ngx-bootstrap dropdown component is toggleable and provides contextual overlay to display list of links etc. With dropdown directives we can make dropdowns interactive.

BsDropdownDirective

selector

• [bsDropdown],[dropdown]

Inputs

• autoClose − boolean, Indicates that dropdown will be closed on item or document click, and after pressing ESC

• container − string, A selector specifying the element the popover should be appended to.

• dropup − boolean, This attribute indicates that the dropdown should be opened upwards.

• insideClick − boolean, This attribute indicates that the dropdown shouldn”t close on inside click when autoClose is set to true.

• isAnimated − boolean, Indicates that dropdown will be animated

• isDisabled − boolean, Disables dropdown toggle and hides dropdown menu if opened

• isOpen − boolean, Returns whether or not the popover is currently being shown

• placement − string, Placement of a popover. Accepts: “top”, “bottom”, “left”, “right”

• triggers − string, Specifies events that should trigger. Supports a space separated list of event names.

Outputs

• isOpenChange − Emits an event when isOpen change

• onHidden − Emits an event when the popover is hidden

• onShown − Emits an event when the popover is shown

Methods

• show() − Opens an element”s popover. This is considered a ”manual” triggering of the popover.

• hide() − Closes an element”s popover. This is considered a ”manual” triggering of the popover.

• toggle() − Toggles an element”s popover. This is considered a ”manual” triggering of the popover.

• setConfig() − Set config for popover

Example

As we”re going to use dropdowns, We”ve to update app.module.ts used in ngx-bootstrap DatePicker chapter to use BsDropdownModule and BsDropdownConfig.

Update app.module.ts to use the BsDropdownModule and BsDropdownConfig.

app.module.ts

import { BrowserModule } from ''@angular/platform-browser'';
import { NgModule } from ''@angular/core'';
import { BrowserAnimationsModule } from ''@angular/platform-browser/animations'';
import { AppComponent } from ''./app.component'';
import { TestComponent } from ''./test/test.component'';
import { AccordionModule } from ''ngx-bootstrap/accordion'';
import { AlertModule,AlertConfig } from ''ngx-bootstrap/alert'';
import { ButtonsModule } from ''ngx-bootstrap/buttons'';
import { FormsModule } from ''@angular/forms'';
import { CarouselModule } from ''ngx-bootstrap/carousel'';
import { CollapseModule } from ''ngx-bootstrap/collapse'';
import { BsDatepickerModule, BsDatepickerConfig } from ''ngx-bootstrap/datepicker'';
import { BsDropdownModule,BsDropdownConfig } from ''ngx-bootstrap/dropdown'';

@NgModule({
   declarations: [
      AppComponent,
      TestComponent
   ],
   imports: [
      BrowserAnimationsModule,
      BrowserModule,
      AccordionModule,
      AlertModule,
      ButtonsModule,
      FormsModule,
      CarouselModule,
      CollapseModule,
      BsDatepickerModule.forRoot(),
      BsDropdownModule
   ],
   providers: [AlertConfig, BsDatepickerConfig, BsDropdownConfig],
   bootstrap: [AppComponent]
})
export class AppModule { }

Update test.component.html to use the dropdowns.

test.component.html

<div class="btn-group" dropdown #dropdown="bs-dropdown" [autoClose]="false">
   <button id="button-basic" dropdownToggle type="button" 
      class="btn btn-primary dropdown-toggle"
      aria-controls="dropdown-basic">
      Menu <span class="caret"></span>
   </button>
   <ul id="dropdown-basic" *dropdownMenu class="dropdown-menu"
      role="menu" aria-labelledby="button-basic">
      <li role="menuitem"><a class="dropdown-item" href="#">File</a></li>
      <li role="menuitem"><a class="dropdown-item" href="#">Edit</a></li>
      <li role="menuitem"><a class="dropdown-item" href="#">Search</a></li>
      <li class="divider dropdown-divider"></li>
      <li role="menuitem"><a class="dropdown-item" href="#">Recents</a>
      </li>
   </ul>
</div>
<button type="button" class="btn btn-primary" 
   (click)="dropdown.isOpen = !dropdown.isOpen">Show/Hide
</button>

Update test.component.ts for corresponding variables and methods.

test.component.ts

import { Component, OnInit } from ''@angular/core'';

@Component({
   selector: ''app-test'',
   templateUrl: ''./test.component.html'',
   styleUrls: [''./test.component.css'']
})
export class TestComponent implements OnInit {
   constructor() {}

   ngOnInit(): void {}
}

Build and Serve

Run the following command to start the angular server.

ng serve

Once server is up and running. Open http://localhost:4200 and verify the following output.