使用ngControl造成錯誤：沒有提供程序ControlContainer

Question

我試圖使用ngControl首次在我的應用程序：

<md-input placeholder="Amount" value="0" ngControl="ammount" required></md-input> 

添加了以下在我的組件：

import { FORM_PROVIDERS,FORM_DIRECTIVES } from '@angular/common'; 

.. 

directives: [MD_INPUT_DIRECTIVES, 
    FORM_DIRECTIVES, 
    ], 
    providers: [FORM_PROVIDERS], 

和我得到這個錯誤：

browser_adapter.ts:78 EXCEPTION: Error: Uncaught (in promise): Template parse errors: 
No provider for ControlContainer (" 

[ERROR ->]<md-input placeholder="Amount" value="0" ngControl="ammount" required></md-input> 

我在想什麼？

Answer 1

我認爲你忘了包裹md-input成分form標籤，否則ngControl將無法​​正常工作：

<form> 
    ... 
    <md-input placeholder="Amount" value="0" ngControl="ammount" required></md-input> 
    ... 
</form> 

This directive can only be used as a child of NgForm or NgFormModel.

Answer 2

爲了解決這個問題，你有兩個選擇： A.在main.ts：

import {FORM_PROVIDERS} from 'angular2/common'; 

// other code here 

bootstrap(AppCmp, [ 
    ROUTER_PROVIDERS, 
    provide(LocationStrategy, { useClass: HashLocationStrategy }), 
    FORM_PROVIDERS 
]); 

B.在組件使用形式：

import {FORM_PROVIDERS, FORM_DIRECTIVES} from 'angular2/common'; 
@Component({ 
    providers: [FORM_PROVIDERS], 
    directives: [FORM_DIRECTIVES] 
}) 

從這些相同的問題而採取的在github上

• https://github.com/mgechev/angular2-seed/issues/399

• https://github.com/angular/angular/issues/6374

可以幫你。