formGroup需要一个FormGroup实例

本文介绍了formGroup需要一个FormGroup实例的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我在Plunkr上有一个Angular 2 RC4基本表单示例，该示例似乎引发以下错误（在Chrome DEV控制台中）

I have an Angular 2 RC4 basic form example on Plunkr that appears to throw the following error (In Chrome DEV console)

这里是plunkr

错误：

browser_adapter.ts:82 EXCEPTION: Error: Uncaught (in promise): EXCEPTION: Error in ./App class App - inline template:1:7
ORIGINAL EXCEPTION: formGroup expects a FormGroup instance. Please pass one in.
           Example: <form [formGroup]="myFormGroup">

ORIGINAL STACKTRACE:
Error: formGroup expects a FormGroup instance. Please pass one in.
           Example: <form [formGroup]="myFormGroup">

    at new BaseException (https://npmcdn.com/@angular/[email protected]/src/facade/exceptions.js:27:23)
    at FormGroupDirective._checkFormPresent (https://npmcdn.com/@angular/[email protected]/src/directives/reactive_directives/form_group_directive.js:110:19)
    at FormGroupDirective.ngOnChanges (https://npmcdn.com/@angular/[email protected]/src/directives/reactive_directives/form_group_directive.js:39:14)
    at DebugAppView._View_App0.detectChangesInter

推荐答案

您的代码中有一些问题

< div [formGroup] = form> 在< form> 标记之外

< form [formGroup] = form> ，但包含 FormGroup 是 loginForm ，因此应为< form [formGroup] = loginForm>

 
   [formControlName] = dob 传递属性值 dob 不存在。您需要传递字符串 dob ，例如 [formControlName] ='dob' 或更简单的 formControlName = dob

<div [formGroup]="form"> outside of a <form> tag
<form [formGroup]="form"> but the name of the property containing the FormGroup is loginForm therefore it should be <form [formGroup]="loginForm">
[formControlName]="dob" which passes the value of the property dob which doesn't exist. What you need is to pass the string dob like [formControlName]="'dob'" or simpler formControlName="dob"

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