Question

我在表单中有多个下拉菜单，但是我无法将“请选择”作为这些下拉菜单的默认选择。

我的下拉菜单完全空白。单击后，我们可以看到项目已绑定在其中。

HTML

<form novalidate (ngSubmit)="onSubmit(projectinformationFrm)" [formGroup]="projectinformationFrm">
    <select [(ngModel)]="selectedOrganization" placeholder="Organization" formControlName="OrganizationId" (change)="onSelectOrgEdit($event.target.value)" class="form-control">

        <option *ngFor="let org of OrganizationList" [ngValue]="org .OrganizationId" [selected]="org.OrganizationId==selectedOrganization">
        {{ org .OrganizationName }}
        </option>
    </select>

    <div>
        <a class="btn btn-default" (click)="modal.dismiss()"><span class="glyphicon glyphicon-remove"></span>Cancel</a>
        <button type="submit" class="btn btn-primary"><span class="glyphicon glyphicon-save"></span>Save</button>
    </div>

</form>

Component.ts

public selectedOrganization: number=0;


LoadListforProjectManager(): void {
    try {

        this._service.get(URL)
            .subscribe(data => { this.OrganizationList = data; },
                error => this.msg = <any>error);
    }
    catch (e) {
        this._errorLogService.LogError(e);
    }
}

我还从存储过程中将0,"--Please Select--"作为列表的第一项。

Answer 1

而不是将列表中的第一项作为 Please Select 来获取，而是在组件模板中创建它。也不要将[(ngModel)]与ReactiveForms方法一起使用。像这样：

<form novalidate (ngSubmit)="onSubmit(projectinformationFrm)" [formGroup]="projectinformationFrm">
    <select placeholder="Organization" formControlName="OrganizationId" (change)="onSelectOrgEdit($event.target.value)" class="form-control">

    <option value="null" disabled>Please select</option>

    <option *ngFor="let org of OrganizationList" [ngValue]="org .OrganizationId" [selected]="org.OrganizationId==selectedOrganization">
      {{ org .OrganizationName }}
    </option>
  </select>

  <div>
    <a class="btn btn-default" (click)="modal.dismiss()"><span class="glyphicon glyphicon-remove"></span>Cancel</a>
    <button type="submit" class="btn btn-primary"><span class="glyphicon glyphicon-save"></span>Save</button>
  </div>

</form>

这是您推荐的Working Sample StackBlitz。

选择-请选择-默认为angular 4.0 html表单中的下拉菜单

1 个答案: