在FormControl中更新验证器 [英] Update Validators in FormControl

问题描述

有什么方法可以在声明后更新控件，例如

is there any way to update control after it declared, like

this.input = new FormControl('', Validators.required)
this.form = this.formBuilder.group({
  input = this.input
})

this.input.update('', Validators.maxlength(20))

推荐答案

如果以后要设置新的Validator，则可以使用setValidators，您可能还希望更新其值和有效性，它可以与updateValueAndValidity一起运行.这是一个简单的示例:

You can use setValidators if you want to set new Validator(s) at a later point, you'd probably also want to update the value and validity, it can be run with updateValueAndValidity. Here's a simple example:

this.myForm.controls.input.setValidators([Validators.required, 
                                          Validators.minLength(4)]);

this.myForm.controls.input.updateValueAndValidity();

演示

如果要更新字段值，可以使用patchValue.

And if you want to update the field value, you can as mentioned use patchValue.

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