Angular 4 Reset按钮重置DropDown默认值

Question

我有一个看起来像这样的表单:

<form class="row" name="powerPlantSearchForm" (ngSubmit)="f.valid && searchPowerPlants()" #f="ngForm" novalidate>
          <div class="form-group col-xs-3" >
            <label for="powerPlantName">PowerPlant Name</label>
            <input type="text" class="form-control-small" [ngClass]="{ 'has-error': f.submitted && !powerPlantName.valid }" name="powerPlantName" [(ngModel)]="model.powerPlantName" #powerPlantName="ngModel" />
          </div>
          <div class="form-group col-xs-3" >
            <label for="powerPlantType">PowerPlant Type</label>
            <select class="form-control" [(ngModel)]="model.powerPlantType" name="powerPlantType">
              <option value="" disabled>--Select Type--</option>
              <option [ngValue]="powerPlantType" *ngFor="let powerPlantType of powerPlantTypes">
                {{ powerPlantType }}
              </option>
            </select>
          </div>
          <div class="form-group col-xs-3" >
            <label for="organizationName">Organization Name</label>
            <input type="text" class="form-control-small" name="powerPlantOrganization" [(ngModel)]="model.powerPlantOrg" #organizationName="ngModel" />
          </div>
          <div class="form-group col-xs-3" >
            <label for="powerPlantStatus">PowerPlant Active Status</label>
            <select class="form-control" [(ngModel)]="model.powerPlantStatus" name="powerPlantStatus">
              <option value="" disabled>--Select Status--</option>
              <option [ngValue]="powerPlantStatus" *ngFor="let powerPlantStatus of powerPlantStatuses">
                {{ powerPlantStatus }}
              </option>
            </select>
          </div>
          <div class="form-group col-md-3 col-xs-4">
            <button [disabled]="loading" class="btn btn-primary">Search</button>
            <img *ngIf="loading" src="data:image/gif;base64,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" />
          </div>
          <div class="form-group col-md-3 col-xs-3">
            <button class="btn btn-primary" (click)="f.reset()">Reset</button>
          </div>
        </form>

布局如下所示:

单击"重置"按钮时,下拉列表的默认值将消失 - 如下图所示.

即使在按下重置按钮后,如何确保保留默认值？

有任何想法吗？

Answer 1

在元素列表中有一个额外的值 id = -1

types:any[]=[
                {id:-1,Name:'Select One'},
                {id:1,Name:'abc'},
                {id:2,Name:'abdfsdgsc'}
    ];

HTML看起来像

<select [(ngModel)]="selectedElement.id">
     <option *ngFor="let type of types" [ngValue]="type.id"> {{type.Name}}</option>
</select>

重置时

reset(){
   this.selectedElement = {id:-1,Name:'Select One'};
  }

现场演示

Answer 2

您可以将f.reset()更改为reset().你把它放在哪里

reset(){
    this.model.powerPlantType = '';
    this.model.powerPlantStatus = '';
    // and other input resettings too
  }

然后改变

<button type="button" (click)="reset()">Reset</button>

DEMO