Angular 2 FormGroup添加验证器动态 [英] Angular 2 FormGroup Add Validators dynamic

问题描述

我正在尝试向FormContol动态添加验证器(不适用于初始化)，并且不起作用....

代码:

 this.formGroup.controls["firstName"].validator = Validators.Required; 

有人做吗?

解决方案

尝试一下，它应该可以工作

this.formGroup.controls["firstName"].setValidators(Validators.required);

用于多个验证人

this.formGroup.controls["firstName"].setValidators([Validators.required, Validators.minLength(2)]);

但是这样做会覆盖初始化期间提供的所有验证器

编辑:

要立即用新添加的Validators反映表单控件，我们必须在动态设置验证器之后调用this.formGroup.controls["firstName"].updateValueAndValidity();.

this.formGroup.controls["firstName"].setValidators(Validators.required);
this.formGroup.controls["firstName"].updateValueAndValidity();

演示 >

*注意*

即使值没有真正改变，

updateValueAndValidity()也会触发一个valueChanges事件(如果从valueChanges订阅中调用它，则可能导致无限循环).您可以通过使用可选的参数对象来阻止这种情况:{onlySelf:true，酋长:false}

i'm tring to add validator to FormContol dynamic (not on initialization) and it's not work....

the code:

this.formGroup.controls["firstName"].validator = Validators.Required;

Did anyone do it?

解决方案

Try this, it should work

this.formGroup.controls["firstName"].setValidators(Validators.required);

For multiple validators

this.formGroup.controls["firstName"].setValidators([Validators.required, Validators.minLength(2)]);

But doing so will override any validators that are provided during initialization

EDIT :

To reflect the form controls with newly added Validators immediately, we have to call this.formGroup.controls["firstName"].updateValueAndValidity(); after setting validators dynamically.

this.formGroup.controls["firstName"].setValidators(Validators.required);
this.formGroup.controls["firstName"].updateValueAndValidity();

DEMO for the same

* NOTE *

updateValueAndValidity() will trigger a valueChanges event even if the value didn't really change (potentially resulting in an infinite loop, if you're calling it from within a valueChanges subscription). You can prevent that by using the optional parameter object: { onlySelf: true, emitEvent: false}

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