Context menu in Angular Diagram component

26 Oct 202424 minutes to read

In a graphical user interface (GUI), a context menu is a type of menu that appears when you perform a right-click operation. It offers users a set of actions relevant to the current context. In diagrams, context menus can be customized extensively. The Diagram control provides built-in context menu items while also allowing users to define custom menu items through thecontextMenuSettings property. This flexibility enables tailoring menus to specific application needs, including creating nested levels of menu items for more intricate user interactions.

NOTE

If you want to use contextMenu in diagram, you need to inject DiagramContextMenu Module in the diagram.

Diagram provides some default context menu items to ease the execution of some frequently used commands. The show property helps you to enable/disable the context menu.

The following code illustrates how to enable the default context menu items.

app.component.ts
main.ts
import { Component, ViewEncapsulation, OnInit, ViewChild } from '@angular/core';
import { DiagramModule, DiagramContextMenuService, DiagramComponent, ShapeStyleModel } from '@syncfusion/ej2-angular-diagrams';
import { ContextMenuSettingsModel } from '@syncfusion/ej2-diagrams';

@Component({
imports: [
         DiagramModule
    ],

providers: [DiagramContextMenuService],
standalone: true,
    selector: "app-container",
    template: `<ejs-diagram #diagram id="diagram" width="100%" height="580px"[contextMenuSettings]="contextMenuSettings">
        <e-nodes>
            <e-node id='node1' [offsetX]=100 [offsetY]=100 [width]=100 [height]=100>
                <e-node-annotations>
                    <e-node-annotation id="label1" content="Rectangle1">
                    </e-node-annotation>
                </e-node-annotations>
            </e-node>
            <e-node id='node2' [offsetX]=300 [offsetY]=100 [width]=100 [height]=100>
                <e-node-annotations>
                    <e-node-annotation id="label1" content="Rectangle2">
                    </e-node-annotation>
                </e-node-annotations>
            </e-node>
        </e-nodes>
        <e-connectors>
            <e-connector id='connector1' type='Straight' sourceID='node1' targetID='node2'>
            </e-connector>
        </e-connectors>
    </ejs-diagram>`,
    encapsulation: ViewEncapsulation.None
})
export class AppComponent {
    @ViewChild("diagram")
    public diagram?: DiagramComponent;
    public contextMenuSettings?: ContextMenuSettingsModel
    ngOnInit(): void {
        //Enables the context menu
        this.contextMenuSettings = {
            show: true,
        }
    }
}
import { bootstrapApplication } from '@angular/platform-browser';
import { AppComponent } from './app.component';
import 'zone.js';
bootstrapApplication(AppComponent).catch((err) => console.error(err));

Context menus can be customized for individual nodes by defining specific menu items beyond the default options. To add additional context menu items, you need to define and incorporate them into the items property of the context menu.

Each custom item can be defined with specific text and ID using the text and ID properties, respectively. Additionally, you can enhance visual cues by associating icons through the iconCss for enabling the use of font icons. The target property specifies where each menu item should appear, and separators can be included using the separator property to visually group menu items. This flexibility allows for a tailored user interface that meets specific application needs efficiently. Nested menu items are defined within the items property of a parent menu item.

To display the custom context menu items alone, set the showCustomMenuOnlyproperty to true.

Upon clicking custom menu items, actions are handled using the contextMenuClick event in the diagram. This event allows you to define actions based on which menu item is clicked. For instance, in the example below, the cloning of nodes and the change of fill color for nodes and annotations are efficiently managed and implemented through this event.

The following code illustrates context menu click.

app.component.ts
main.ts
import { DiagramModule, DiagramContextMenuService, DiagramComponent } from '@syncfusion/ej2-angular-diagrams'
import {Component, ViewEncapsulation, OnInit, ViewChild } from '@angular/core';
import { ContextMenuSettingsModel } from '@syncfusion/ej2-diagrams';
import { MenuEventArgs } from '@syncfusion/ej2-navigations';

