How to clear ng-select selection

问题:

Is it possible to programmatically clear the selection of an ng-select dropdown? I'm wanting the equivalent behaviour of clicking the clear icon, but triggered programmatically.

I was expecting a clear() method or something similar, but the documented API doesn't have anything along those lines.

This is my dropdown code:

<ng-select class="ng-select-wrap"
           [searchFn]="multiTermSearch"
           [items]="calculationOptions"
           placeholder="Please select..."
           name="calculation"
           #calculationValue="ngModel"
           [(ngModel)]="selectedCalculation">
</ng-select>

回答1:

Here is solution from comment:

  // Access ng-select
  @ViewChild(NgSelectComponent) ngSelectComponent: NgSelectComponent;

  // Call to clear
  this.ngSelectComponent.handleClearClick();

Note that handleClearClick isn't exposed in docs as public api method however as Tim mentioned it's public method so it's possible to call it.

回答2:

I was looking for the same but for templates to invoke it outside ng-select. So, the below worked fine for me following the accepted answer. ^_^

<ng-select class="ng-select-wrap"
           [searchFn]="multiTermSearch"
           [items]="calculationOptions"
           placeholder="Please select..."
           name="calculation"
           (clear)="resetCalculations();"
           [(ngModel)]="selectedCalculation" #selectDropdown>
</ng-select>

<input type="button" (click)="selectDropdown.handleClearClick()">

This also makes sure the resetCalculations() being called.

回答3:

Clearing the selection can be achieved by simply setting the ngModel value to null. In the case of the above example:

this.selectedCalculation = null;

This isn't exactly the same as clicking the clear icon, as it doesn't trigger the (clear) output event, but it was sufficient for my needs.

回答4:

Like @tim answer is correct but I will prefer you set as an empty array instead of null just to save any loop break.

this.selectedCalculation = [];

回答5:

Agree with @tim and @AlexOnozor, I have successfully used 'selectedCalculation' as 'string', 'string[]', 'object[]' with Reactive Forms ( and as 'string' with ngModel ) and your suggested method worked smoothly. I also tried using 'handleClearClick' but failed. Will update if i find my way through it.

So, this.selectedCalculation = '' or this.selectedCalculation= [] (for multipleSelect = true) should work.

回答6:

Assuming the originally posted code sample below.

<ng-select class="ng-select-wrap"
           [searchFn]="multiTermSearch"
           [items]="calculationOptions"
           placeholder="Please select..."
           name="calculation"
           #calculationValue="ngModel"
           [(ngModel)]="selectedCalculation">
</ng-select>

The selectedCalculation variable is created as an array and not a string, as the ng-select can allow for multiple values to be selected if [multiple]="true" is set.

To clear the selected value(s) in the array programmatically, use:

this.selectedCalculation = [];

Should you need to clear the bound items, use:

this.calculationOptions = [];

Both of the above can be done by adding the (change) handler in HTML.

(change)="change($event)

Something like this in your TypeScript.

change(event: any): void {
   this.calculationOptions = [];
   this.selectedCalculation = [];
  }

回答7:

Even thought @Buczkowski answer clears ng-select, it also does a focus on input, which isn't needed for all cases. So i used other method: clearModel

  // Access ng-select
  @ViewChild(NgSelectComponent) ngSelectComponent: NgSelectComponent;

  // Call to clear
  this.ngSelectComponent.clearModel();

So if you need to just clear input, use clearModel method. Else if focus and clear is needed, use handleClearClick.