@kreash/ngx-contextmenu

v18.1.0

Published

4 months ago

An Angular component to show a context menu on an arbitrary component

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kreash

contextmenu ngx-contextmenu angular angular-contextmenu angular2 angular2-contextmenu ngx ng2 ng2-contextmenu

ngx-contextmenu

A context menu built with Angular (v18). Bootstrap classes are included in the markup, but there is no explicit dependency on Bootstrap.

Supported Angular versions: 18, 17

Installation

npm i @kreash/ngx-contextmenu @angular/cdk
import ContextMenuModule into your app module
Make sure to include <!doctype html> at the top of your index.html

Usage

Template

<ul>
  <li *ngFor="let item of items" [contextMenu]="basicMenu" [contextMenuSubject]="item">Right Click: {{item?.name}}</li>
</ul>
<context-menu>
  <ng-template contextMenuItem (execute)="showMessage('Hi, ' + $event.item.name)"> Say hi! </ng-template>
  <ng-template contextMenuItem divider="true"></ng-template>
  <ng-template contextMenuItem let-item (execute)="showMessage($event.item.name + ' said: ' + $event.item.otherProperty)"> Bye, {{item?.name}} </ng-template>
  <ng-template contextMenuItem passive="true"> Input something: <input type="text" /> </ng-template>
</context-menu>

Component Code

@Component({
  ...
})
export class MyContextMenuClass {
  public items = [
      { name: 'John', otherProperty: 'Foo' },
      { name: 'Joe', otherProperty: 'Bar' }
  ];
  @ViewChild(ContextMenuComponent) public basicMenu: ContextMenuComponent;
}

Context Menu Items

Each context menu item is a <ng-template> element with the contextMenuItem attribute directive applied.
If the item object is used in the context menu item template, the let-item attribute must be applied to the <ng-template> element. ** Note: ** Make sure to use the item?.property syntax in the template rather than item.property as the item will be initially undefined.
Every context menu item emits execute events. The $event object is of the form { event: MouseEvent, item: any } where event is the mouse click event that triggered the execution and item is the current item.
The divider input parameter is optional. Items default to normal menu items. If divider is true, all the other inputs are ignored.
The passive input parameter is optional. If passive is true, the menu item will not emit execute events or close the context menu when clicked.
The enabled input parameter is optional. Items are enabled by default. This can be a boolean value or a function definition that takes an item and returns a boolean.
The visible input parameter is optional. Items are visible by default. This property enables you to show certain context menu items based on what the data item is. This can be a boolean value or a function definition that takes an item and returns a boolean.
Within the template, you have access to any components and variables available in the outer context.

<context-menu>
  <ng-template contextMenuItem let-item [visible]="isMenuItemType1" [enabled]="false" (execute)="showMessage('Hi, ' + $event.item.name)">
    Say hi, {{item?.name}}! <my-component [attribute]="item"></my-component>
    With access to the outside context: {{ outsideValue }}
  </ng-template>
</context-menu>

public outsideValue = "something";
public isMenuItemType1(item: any): boolean {
  return item.type === 'type1';
}

Sub-menus

You can specify sub-menus like this:

<ul>
  <li *ngFor="let item of items" [contextMenu]="basicMenu" [contextMenuSubject]="item">Right Click: {{item?.name}}</li>
</ul>
<context-menu>
  <ng-template contextMenuItem [subMenu]="saySubMenu"> Say... </ng-template>
  <context-menu #saySubMenu>
    <ng-template contextMenuItem (execute)="showMessage('Hi, ' + $event.item.name)"> ...hi! </ng-template>
    <ng-template contextMenuItem (execute)="showMessage('Hola, ' + $event.item.name)"> ...hola! </ng-template>
    <ng-template contextMenuItem (execute)="showMessage('Salut, ' + $event.item.name)"> ...salut! </ng-template>
  </context-menu>
  <ng-template contextMenuItem divider="true"></ng-template>
  <ng-template contextMenuItem let-item (execute)="showMessage($event.item.name + ' said: ' + $event.item.otherProperty)"> Bye, {{item?.name}} </ng-template>
  <ng-template contextMenuItem passive="true"> Input something: <input type="text" /> </ng-template>
</context-menu>

Notes:

The sub <context-menu> can not be placed inside the <ng-template> that references it.
Sub-menus may be nested as deeply as you wish.

