how to take the value of Dropdown in ng-bootstrap?

Answer 1

This runs without any javascript backend code. Solution is build upon angular template variables. Until no item is selected a place holder text "Select Environment" is displayed.

<div ngbDropdown class="d-inline-block">
    <button class="btn btn-outline-primary" id="dropdown"
       ngbDropdownToggle>{{ selectedValue.value || "Select Environment" }}</button>
    <div ngbDropdownMenu aria-labelledby="dropdown" #selectedValue>
      <div *ngFor="let env of environments;" >
        <button ngbDropdownItem id="option" on-click="selectedValue.value=env">{{env}} 
        </button>
      </div>
    </div>
</div>

Answer 2

You need to add a click event:

 <button class="dropdown-item" (click)="changeAction(obj)">

In the component:

changeAction(obj) {
        //your logic here
}