@Component({
imports: [
         DiagramModule
    ],

providers: [DiagramContextMenuService],
standalone: true,
    selector: "app-container",
    template: `<ejs-diagram #diagram id="diagram" width="100%" height="580px" [contextMenuSettings]="contextMenuSettings" (contextMenuClick)="contextMenuClick($event)">
        <e-nodes>
            <e-node id='node1' [offsetX]=100 [offsetY]=100 [width]=100 [height]=100 >
                <e-node-annotations>
                    <e-node-annotation id="label1" content="Rectangle1" >
                    </e-node-annotation>
                </e-node-annotations>
            </e-node>
            <e-node id='node2' [offsetX]=350 [offsetY]=150 [width]=100 [height]=100>
                <e-node-annotations>
                    <e-node-annotation id="label1" content="Rectangle2">
                    </e-node-annotation>
                </e-node-annotations>
            </e-node>
        </e-nodes>
    </ejs-diagram>`,
    encapsulation: ViewEncapsulation.None
})
export class AppComponent {
    @ViewChild("diagram")
    public diagram?: DiagramComponent;
    public contextMenuSettings?: ContextMenuSettingsModel;

    ngOnInit(): void {

        //Enables the context menu
        this.contextMenuSettings = {
            //Enables the context menu
            show: true,
            // Defines the custom context menu items
            items: [{
                // Text to be displayed
                text: 'Fill',
                items: [
                  { id: 'red', text: 'Red' },
                  { id: 'yellow', text: 'Yellow' },
                  { id: 'green', text: 'Green' },
                  { id: 'blue', text: 'Blue' },
                ],
                //Sets the id for the item
                id: 'fill',
                target: '.e-elementcontent',
                // Sets the css icons for the item
                iconCss: 'e-icons e-paint-bucket',
              },
              {
                text: 'Annotation color',
                id: 'annotationColor',
                items: [
                  { id: 'pink', text: 'Pink' },
                  { id: 'orange', text: 'Orange' },
                  { id: 'violet', text: 'Violet' },
                  { id: 'brown', text: 'Brown' },
                ],
                target: '.e-elementcontent',
                iconCss: 'e-icons e-font-color',
              },
              {
                text: 'Clone',
                id: 'clone',
                target: '.e-elementcontent',
                iconCss: 'e-icons e-copy',
              },
            ],
            // Hides the default context menu items
          showCustomMenuOnly: true,
        }
    }

    public contextMenuClick(args: MenuEventArgs): void {
        let selectedNode = (this.diagram as any).selectedItems.nodes[0];
        if (selectedNode && args.item.id !== 'fill' &&  args.item.id !== 'annotationColor') {
            if (
              args.item.text === 'Red' ||
              args.item.text === 'Blue' ||
              args.item.text === 'Yellow' ||
              args.item.text === 'Green'
            ) {
              selectedNode.style.fill = args.item.text;
              (this.diagram as any).dataBind();
            } else if (
              args.item.text === 'Pink' ||
              args.item.text === 'Violet' ||
              args.item.text === 'Orange' ||
              args.item.text === 'Brown'
            ) {
              selectedNode.annotations[0].style.fill = args.item.text;
              (this.diagram as any).dataBind();
            } else {
                (this.diagram as any).copy();
              (this.diagram as any).paste();
            }
        }

    }
    
}
import { bootstrapApplication } from '@angular/platform-browser';
import { AppComponent } from './app.component';
import 'zone.js';
bootstrapApplication(AppComponent).catch((err) => console.error(err));

In certain situations, you may want to hide specific menu items based on the selected elements in the diagram. This can be achieved using the contextMenuOpen event. When the context menu is opened via right-click, the contextMenuOpen event is triggered. Within this event, you can create an array of menu items to hide for the selected element and pass it to the hiddenItems property of the contextMenuOpen event argument.

The following example demonstrates how to display different custom menu items for nodes, connectors, and the diagram based on the selection.

app.component.ts
main.ts
import {Component, ViewEncapsulation, OnInit, ViewChild } from '@angular/core';
import { DiagramModule, DiagramContextMenuService, DiagramComponent} from '@syncfusion/ej2-angular-diagrams'
import { MenuEventArgs } from '@syncfusion/ej2-navigations';
import { ContextMenuSettingsModel,DiagramBeforeMenuOpenEventArgs} from '@syncfusion/ej2-diagrams';

