在Angular中，如何在创建控件后将Validator添加到FormControl? [英] In Angular, how to add Validator to FormControl after control is created?

问题描述

我们有一个具有动态生成表单的组件.添加带有验证器的控件的代码可能如下所示:

We have a component that has a dynamically built form. The code to add a control with validators might look like this:

var c = new FormControl('', Validators.required);

但是，假设我要添加第二个验证器稍后.我们怎样才能做到这一点?我们无法在此在线找到任何文档.我确实发现，虽然在表单控件中有setValidators

But let's say that I want to add 2nd Validator later. How can we accomplish this? We cannot find any documentation on this online. I did find though in the form controls there is setValidators

this.form.controls["firstName"].setValidators 

，但不清楚如何添加新的或自定义的验证器.

but it is not clear how to add a new or custom validator.

推荐答案

您只需向FormControl传递一个验证器数组.

You simply pass the FormControl an array of validators.

下面是一个示例，显示如何将验证器添加到现有FormControl:

Here's an example showing how you can add validators to an existing FormControl:

this.form.controls["firstName"].setValidators([Validators.minLength(1), Validators.maxLength(30)]);

注意，这将重置在创建FormControl时添加的所有现有验证器.

Note, this will reset any existing validators you added when you created the FormControl.

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