angular - 如何将表单控件添加到 angular 8 中的文本区域

Question

我正在处理联系表单，但无法让表单使用 ngModel 提交 textarea 值。我不断收到来自浏览器的错误，我将在下面发布

我试过使用reactiveforms，但最终还是遇到了和以前一样的问题和错误。

//HTML

<form #myform="ngForm" (ngSubmit)="send(myform)" autocomplete="off">
  <ol>
    <li>
      <label>What's your name?</label>
      <input ngModel name="q1" type="text" required/>
    </li>
    <li>
      <label>What's your email address?</label>
      <input ngModel name="q2" type="email" required/>
    </li>
    <li>
      <label>What's the purpose of the message?</label>
      <div>
        <span><input ngModel id="q3a" name="q3" type="radio" value="choice1" /><label for="q3a">choice 1</label></span>
        <span><input ngModel id="q3b" name="q3" type="radio" value="choice2" /><label for="q3b">choice 2</label></span>
        <span><input ngModel id="q3c" name="q3" type="radio" value="choice3" /><label for="q3c">choice 3</label></span>
      </div>
    </li>
    <li>
      <label>This is where your message goes!</label>
      <textArea [(ngModel)]="q4" name="q4" rows="5" cols="60" required>
      </textArea>
    </li>
  </ol>
  <input type="submit"/>
  <button type="submit">Send Message</button>
</form>

// typescript

send(form: NgForm){
  console.log(form.value);
}

//控制台输出

{q1: "name", q2: "email", q3: "choice1", q4: undefined}

//错误

Error: Uncaught (in promise): Error: No value accessor for form control with name: 'q4'
Error: No value accessor for form control with name: 'q4'
    at _throwError (forms.js:3313)
    at setUpControl (forms.js:3139)
    at forms.js:5963
    at ZoneDelegate.invoke (zone-evergreen.js:359)
    at Object.onInvoke (core.js:39698)
    at ZoneDelegate.invoke (zone-evergreen.js:358)
    at Zone.run (zone-evergreen.js:124)
    at zone-evergreen.js:855
    at ZoneDelegate.invokeTask (zone-evergreen.js:391)
    at Object.onInvokeTask (core.js:39679)
    at resolvePromise (zone-evergreen.js:797)
    at zone-evergreen.js:862
    at ZoneDelegate.invokeTask (zone-evergreen.js:391)
    at Object.onInvokeTask (core.js:39679)
    at ZoneDelegate.invokeTask (zone-evergreen.js:390)
    at Zone.runTask (zone-evergreen.js:168)
    at drainMicroTaskQueue (zone-evergreen.js:559)"

Answer 1

有了这个符号

<textArea [(ngModel)]="q4" name="q4" rows="5" cols="60" required>

你让 Angular 感到困惑。它同时拥有名称和应处理的 ngModel，因此它举起双手说“废话”，我的意思是“未定义”。看看你之前是怎么用输入做的？尝试

<textArea [(ngModel)]="q4" rows="5" cols="60" required>

或者

<textArea ngModel name="q4" rows="5" cols="60" required>