@Component({
imports: [
         DiagramModule
    ],

providers: [DiagramContextMenuService],
standalone: true,
    selector: "app-container",
    template: `<ejs-diagram #diagram id="diagram" width="100%" height="580px" [contextMenuSettings]="contextMenuSettings" (contextMenuOpen)="contextMenuOpen($event)" (contextMenuClick)="contextMenuClick($event)">
        <e-nodes>
            <e-node id='node1' [offsetX]=100 [offsetY]=100 [width]=100 [height]=100 >
                <e-node-annotations>
                    <e-node-annotation id="label1" content="Rectangle1">
                    </e-node-annotation>
                </e-node-annotations>
            </e-node>
            <e-node id='node2' [offsetX]=300 [offsetY]=100 [width]=100 [height]=100 >
                <e-node-annotations>
                    <e-node-annotation id="label1" content="Rectangle2">
                    </e-node-annotation>
                </e-node-annotations>
            </e-node>
        </e-nodes>
        <e-connectors>
            <e-connector id='connector1' type='Straight' sourceID='node1' targetID='node2'>
            </e-connector>
        </e-connectors>
    </ejs-diagram>`,
    encapsulation: ViewEncapsulation.None
})
export class AppComponent {
    @ViewChild("diagram")
    public diagram?: DiagramComponent;
    public contextMenuSettings?: ContextMenuSettingsModel;

    ngOnInit(): void {
        //Enables the context menu
        this.contextMenuSettings = {
            show: true,
            items: [
                {
                  text: 'Change fill',
                  id: 'applyFill',
                  target: '.e-diagramcontent',
                  iconCss: 'e-icons e-paint-bucket',
                },
                {
                  text: 'Change stroke',
                  id: 'applyStroke',
                  target: '.e-diagramcontent',
                  iconCss: 'e-icons e-edit',
                },
                {
                  text: 'Select All',
                  id: 'selectAll',
                  target: '.e-diagramcontent',
                },
            ],
            // Hides the default context menu items
            showCustomMenuOnly: true,
        }
    }
    public contextMenuOpen(args: DiagramBeforeMenuOpenEventArgs): void {
        let hiddenItems = [];
        let selectedNode = (this.diagram as any).selectedItems.nodes[0];
        let selectedConnector = (this.diagram as any).selectedItems.connectors[0];
        if (selectedNode || selectedConnector) {
            hiddenItems.push('selectAll');
        } else {
        hiddenItems = ['applyFill', 'applyStroke'];
        }
        args.hiddenItems = hiddenItems
    }
      
    public contextMenuClick(args: MenuEventArgs): void {
        let selectedNode = (this.diagram as any).selectedItems.nodes[0];
        let selectedConnector = (this.diagram as any).selectedItems.connectors[0];
        if (selectedNode || selectedConnector) {
            if (selectedNode) {
                if (args.item.id === 'applyFill') {
                  selectedNode.style.fill =
                    selectedNode.style.fill === '#6BA5D7' ? 'green' : '#6BA5D7';
                } else if (args.item.id === 'applyStroke') {
                  selectedNode.style.strokeColor =
                    selectedNode.style.strokeColor === 'black' ? 'yellow' : 'black';
                }
            }
            if (selectedConnector) {
                if (args.item.id === 'applyFill') {
                  selectedConnector.targetDecorator.style.fill =
                    selectedConnector.targetDecorator.style.fill === 'yellow'? 'black': 'yellow';
                }
                selectedConnector.style.strokeColor =
                  selectedConnector.style.strokeColor === 'black' ? 'yellow': 'black';
                } 
        } else {
            (this.diagram as any).selectAll();
        }
          
    }
}
import { bootstrapApplication } from '@angular/platform-browser';
import { AppComponent } from './app.component';
import 'zone.js';
bootstrapApplication(AppComponent).catch((err) => console.error(err));

url property of the menu item is used to set the url of any website which will be opened upon clicking on them.

