(null);
            if (newManager == null) {
                return;
            }

            draggedItem.setManagerId(newManager.getId());
            treeData.setParent(draggedItem, newManager);

            // Reset TreeGrid's cache to reflect the hierarchy changes in the UI
            treeDataProvider.refreshAll();
        });

        treeGrid.addDragEndListener(e -> {
            draggedItem = null;

            treeGrid.setDropMode(null);
            treeGrid.setDropFilter(null);
        });
        // end::snippet[]

        add(treeGrid);
    }

    private static TreeGrid<Person> setupTreeGrid() {
        TreeGrid<Person> treeGrid = new TreeGrid<>();
        treeGrid.addHierarchyColumn(Person::getFirstName)
                .setHeader("First name");
        treeGrid.addColumn(Person::getLastName).setHeader("Last name");
        treeGrid.addColumn(Person::getEmail).setHeader("Email");

        return treeGrid;
    }

    private List<Person> getStaffByManager(Person manager) {
        return staffByManagerId.getOrDefault(manager.getId(),
                Collections.emptyList());
    }

}
tree-grid-drag-drop.tsximport React, { useEffect, useMemo } from 'react';
import { useSignal } from '@vaadin/hilla-react-signals';
import {
  Grid,
  type GridDataProviderCallback,
  type GridDataProviderParams,
} from '@vaadin/react-components/Grid.js';
import { GridColumn } from '@vaadin/react-components/GridColumn.js';
import { GridTreeColumn } from '@vaadin/react-components/GridTreeColumn.js';
import { getPeople } from 'Frontend/demo/domain/DataService';
import type Person from 'Frontend/generated/com/vaadin/demo/domain/Person';

function Example() {
  // tag::snippet[]
  const draggedItem = useSignal<Person | undefined>(undefined);
  const items = useSignal<Person[]>([]);
  const expandedItems = useSignal<Person[]>([]);

  useEffect(() => {
    getPeople().then(({ people }) => {
      items.value = people;
    });
  }, []);

  const dataProvider = useMemo(
    () => (params: GridDataProviderParams<Person>, callback: GridDataProviderCallback<Person>) => {
      const { page, pageSize, parentItem } = params;
      const startIndex = page * pageSize;
      const endIndex = startIndex + pageSize;

      /*
    We cannot change the underlying data in this demo so this dataProvider uses
    a local field to fetch its values. This allows us to keep a reference to the
    modified list instead of loading a new list every time the dataProvider gets
    called. In a real application, you should always access your data source
    here and avoid using grid.clearCache() whenever possible.
    */
      const result = parentItem
        ? items.value.filter((item) => item.managerId === parentItem.id)
        : items.value.filter((item) => item.manager).slice(startIndex, endIndex);

      callback(result, result.length);
    },
    [items.value]
  );

  return (
    <Grid
      dataProvider={dataProvider}
      itemIdPath="id"
      itemHasChildrenPath="manager"
      expandedItems={expandedItems.value}
      onExpandedItemsChanged={(event) => {
        expandedItems.value = event.detail.value;
      }}
      rowsDraggable
      onGridDragstart={(event) => {
        draggedItem.value = event.detail.draggedItems[0];
      }}
      onGridDragend={() => {
        draggedItem.value = undefined;
      }}
      onGridDrop={(event) => {
        const manager = event.detail.dropTargetItem;
        if (draggedItem.value) {
          draggedItem.value.managerId = manager.id;
          items.value = [...items.value];
        }
      }}
      dropMode={draggedItem.value ? 'on-top' : undefined}
      dragFilter={(model) => {
        const { item } = model;
        return !item.manager; // Only drag non-managers
      }}
      dropFilter={(model) => {
        const { item } = model;
        return (
          item.manager && // Can only drop on a supervisor
          item.id !== draggedItem.value?.managerId // Disallow dropping on the same manager
        );
      }}
    >
      <GridTreeColumn path="firstName" />
      <GridColumn path="lastName" />
      <GridColumn path="email" />
    </Grid>
  );
  // end::snippet[]
}

tree-grid-drag-drop.tsimport '@vaadin/grid';
import '@vaadin/grid/vaadin-grid-tree-column.js';
import { html, LitElement } from 'lit';
import { customElement, query, state } from 'lit/decorators.js';
import type {
  Grid,
  GridDataProviderCallback,
  GridDataProviderParams,
  GridDragStartEvent,
  GridDropEvent,
  GridExpandedItemsChangedEvent,
  GridItemModel,
} from '@vaadin/grid';
import { getPeople } from 'Frontend/demo/domain/DataService';
import { applyTheme } from 'Frontend/demo/theme';
import type Person from 'Frontend/generated/com/vaadin/demo/domain/Person';