Note: The imperative way of declaring context menu items has been removed. i.e. You can't pass an actions property to contextMenuService.show.next().

Using `visible` and `enabled` functions

If you need access to properties in your component from within the enabled or visible functions, you can pass in an arrow function.

<ng-template ... [visible]="isMenuItemOutsideValue"></ng-template>

public outsideValue = "something";
public isMenuItemOutsideValue = (item: any): boolean => {
  return item.type === this.outsideValue;
}

Multiple Context Menus

You can use multiple context menus in the same component if you would like.

<ul>
  <li *ngFor="let item of items" [contextMenu]="basicMenu" [contextMenuSubject]="item">{{item?.name}}</li>
</ul>
<context-menu #basicMenu> ... </context-menu>

<ul>
  <li *ngFor="let item of items" [contextMenu]="otherMenu" [contextMenuSubject]="item">{{item?.name}}</li>
</ul>
<context-menu #otherMenu> ... </context-menu>

@ViewChild('basicMenu') public basicMenu: ContextMenuComponent;
@ViewChild('otherMenu') public otherMenu: ContextMenuComponent;

Context Menu In a Different Component

If your <context-menu> component is in a different component from your list, you'll need to wire up the context menu event yourself.

<ul>
  <li *ngFor="let item of items" (contextmenu)="onContextMenu($event, item)">Right Click: {{item.name}}</li>
</ul>

import { ContextMenuService } from 'ngx-contextmenu';

@Component({
  ...
})
export class MyContextMenuClass {
  public items = [
      { name: 'John', otherProperty: 'Foo' },
      { name: 'Joe', otherProperty: 'Bar' }
  ];

  // Optional
  @Input() contextMenu: ContextMenuComponent;

  constructor(private contextMenuService: ContextMenuService) {}

  public onContextMenu($event: MouseEvent, item: any): void {
    this.contextMenuService.show.next({
      // Optional - if unspecified, all context menu components will open
      contextMenu: this.contextMenu,
      event: $event,
      item: item,
    });
    $event.preventDefault();
    $event.stopPropagation();
  }
}

Triggering the Context Menu with a Different Event

The context menu can be triggered at any point using the method above. For instance, to trigger the context menu with a left click instead of a right click, use this html:

<ul>
  <li *ngFor="let item of items" (click)="onContextMenu($event, item)">Left Click: {{item.name}}</li>
</ul>

This could be (keydown), (mouseover), or (myCustomEvent) as well.

Positioning the Context Menu around an element

If you want to override the context menu positioning to be appended to an element instead of based on mouse position, provide an anchorElement to the contextMenuService. This makes sense if you want to trigger the context menu with a non-MouseEvent.

public onContextMenu($event: KeyboardEvent, item: any): void {
  this.contextMenuService.show.next({
    anchorElement: $event.target,
    // Optional - if unspecified, all context menu components will open
    contextMenu: this.contextMenu,
    event: <any>$event,
    item: item,
  });
  $event.preventDefault();
  $event.stopPropagation();
}

Custom Styles

The html that is generated for the context menu looks like this:

<div class="dropdown ngx-contextmenu">
  <ul class="dropdown-menu">
    <li>
      <a><!-- the template for each context menu item goes here --></a>
      <span><!-- the template for each passive context menu item goes here --></span>
    </li>
  </ul>
</div>

You can key off of the ngx-contextmenu class to create your own styles. Note that the ul.dropdown-menu will have inline styles applied for position, display, left and top so that it will be positioned at the cursor when you right-click.

