角材料:垫选择不选择默认 [英] Angular Material: mat-select not selecting default

问题描述

我有一个mat-select选项，其中选项是数组中定义的所有对象.我正在尝试将值默认设置为选项之一，但是在页面呈现时仍处于选中状态.

I have a mat-select where the options are all objects defined in an array. I am trying to set the value to default to one of the options, however it is being left selected when the page renders.

我的打字稿文件包含:

  public options2 = [
    {"id": 1, "name": "a"},
    {"id": 2, "name": "b"}
  ]
  public selected2 = this.options2[1].id;

我的HTML文件包含:

My HTML file contains:

  <div>
    <mat-select
        [(value)]="selected2">
      <mat-option
          *ngFor="let option of options2"
          value="{{ option.id }}">
        {{ option.name }}
      </mat-option>
    </mat-select>
  </div>

我尝试将selected2和value在mat-option中设置为对象及其ID，并且尝试在mat-select中同时使用[(value)]和[(ngModel)]，但是没有一个工作.

I have tried setting selected2 and the value in mat-option to both the object and it's id, and have tried using both [(value)] and [(ngModel)] in the mat-select, but none are working.

我正在使用材料版本2.0.0-beta.10

I am using material version 2.0.0-beta.10

推荐答案

为模板中的值使用绑定.

Use a binding for the value in your template.

value="{{ option.id }}"

应该是

[value]="option.id"

然后在您选择的值中使用ngModel而不是value.

And in your selected value use ngModel instead of value.

<mat-select [(value)]="selected2">

应该是

<mat-select [(ngModel)]="selected2">

完整代码:

<div>
  <mat-select [(ngModel)]="selected2">
    <mat-option *ngFor="let option of options2" [value]="option.id">{{ option.name }}</mat-option>
  </mat-select>
</div>

---

从版本2.0.0-beta.12起 a> 材料选择现在接受mat-form-field元素作为父元素，因此与其他物料输入控件一致.升级后，将div元素替换为mat-form-field元素.

---

On a side note as of version 2.0.0-beta.12 the material select now accepts a mat-form-field element as the parent element so it is consistent with the other material input controls. Replace the div element with mat-form-field element after you upgrade.

<mat-form-field>
  <mat-select [(ngModel)]="selected2">
    <mat-option *ngFor="let option of options2" [value]="option.id">{{ option.name }}</mat-option>
  </mat-select>
</mat-form-field>

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