// tag::snippet[]
@customElement('tree-grid-drag-drop')
export class Example extends LitElement {
  protected override createRenderRoot() {
    const root = super.createRenderRoot();
    // Apply custom theme (only supported if your app uses one)
    applyTheme(root);
    return root;
  }

  @query('vaadin-grid')
  private grid!: Grid<Person>;

  @state()
  private draggedItem: Person | undefined;

  @state()
  private items: Person[] = [];

  @state()
  private managers: Person[] = [];

  @state()
  private expandedItems: Person[] = [];

  protected override async firstUpdated() {
    const { people } = await getPeople();
    this.items = people;
    this.managers = this.items.filter((item) => item.manager);
    // Avoid using this method
    this.grid.clearCache();
  }

  private dataProvider = (
    params: GridDataProviderParams<Person>,
    callback: GridDataProviderCallback<Person>
  ) => {
    const { page, pageSize, parentItem } = params;
    const startIndex = page * pageSize;
    const endIndex = startIndex + pageSize;

    /*
    We cannot change the underlying data in this demo so this dataProvider uses
    a local field to fetch its values. This allows us to keep a reference to the
    modified list instead of loading a new list every time the dataProvider gets
    called. In a real application, you should always access your data source
    here and avoid using grid.clearCache() whenever possible.
    */
    const result = parentItem
      ? this.items.filter((item) => item.managerId === parentItem.id)
      : this.managers.slice(startIndex, endIndex);

    callback(result, result.length);
  };

  protected override render() {
    return html`
      <vaadin-grid
        .dataProvider="${this.dataProvider}"
        item-id-path="id"
        item-has-children-path="manager"
        .expandedItems="${this.expandedItems}"
        @expanded-items-changed="${(event: GridExpandedItemsChangedEvent<Person>) => {
          this.expandedItems = event.detail.value;
        }}"
        rows-draggable
        @grid-dragstart="${(event: GridDragStartEvent<Person>) => {
          this.draggedItem = event.detail.draggedItems[0];
        }}"
        @grid-dragend="${() => {
          this.draggedItem = undefined;
        }}"
        @grid-drop="${(event: GridDropEvent<Person>) => {
          const manager = event.detail.dropTargetItem;
          if (this.draggedItem) {
            // In a real application, when using a data provider, you should
            // change the persisted data instead of updating a field
            this.draggedItem.managerId = manager.id;
            // Avoid using this method
            this.grid.clearCache();
          }
        }}"
        .dropMode="${this.draggedItem ? 'on-top' : undefined}"
        .dragFilter="${(model: GridItemModel<Person>) => {
          const { item } = model;
          return !item.manager; // Only drag non-managers
        }}"
        .dropFilter="${(model: GridItemModel<Person>) => {
          const { item } = model;
          return (
            item.manager && // Can only drop on a supervisor
            item.id !== this.draggedItem?.managerId // Disallow dropping on the same manager
          );
        }}"
      >
        <vaadin-grid-tree-column path="firstName"></vaadin-grid-tree-column>
        <vaadin-grid-column path="lastName"></vaadin-grid-column>
        <vaadin-grid-column path="email"></vaadin-grid-column>
      </vaadin-grid>
    `;
  }
}
// end::snippet[]

For more drag-and-drop examples and API references, refer to the Grid’s Drag and Drop documentation.

Note

In Flow, Tree Grid drag-and-drop works best with data providers that use the flattened hierarchy format. This format gives more predictable scrolling and allows Tree Grid to maintain its scroll position after hierarchy changes. For more details on this and other supported formats, see the Hierarchy Formats section on the Data Binding page.

Component	Usage Recommendation
Grid	Component for showing tabular data.
Grid Pro	Component for showing and editing tabular data.
CRUD	Component for creating, displaying, updating, and deleting tabular data.

Component

Usage Recommendation

Grid

Component for showing tabular data.

Grid Pro

Component for showing and editing tabular data.

CRUD

Component for creating, displaying, updating, and deleting tabular data.

9DEF736F-975A-469A-8625-A0A6E086BF50

Docs

Docs

Tree Grid

Tree Column

Rich Content

Programmatic Scrolling

Scrolling to Item By Reference Flow

Scrolling to Item by Path

Drag & Drop

Docs

Tree Column

Rich Content

Programmatic Scrolling

Scrolling to Item By Reference Flow

Scrolling to Item by Path

Drag & Drop

Related Components