The following example shows the context menu with url for three websites.

app.component.ts
main.ts
import {Component, ViewEncapsulation, OnInit, ViewChild} from '@angular/core'
import { DiagramModule, DiagramContextMenuService,DiagramComponent } from '@syncfusion/ej2-angular-diagrams'
import { ContextMenuSettingsModel } from '@syncfusion/ej2-diagrams';

@Component({
imports: [
         DiagramModule
    ],

providers: [DiagramContextMenuService],
standalone: true,
    selector: "app-container",
    template: `<ejs-diagram #diagram id="diagram" width="100%" height="580px"  [contextMenuSettings]="contextMenuSettings">
        <e-nodes>
            <e-node id='node1' [offsetX]=100 [offsetY]=100 [width]=100 [height]=100>
                <e-node-annotations>
                    <e-node-annotation id="label1" content="Rectangle1">
                    </e-node-annotation>
                </e-node-annotations>
            </e-node>
            <e-node id='node2' [offsetX]=300 [offsetY]=100 [width]=100 [height]=100>
                <e-node-annotations>
                    <e-node-annotation id="label1" content="Rectangle2" >
                    </e-node-annotation>
                </e-node-annotations>
            </e-node>
        </e-nodes>
    </ejs-diagram>`,
    encapsulation: ViewEncapsulation.None
})
export class AppComponent {
    @ViewChild("diagram")
    public diagram?: DiagramComponent;
    public contextMenuSettings?: ContextMenuSettingsModel;

    ngOnInit(): void {
        //Enables the context menu
        this.contextMenuSettings = {
          //Enables the context menu
          show: true,
          items: [
            {
              text: 'Google.com',
              id: 'google',
              target: '.e-diagramcontent',
              url: 'https://www.google.co.in/',
            },
            {
              text: 'w3schools.com',
              id: 'W3Schools',
              target: '.e-diagramcontent',
              url: 'https://www.w3schools.com/',
            },
            {
              text: 'stackoverflow.com',
              id: 'stackoverflow',
              target: '.e-diagramcontent',
              url: 'https://stackoverflow.com/',
            }],
          // Hides the default context menu items
          showCustomMenuOnly: true,
        }
    }
}
import { bootstrapApplication } from '@angular/platform-browser';
import { AppComponent } from './app.component';
import 'zone.js';
bootstrapApplication(AppComponent).catch((err) => console.error(err));

Diagram provides template support for the context menu. The template for the context menu items can be customized before rendering by using the contextMenuBeforeItemRender event, which triggers while rendering each menu item.

In the following example, menu items are rendered with shortcut key codes for specific actions in the context menu using a template. The key codes for cut, copy, and paste actions are displayed at the right corner of the menu items by adding a span element in the contextMenuBeforeItemRender event.

app.component.ts
main.ts
import { Component, ViewEncapsulation, OnInit, ViewChild } from '@angular/core';
import { createElement } from "@syncfusion/ej2-base";
import { DiagramModule, DiagramContextMenuService ,DiagramComponent } from '@syncfusion/ej2-angular-diagrams';
import { ContextMenuSettingsModel } from '@syncfusion/ej2-diagrams';
import { MenuEventArgs } from '@syncfusion/ej2-navigations';

@Component({
imports: [
         DiagramModule
    ],

providers: [DiagramContextMenuService],
standalone: true,
    selector: "app-container",
    template: `<ejs-diagram #diagram id="diagram" width="100%" height="580px" [contextMenuSettings]="contextMenuSettings" (contextMenuBeforeItemRender)='contextMenuBeforeItemRender($event)'>
        <e-nodes>
            <e-node id='node1' [offsetX]=100 [offsetY]=100 [width]=100 [height]=100>
                <e-node-annotations>
                    <e-node-annotation id="label1" content="Rectangle1">
                    </e-node-annotation>
                </e-node-annotations>
            </e-node>
            <e-node id='node2' [offsetX]=300 [offsetY]=100 [width]=100 [height]=100 >
                <e-node-annotations>
                    <e-node-annotation id="label1" content="Rectangle2">
                    </e-node-annotation>
                </e-node-annotations>
            </e-node>
        </e-nodes>
    </ejs-diagram>`,
    encapsulation: ViewEncapsulation.None
})
export class AppComponent {
    @ViewChild("diagram")
    public diagram?: DiagramComponent;
    public contextMenuSettings?: ContextMenuSettingsModel;

    ngOnInit(): void {
        //Enables the context menu
        this.contextMenuSettings = {
          //Enables the context menu
          show: true,
          items: [{
            text: 'Cut  ', id: 'cut', target: '.e-diagramcontent',
            iconCss: 'e-cut e-icons'
          },
          {
            text: 'Copy  ', id: 'copy', target: '.e-diagramcontent',
            iconCss: 'e-icons e-copy'
          },
          {
            text: 'Paste', id:'paste', target: '.e-diagramcontent',
            iconCss: 'e-icons e-paste'
          }],
          //hides the default context menu items
          showCustomMenuOnly: true,
        }
    }
    public contextMenuBeforeItemRender(args: MenuEventArgs) {
        // To render template in li.
        let shortCutSpan: HTMLElement = createElement('span');
        let text: string = args.item.text as string;
        let shortCutText: string = text === 'Cut  ' ? 'Ctrl + X' : (text === 'Copy  ' ?
        'Ctrl + C' : 'Ctrl + V');
        shortCutSpan.textContent = shortCutText;
        args.element.appendChild(shortCutSpan);
        shortCutSpan.setAttribute('class', 'shortcut');
         
    }
}
import { bootstrapApplication } from '@angular/platform-browser';
import { AppComponent } from './app.component';
import 'zone.js';
bootstrapApplication(AppComponent).catch((err) => console.error(err));

Event	Description
`contextMenuBeforeItemRender`	Triggers while initializing each menu item.
`contextMenuOpen`	Triggers upon right-click before opening the context menu.
`contextMenuClick`	Triggers when a menu item is clicked.

The following example shows how to get these events.

app.component.ts
main.ts
import { Component, ViewEncapsulation, OnInit, ViewChild } from '@angular/core';
import { DiagramModule, DiagramContextMenuService,DiagramComponent } from '@syncfusion/ej2-angular-diagrams';
import { ContextMenuSettingsModel,DiagramBeforeMenuOpenEventArgs, } from '@syncfusion/ej2-diagrams';
import { MenuEventArgs } from '@syncfusion/ej2-navigations';

@Component({
imports: [
         DiagramModule
    ],

providers: [DiagramContextMenuService],
standalone: true,
    selector: "app-container",
    template: `<ejs-diagram #diagram id="diagram" width="100%" height="580px"  [contextMenuSettings]="contextMenuSettings" (contextMenuBeforeItemRender)="contextMenuBeforeItemRender($event)" (contextMenuOpen)="contextMenuOpen($event)" (contextMenuClick)="contextMenuClick($event)">
        <e-nodes>
            <e-node id='node1' [offsetX]=100 [offsetY]=100>
                <e-node-annotations>
                    <e-node-annotation id="label1" content="Rectangle1" [width]=100 [height]=100>
                    </e-node-annotation>
                </e-node-annotations>
            </e-node>
            <e-node id='node2' [offsetX]=300 [offsetY]=100 [width]=100 [height]=100>
                <e-node-annotations>
                    <e-node-annotation id="label1" content="Rectangle2" >
                    </e-node-annotation>
                </e-node-annotations>
            </e-node>
        </e-nodes>
        <e-connectors>
            <e-connector id='connector' type='Orthogonal' sourceID='node1' targetID='node2'>
            </e-connector>
        </e-connectors>
    </ejs-diagram>`,
    encapsulation: ViewEncapsulation.None
})
export class AppComponent {
    @ViewChild("diagram")
    public diagram?: DiagramComponent;
    public contextMenuSettings?: ContextMenuSettingsModel;
    ngOnInit(): void {
        //Enables the context menu
        this.contextMenuSettings = {
            //Enables the context menu
            show: true,
            items: [
                {
                    text: 'menu item 1',
                    id: 'item1',
                },
                {
                    text: 'menu item 2',
                    id: 'item2'
                },
            ],
            // Hides the default context menu items
            showCustomMenuOnly: true,
        } as ContextMenuSettingsModel;
    }

    public contextMenuBeforeItemRender(args: MenuEventArgs): void {
        //Triggers for each menu item
        console.log('context menu before item render');
    }
    public contextMenuOpen(args: DiagramBeforeMenuOpenEventArgs): void {
        //Triggers when the menu is openned
        console.log('context menu openned');
    }
      
    public contextMenuClick(args: MenuEventArgs): void {
        //Triggers when the item is clicked
        console.log('context menu clicked');
    }
    
}
import { bootstrapApplication } from '@angular/platform-browser';
import { AppComponent } from './app.component';
import 'zone.js';
bootstrapApplication(AppComponent).catch((err) => console.error(err));

Context menu in Angular Diagram component

Default context menu

Customize context menu

To Display custom menu alone

Context menu click

Context menu open

Context menu with Url

Template Support for Context menu

Context menu events

See Also