问题描述
我正在Angular 2项目中，通过单击按钮可以动态创建输入字段.我正在同样的FormArray的帮助.字段的创建和数据提交工作正常，但是当我尝试使用一些预定义的数据填充字段时，则无法正常工作.我为我的问题制作了一个塞子. https://plnkr.co/edit/PCFD43GK91zo2ivQ9lf7?p=preview 在这里，我想用对象itemData中的数据填充视图上的字段.为便于参考，以下是Angular代码-
I am working on an Angular 2 project where I am creating input fields dynamically on button click. I am taking the help of FormArray for the same. The creation of fields and data submission is working fine but when I am trying to populate the fields with some pre-defined data then it doesn't work. I have created a plunker for my issue.https://plnkr.co/edit/PCFD43GK91zo2ivQ9lf7?p=previewHere I want to populate the fields on the view with the data in the object itemData. For easy reference, following is Angular code -
//our root app component
import { Component, NgModule } from '@angular/core'
import { BrowserModule } from '@angular/platform-browser'
import { FormBuilder, FormGroup, Validators, FormArray, FormControl } from '@angular/forms';
import { FormsModule, ReactiveFormsModule } from '@angular/forms';
@Component({
selector: 'my-app',
template: `<hr>
<div>
<form [formGroup]="orderForm" (ngSubmit)="OnSubmit(orderForm.value)">
<div>
<div>
<label>Customer Name</label>
<input type="text" formControlName="customerName"/>
<small *ngIf="IsValidField('customerName')" class="text-danger">
Customer Name is required
</small>
</div>
<br/>
<div>
<label>Customer Email</label>
<input type="text" formControlName="email"/>
<small *ngIf="IsValidField('email')" class="text-danger">
Email is required
</small>
</div>
</div>
<br/>
<div formArrayName="items" *ngFor="let item of items.controls; let i = index;">
<div [formGroupName]="i">
<div>
<label>Item Name</label>
<input type="text" formControlName="name" placeholder="Item name"/>
<small *ngIf="IsValidField('name',i)" class="text-danger">
Item Name is required
</small>
</div>
<br/>
<div>
<label>Item Description</label>
<input type="text" formControlName="description" placeholder="Item description"/>
<small *ngIf="IsValidField('description',i)" class="text-danger">
Description is required
</small>
</div>
<br/>
<div>
<label>Item Price</label>
<input type="text" formControlName="price" placeholder="Item price"/>
<small *ngIf="IsValidField('price',i)" class="text-danger">
Price is required
</small>
</div>
<br/>
</div>
</div>
<button type="submit">Save</button>
<button type="button" (click)="addItem()">Add More</button>
<button type="button" (click)="loadItems()">Load Items</button>
</form>
<div>`,
})
export class App {
constructor(private formBuilder: FormBuilder) { }
public orderForm: FormGroup;
public formSubmitAttempt: boolean;
public itemData:any=`{
"customerName":"Customer 1","email":"[email protected]",
"items":[{"name":"Item 1","description":"Item 1 Descr","price":"100"},
{"name":"Item 2","description":"Item 2 Descr","price":"200"},
{"name":"Item 3","description":"Item 3 Descr","price":"300"}]
}`;
ngOnInit() {
this.orderForm = this.formBuilder.group({
customerName: ['',[Validators.required]],
email: ['',[Validators.required]],
items: this.formBuilder.array([ this.createItem()])
});
}
createItem(): FormGroup {
return this.formBuilder.group({
name: ['',[Validators.required,Validators.maxLength(10)]],
description: '',
price: ['',[Validators.required,Validators.pattern("[(0-9)]*")]]
});
}
public loadItems(){
this.orderForm = this.formBuilder.group({
customerName: [this.itemData.customerName,[Validators.required]],
email: [this.itemData.email,[Validators.required]],
items: this.itemData.items
});
}
get items(): FormArray {
return this.orderForm.get('items') as FormArray;
};
addItem(): void {
this.items.push(this.createItem());
}
public OnSubmit(formValue: any) {
this.formSubmitAttempt = true;
console.log(JSON.stringify(formValue));
}
public IsValidField(field: string, i?:number) {
if(i!=null) {
var f = this.orderForm
.get('items') //retrieve items FormArray
.get(i.toString()) //retrieve items FormGroup
.get(field); //retrieve items form field
return (f.invalid && f.touched) || (f.invalid && this.formSubmitAttempt);
} else {
return (this.orderForm.get(field).invalid && this.orderForm.get(field).touched) || (this.orderForm.get(field).invalid && this.formSubmitAttempt);
}
}
}
@NgModule({
imports: [ BrowserModule, FormsModule, ReactiveFormsModule ],
declarations: [ App ],
bootstrap: [ App ]
})
export class AppModule {}
任何帮助将不胜感激.谢谢.
Any help would be appreciated. Thanks.
推荐答案
formArray中的元素必须是formGroups，而不仅仅是对象.
The elements inside a formArray has to be formGroups, not just an object.
在尝试为formArray分配默认值时，通过已经具有的createItems函数运行this.itemData.items.
Run your this.itemData.items through the createItems function you already have when trying to assign default values to your formArray.
public loadItems(){
this.orderForm.patchValue({
customerName: this.itemData.customerName,
email: this.itemData.email
});
this.itemData.forEach((item) => {
(<FormArray>this.orderForm.get('items')).push(this.createItem(item));
});
}
当数据来自服务时，无需重新创建表单，只需patchValues并相应地更新表单.
No need to recreate the form when data comes from a service, just patchValues and update form accordingly.
PS:您需要修改createItems以获取一些输入数据并返回带有数据的formGroup.
PS: you need to modify createItems to take some input data and return the formGroup with data.
这篇关于在Angular 2中用数据填充动态表单控件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！