我正在使用 Angular2 开发一个应用程序。我正在尝试在我的应用程序中使用 Reactive Forms，但我遇到了一些错误：
第一个错误是关于 NgControl 的，如下所示：
NgControl 没有提供程序 ("
div class="col-md-8" [ERROR ->]input class="form-control" id="productNameId" "): ProductEditComponent@16:24
第二个错误是关于 ControlContainer 的，如下所示：
ControlContainer 没有提供程序 (" div [ERROR ->]div formArrayName="tags">
div 类="行">
按钮 cl"):
Htmm 文件如下：
<div class="panel panel-primary">
<div class="panel-heading">
{{pageTitle}}
</div>
<div class="panel-body">
<form class="form-horizontal"
novalidate
(ngSubmit)="saveProduct()"
formGroup="productForm" >
<fieldset>
<div class="form-group"
[ngClass]="{'has-error': displayMessage.productName }">
<label class="col-md-2 control-label" for="productNameId">Product Name</label>
<div class="col-md-8">
<input class="form-control"
id="productNameId"
type="text"
placeholder="Name (required)"
formControlName="productName" />
<span class="help-block" *ngIf="displayMessage.productName">
{{displayMessage.productName}}
</span>
</div>
</div>
<div formArrayName="tags">
<div class="row">
<button class="col-md-offset-1 col-md-1 btn btn-default"
type="button"
(click)="addTag()">Add Tag
</button>
</div>
<div class="form-group"
*ngFor="let tag of tags.controls; let i=index" >
<label class="col-md-2 control-label" [attr.for]="i">Tag</label>
<div class="col-md-8">
<input class="form-control"
[id]="i"
type="text"
placeholder="Tag"
formControlName="i" />
</div>
</div>
</div>
<!--more piece of code here -->
我的组件文件如下：
import { Component, OnInit, AfterViewInit, OnDestroy, ViewChildren, ElementRef } from '@angular/core';
import { FormBuilder, FormGroup, FormControl, FormArray, Validators, FormControlName,NgForm } from '@angular/forms';
import { ActivatedRoute, Router } from '@angular/router';
import 'rxjs/add/operator/debounceTime';
import 'rxjs/add/observable/fromEvent';
import 'rxjs/add/observable/merge';
import { Observable } from 'rxjs/Observable';
import { Subscription } from 'rxjs/Subscription';
import { IProduct } from './product';
import { ProductService } from './product.service';
import { NumberValidators } from '../shared/number.validator';
import { GenericValidator } from '../shared/generic-validator';
@Component({
templateUrl: './product-edit.component.html'
})
export class ProductEditComponent implements OnInit, AfterViewInit, OnDestroy {
@ViewChildren(FormControlName, { read: ElementRef }) formInputElements: ElementRef[];
pageTitle: string = 'Product Edit';
errorMessage: string;
productForm: FormGroup;
product: IProduct;
private sub: Subscription;
// Use with the generic validation message class
displayMessage: { [key: string]: string } = {};
private validationMessages: { [key: string]: { [key: string]: string } };
private genericValidator: GenericValidator;
get tags(): FormArray {
return <FormArray>this.productForm.get('tags');
}
constructor(private fb: FormBuilder,
private route: ActivatedRoute,
private router: Router,
private productService: ProductService) {
// Defines all of the validation messages for the form.
// These could instead be retrieved from a file or database.
this.validationMessages = {
productName: {
required: 'Product name is required.',
minlength: 'Product name must be at least three characters.',
maxlength: 'Product name cannot exceed 50 characters.'
},
productCode: {
required: 'Product code is required.'
},
starRating: {
range: 'Rate the product between 1 (lowest) and 5 (highest).'
}
};
// Define an instance of the validator for use with this form,
// passing in this form's set of validation messages.
this.genericValidator = new GenericValidator(this.validationMessages);
}
ngOnInit(): void {
this.productForm = this.fb.group({
productName: ['', [Validators.required,
Validators.minLength(3),
Validators.maxLength(50)]],
productCode: ['', Validators.required],
starRating: ['', NumberValidators.range(1, 5)],
tags: this.fb.array([]),
description: ''
});
// Read the product Id from the route parameter
this.sub = this.route.params.subscribe(
params => {
let id = +params['id'];
this.getProduct(id);
}
);
}
ngOnDestroy(): void {
this.sub.unsubscribe();
}
ngAfterViewInit(): void {
// Watch for the blur event from any input element on the form.
let controlBlurs: Observable<any>[] = this.formInputElements
.map((formControl: ElementRef) => Observable.fromEvent(formControl.nativeElement, 'blur'));
// Merge the blur event observable with the valueChanges observable
Observable.merge(this.productForm.valueChanges, ...controlBlurs).debounceTime(800).subscribe(value => {
this.displayMessage = this.genericValidator.processMessages(this.productForm);
});
}
addTag(): void {
this.tags.push(new FormControl());
}
getProduct(id: number): void {
this.productService.getProduct(id)
.subscribe(
(product: IProduct) => this.onProductRetrieved(product),
(error: any) => this.errorMessage = <any>error
);
}
onProductRetrieved(product: IProduct): void {
if (this.productForm) {
this.productForm.reset();
}
this.product = product;
if (this.product.id === 0) {
this.pageTitle = 'Add Product';
} else {
this.pageTitle = `Edit Product: ${this.product.productName}`;
}
// Update the data on the form
this.productForm.patchValue({
productName: this.product.productName,
productCode: this.product.productCode,
starRating: this.product.starRating,
description: this.product.description
});
this.productForm.setControl('tags', this.fb.array(this.product.tags || []));
}
deleteProduct(): void {
if (this.product.id === 0) {
// Don't delete, it was never saved.
this.onSaveComplete();
} else {
if (confirm(`Really delete the product: ${this.product.productName}?`)) {
this.productService.deleteProduct(this.product.id)
.subscribe(
() => this.onSaveComplete(),
(error: any) => this.errorMessage = <any>error
);
}
}
}
saveProduct(): void {
if (this.productForm.dirty && this.productForm.valid) {
// Copy the form values over the product object values
let p = Object.assign({}, this.product, this.productForm.value);
this.productService.saveProduct(p)
.subscribe(
() => this.onSaveComplete(),
(error: any) => this.errorMessage = <any>error
);
} else if (!this.productForm.dirty) {
this.onSaveComplete();
}
}
onSaveComplete(): void {
// Reset the form to clear the flags
this.productForm.reset();
this.router.navigate(['/products']);
}
}
我试图解决这个问题超过 2 天，但我仍然没有解决方案。我在stackoverflow中看到了许多其他答案，但没有一个能解决我的问题。