有没有办法制作双向绑定输入组件,也可以在组件内部进行验证？
我想要实现的是拥有一个我可以在我的表单中排列的组件,如下所示：
<form #f="ngForm">
<my-form-input [(inputModel)]="name" [inputField]="myFormInputName"></my-form-input>
<my-form-input [(inputModel)]="name2" [inputField]="myFormInputName2"></my-form-input>
...
<my-form-input [(inputModel)]="lastItem" [inputField]="lastItemName"></my-form-input>
</form>
我有以下设置,无法弄清楚,如何使其正确：
组件：
import {Component,Input,Output,EventEmitter} from 'angular2/core'
import {FORM_DIRECTIVES} from 'angular2/common';
@Component({
selector: 'my-form-input',directives: [FORM_DIRECTIVES],template:
`
<input type="text" class="form-control" id="i1" required [ngModel]="inputModel" (ngModelChange)="onChangeInput($event)" ngControl="ctrl" #ctrl="ngForm"/>
<p>{{"Is field valid? I would like to make some decisions here depending on that: "+ctrl.valid}}</p>
`
})
export class InputComponent {
constructor(){};
@Input() inputField:string;
@Input() inputModel: Object;
@Output() inputModelChange = new EventEmitter();
onChangeInput(event){
this.inputModel=event;
this.inputModelChange.emit(event);
}
}
该应用程序：
//our root app component
import {Component} from 'angular2/core'
import {FORM_DIRECTIVES} from 'angular2/common';
import {InputComponent} from './my.input'
@Component({
selector: 'my-app',providers: [],template: `
<div>
<p>Is there a way to make a custom 2 way binding form input component having also validation?</p>
<form #f="ngForm">
<my-form-input [(inputModel)]="name" [inputField]="myFormInputName"></my-form-input>
<p>{{name}}</p>
</form>
</div>
`,directives: [InputComponent,FORM_DIRECTIVES]
})
export class App {
constructor() {
this.name = 'Angular2'
}
}
我还制作了一个Plunker来解决我的问题：http://plnkr.co/edit/0vXjHbQmv7v7EKQcLWaa?p=preview
您可以将表单控件传递给组件,以便为输入创建专用控件.基于此新控件在有效属性为false时显示错误：
@Component({
selector: 'my-form-input',template: `
<input type="text" class="form-control" id="i1"
[ngModel]="inputModel"
(ngModelChange)="onChangeInput($event)"
[ngFormControl]="formCtrl.controls[inputField]"/>
<p>Is field valid? I would like to make some decisions
here depending on that: {{formCtrl.controls[inputField].valid}}
</p>
`
})
export class InputComponent implements OnInit {
@Input() inputField:string;
@Input() formCtrl;
@Input() inputModel: Object;
@Output() inputModelChange = new EventEmitter();
ngOnInit() {
this.formCtrl.control.addControl(
this.inputField,new Control('',Validators.required));
}
onChangeInput(event){
this.inputModel=event;
this.inputModelChange.emit(event);
}
}
您需要使用addControl方法使整个表单的状态与您在输入组件中创建的控件一致.
在您的情况下,使用ngControl指令定义控件内联.我做了一些测试,但我不能这样做……
以下是从父组件中使用此组件的方法：
@Component({
selector: 'my-app',template: `
<form #f="ngForm">
<my-form-input [(inputModel)]="name" [inputField]="myFormInputName" [formCtrl]="f"></my-form-input>
</form>
`,directives: [ FORM_DIRECTIVES,InputComponent ]
})
export class AppComponent {
}
刚开始后它仍然是一个检查问题.表单的全局状态未更新,发生以下错误：
Expression '
Valid : {{f.valid}} in AppComponent@1:24' has changed after it was checked. PrevIoUs value: '
Valid : true'. Current value: '
Valid : false'
要解决这个问题,请查看基于ChangeDetectorRef类及其detectChanges方法的Julien的答案……
这是一个样本plunkr：https://plnkr.co/edit/Z4uOUq2q4iXdpo0J6R1o?p=preview.
