角度错误:NodeInjector:NOT_FOUND [ControlContainer] [英] Angular Error: NodeInjector: NOT_FOUND [ControlContainer]

问题描述

core.js:5873错误错误:NodeInjector:NOT_FOUND [ControlContainer]

core.js:5873 ERROR Error: NodeInjector: NOT_FOUND [ControlContainer]

有时，当我重新启动项目时，它可以完美运行.app.component.html中只有更改:

Sometimes when I restart the project it runs perfectly. There are only changes in app.component.html :

<div class="container">
  <div class="row">
    <div class="col-md-4">
      <form action="">

        <div class="form-group">
          <label for="">Username</label>
          <input type="text" name="username" class="form-control" />
        </div>
        <div class="form-group">
          <label>Password</label>
          <input type="password" class="form-control">
        </div>
        <div class="form-group">
          <label>Confirm Password</label>
          <input type="password" class="form-control">
        </div>
        <div>
          <button type="submit" class="btn btn-primary btn-block">Register</button>
        </div>
      </form>
      
    </div>
  </div>
</div>

推荐答案

在 app.module.ts 中，我在 imports 中添加了 ReactiveFormsModule 部分.记住要在顶部将其导入为:从'@ angular/forms 导入 import {ReactiveFormsModule}.

In app.module.ts I add ReactiveFormsModule in my imports section. Remember to import it at the top as: import { ReactiveFormsModule} from '@angular/forms.

在您的 app.component.ts 中，您必须定义 FormGroup 实例，并通过 ngOnInit 方法对其进行初始化/注册，如下所示:

In your app.component.ts you have to define FormGroup instance and initialize/register it via ngOnInit method as below:

    import { FormGroup, FormControl } from '@angular/forms'; //imports
.......................................................................
    myForm:FormGroup;  
    ngOnInit(){
         this.myForm = new FormGroup({          
               'name':new FormControl(null), //note, can have up to 3 Constructor Params: default value, validators, AsyncValidators
               'email':new FormControl(null,Validators.email)

          })
    }

然后将表单绑定到 FormGroup 实例 myForm :

Then bind form to the FormGroup instance myForm:

<form [formGroup]="myForm">

请注意， name 和 email 是需要使用 formControlName 绑定的表单中的控件:

Note that name and email are controls in the form that needs binding using formControlName :

<input type="text" name="name" formControlName="name">

这篇关于角度错误:NodeInjector:NOT_FOUND [ControlContainer]的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！