I have such reactive form:
constructor(...){
this.form = this.formBuilder.group({
name: ['', Validators.compose([Validators.required, Validators.maxLength(50)])],
memes: this.formBuilder.array([
this.initMemes('TrollFace')
])
});
}
initMemes (name?) {
return this.formBuilder.group({
id: [''], name: [name]
});
}
later i can add some more memes
:
addMemes () {
const control = <FormArray>this.form.controls['memes'];
control.push(this.initMemes('anyName'));
}
and then if i get form values i get:
this.form.controls['memes'].value
- here i have array
But there is a case, when i need this this.form.controls['memes'].value
to set to an empty array, how is it possible to do?
If i set it this way:
this.form.controls['memes'].setValue([])
I got error: Must supply a value for form control at index: 0.
what i do wrong?
EDIT:
As of newer versions, Angular now supports clearing a FormArray
with clear()
:
(<FormArray>this.form.get('memes')).clear();
ORIGINAL:
Tried a few things: reset()
, setControl()
, but the following was the only solution I found to work that actually resets the whole array to []
, other options worked, but they left the formgroups in place, just emptied the values.
So how I got it to work, was to iterate the form array and delete each form group with that particular index in the loop:
const control = <FormArray>this.form.controls['memes'];
for(let i = control.length-1; i >= 0; i--) {
control.removeAt(i)
}
If there is a better way, I'm open for suggestions! :)
Try this.myForm.controls['myFormArray'] = this.formBuilder.array([]);
with formBuilder service instantiated in your constructor.
FORM
this.form = this._formB.group({
blocks: this._formB.array([])
});
1st method
let fArray = <FormArray>this.form.controls['blocks'];
while (fArray.length !== 0) {
fArray.removeAt(0)
}
2nd method
this.form.setControl('blocks', this._formB.array([]));
我遇到了类似的问题,在更新表单后我会收到上述错误,经过大量调查和失败的实验,我发现this.myForm.updateValueAndValidity
终于成功了。
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