角度2中没有默认值的FormControl布尔值

Question

I'm using reactive forms in angular 2 (4.1.2)

I have a boolean property which I don't want to have a default value but it should be required.

This is how I create my form:

constructor(private fb: FormBuilder) {
    this.form = this.fb.group({
        payedOvertime: [false, Validators.required],
    });
}

And my html:

<div class="form-group">
    <label>Payed overtime</label>
    <label>
        <input type="radio" name="payedOvertime" formControlName="payedOvertime" [value]="true" />Yes
    </label>
    <label>
        <input type="radio" name="payedOvertime" formControlName="payedOvertime" [value]="false" />No
    </label>
</div>

The problem is that while this works the radiobutton is preselected but I do not want that, rather it should have to be selected by clicking at one of the radio-buttons. If neither of the radiobuttons are clicked I want the form to be invalid.

Answer 1

Change payedOvertime: [false, Validators.required] to payedOvertime: [null, Validators.required] .

Given that you set it to false , it matches the value of No radio button in the template and it selects it by default (rightly so). Setting it to null will prevent Angular from matching the value with any of those declared in the template and thus non of those radio buttons will be selected.

Answer 2

仅将Validators.required更改为Validators.requiredTrue ，例如：

payedOvertime: [false, Validators.requiredTrue]