在 Angular 6 中重置反应式表单时不会禁用输入 [英] Input does not disable on resetting a Reactive Form in Angular 6

问题描述

我针对我的问题创建了一个StackBlitz 示例.

I have created a StackBlitz example of my problem.

我有一个构建表单的FormService，由initForm()方法中的组件获取:-

I have a FormService that builds a form, which is obtained by the component in the initForm() method:-

public getForm() {
  return this.fb.group({
    cb1: this.fb.control(false),
    cb2: this.fb.control(false),
    inputBox: this.fb.control({value: '', disabled: true}, Validators.required)
  });
}

如果没有选中任何复选框，我需要禁用输入文本框.这让我做这样的事情:-

I need to disable the input text box if none of the checkboxes is selected. Which brings me to do something like this :-

if(!this.cb1.value && !this.cb2.value) {
  this.isCheckboxSelectionInvalid = true;
  this.inputBox.disable();
} else {
  this.isCheckboxSelectionInvalid = false;
  this.inputBox.enable();
}

这适用于所有默认场景 - 但是有一个问题.当我调用 resetForm()(前提是通过选中其中一个复选框启用输入)时，它基本上调用了与 initForm() 相同的方法，输入保持启用状态.即使在我调用验证复选框选择并禁用 initForm() 方法中的输入的方法之后也是如此.

This works for all default scenarios - however there is a problem. When I call resetForm() (provided the input is enabled by checking one of the checkboxes) which basically calls the same method of initForm(), the input stays enabled. This is even after I call the method that validates checkbox selection and disables the input in the initForm() method.

为了理智，我记录了输入的 disabled 属性的值 - 记录 true.

For sanity, I logged the value of the input's disabled property - which logs true.

为什么输入没有被禁用呢?任何帮助将不胜感激，这是工作中的问题.

Why is it that the input doesn't get disabled then? Any help would be very appreciated, this is a problem at work.

推荐答案

您遇到的问题与 angular bug 有关，您可以找到更多信息 此处.

The problem you are facing is related to an angular bug, you can find more info here.

有一些解决方法对我有用:

1. 在 setTimeout 中调用禁用函数.

validateCheckboxSelectionAndChangeInputState() {
  if (!this.cb1.value && !this.cb2.value) {
     this.isCheckboxSelectionInvalid = true;
     setTimeout(() => {
        this.inputBox.disable();
     }, 0);
  } else {
     this.isCheckboxSelectionInvalid = false;
     this.inputBox.enable();
  }
}

1. 直接设置禁用属性:

<input type="text" [attr.disabled]="form.controls['inputBox'].disabled" formControlName="inputBox" />

1. 在调用启用/禁用函数之前调用detectChanges.

validateCheckboxSelectionAndChangeInputState() {
  this.ref.detectChanges();
  if (!this.cb1.value && !this.cb2.value) {
    this.isCheckboxSelectionInvalid = true;
    this.inputBox.disable();
  } else {
      this.isCheckboxSelectionInvalid = false;
      this.inputBox.enable();
  }
}

---

与问题无关的建议:

有了启用或禁用控件的想法，可以订阅表单valueChanges:

With the idea of ​​enabling or disabling the control, you can subscribe to form valueChanges:

  initForm() {
    this.form = this.formService.getForm();
    this.cb1 = this.form.get("cb1");
    this.cb2 = this.form.get("cb2");
    this.inputBox = this.form.get("inputBox");
    this.form.valueChanges.subscribe(
      this.validateCheckboxSelectionAndChangeInputState.bind(this)
    );     
  }

  validateCheckboxSelectionAndChangeInputState(controls) {
    if (this.inputBox.disabled && controls.cb1 && controls.cb2) {
      this.inputBox.enable();
    } 
    if(this.inputBox.enabled && !controls.cb1 && !controls.cb) {
       setTimeout(() => {
          this.inputBox.disable();
       }, 0);
    } 
  }

  toggleCb1() {
    this.cb1.setValue(!this.cb1.value);
  }

  toggleCb2() {
    this.cb2.setValue(!this.cb2.value);
  }

  resetForm() {
    this.initForm();
  }

你也可以[禁用]使用form.valid和Validators.requiredTrue的按钮:

Also you can [disabled] the button using form.valid, and using the Validators.requiredTrue:

html

 <button [disabled]="!form.valid" (click)="submitForm()">
    Submit
  </button>

ts

public getForm() {
    return this.fb.group({
      cb1: this.fb.control(false, [Validators.requiredTrue]),
      cb2: this.fb.control(false, [Validators.requiredTrue]),
      inputBox: this.fb.control(
        { value: "", disabled: true },
        [Validators.required]
      )
    });
  }

参见 https://stackblitz.com/edit/angular-6-reactive-form-disable-jn4cf8?file=src%2Fapp%2Fapp.component.ts

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