.ngx-contextmenu .dropdown-menu {
  border: solid 1px chartreuse;
  background-color: darkgreen;
  padding: 0;
}
.ngx-contextmenu li {
  display: block;
  border-top: solid 1px chartreuse;
  text-transform: uppercase;
  text-align: center;
}
.ngx-contextmenu li:first-child {
  border-top: none;
}
.ngx-contextmenu a {
  color: chartreuse;
  display: block;
  padding: 0.5em 1em;
}
.ngx-contextmenu a:hover {
  color: darkgreen;
  background-color: chartreuse;
}

Bootstrap 4

If you're using Bootstrap 4, you can specify a useBootstrap4 property in the forRoot function of the ContextMenuModule in order to get the appropriate class names. Like this:

@NgModule({
  import: [
    ContextMenuModule.forRoot({
      useBootstrap4: true,
    }),
  ],
})
export class AppModule {}

Or, if you want to repeat yourself, you can add a useBootstrap4 attribute to each context-menu component. Like this:

<context-menu [useBootstrap4]="true"></context-menu>

Different styling on menus

If you want to style one menu differently than other menus, you can add a custom style to the menu.

<context-menu [menuClass]="'mystyle'"></context-menu>

Please note that the style needs to be global to affect the menu, since the menu element is added to the page outside the component that triggers the menu.

AutoFocus

You can optionally set focus on the context menu whenever it opens. This enables a user to easily tab through the context menu items and press enter to select them.

@NgModule({
  import: [
    ContextMenuModule.forRoot({
      autoFocus: true,
    }),
  ],
})
export class AppModule {}

Keyboard navigation

You can use the keyboard to manipulate the context menu. Note: Keyboard navigation should be used in conjunction with autoFocus, since key events are only captured when the context menu is focused.

| Key | Action | | :------------: | ---------------------------------------------- | | ArrowDown | Move to next menu item (wrapping) | | ArrowUp | Move to previous menu item (wrapping) | | ArrowRight | Open submenu of current menu item if present | | ArrowLeft | Close current menu unless already at root menu | | Enter | Space | Open submenu or execute current menu item | | Esc | Close current menu |

Disable Context Menu

If you need to disable the context menu, you can pass a boolean to the [disabled] input:

<context-menu [disabled]="true"></context-menu>

Close event emitter

There is a (close) output EventEmitter that you can subscribe to for notifications when the context menu closes (either by clicking outside or choosing a menu item).

<context-menu (close)="processContextMenuCloseEvent()"></context-menu>

Dynamic context menu

The items in the context menu are completely controlled by the contextMenuActions object.

<ul>
  <li *ngFor="item in items" [contextMenu]="myContextMenu" [contextMenuSubject]="item">Right Click: {{item.name}}</li>
</ul>
<context-menu #myContextMenu>
  <ng-template *ngFor="let action of contextMenuActions" contextMenuItem let-item [visible]="action.visible" [enabled]="action.enabled" [divider]="action.divider" (execute)="action.click($event.item)"> {{ action.html($event.item) }} </ng-template>
</context-menu>

@Component({
  ...
})
export class MyContextMenuClass {
  public items = [
      { name: 'John', otherProperty: 'Foo', type: 'type1' },
      { name: 'Joe', otherProperty: 'Bar', type: 'type2' }
  ];
  @ViewChild(ContextMenuComponent) public contextMenu: ContextMenuComponent;
  public contextMenuActions = [
        {
          html: (item) => `Say hi!`,
          click: (item) => alert('Hi, ' + item.name),
          enabled: (item) => true,
          visible: (item) => item.type === 'type1',
        },
        {
          divider: true,
          visible: true,
        },
        {
          html: (item) => `Something else`,
          click: (item) => alert('Or not...'),
          enabled: (item) => false,
          visible: (item) => item.type === 'type1',
        },
      ];
}