Angular2 Reactive forms -使用下拉菜单设置表单域的默认值
Angular2 Reactive forms -使用下拉菜单设置表单域的默认值
提问于 2016-09-29 17:08:01
如何为angular 2 reactive forms中的所有表单字段设置默认值？
以下是重现该问题的plnkr
下面的代码不会更新DropDrop值，因为它有一个关联的对象。
注意:这里我需要用从后端API接收到的响应来设置所有表单字段的默认值。
Component.html
<form [formGroup]="myForm" novalidate (ngSubmit)="save(myForm.value, myForm.valid)">
<div class="form-group">
<label>Country:</label>
<select formControlName="country">
<option *ngFor="let country of masterCountries" [ngValue]="country">{{country.countryName}}</option>
</select>
</div>
<div class="form-group">
<label for="">Name</label>
<input type="text" class="form-control" formControlName="name">
<small [hidden]="myForm.controls.name.valid || (myForm.controls.name.pristine && !submitted)" class="text-danger">
Name is required (minimum 5 characters).
</small>
<!--<pre class="margin-20">{{ myForm.controls.name.errors | json }}</pre>-->
</div>
<button type="submit" class="btn btn-default">Submit</button>
<div class="margin-20">
<div>myForm details:-</div>
<pre>Is myForm valid?: <br>{{myForm.valid | json}}</pre>
<pre>Is myForm submitted?: <br>{{submitted | json}}</pre>
<pre>myForm value: <br>{{myForm.value | json}}</pre>
</div>
Component.ts
export class AppComponent implements OnInit {
public myForm: FormGroup;
public masterCountries: any[] = [{"countryCode":"AF","countryName":"Afghanistan"},{"countryCode":"AL","countryName":"Albania"},{"countryCode":"DZ","countryName":"Algeria"},{"countryCode":"AS","countryName":"American Samoa"},{"countryCode":"AD","countryName":"Andorra"}];
// Sample response received from backend api
public CountryResponse = {country: {"countryCode":"AF","countryName":"Afghanistan"}, name: 'test123'};
constructor(private _fb: FormBuilder) { }
ngOnInit() {
// the short way
this.myForm = this._fb.group({
country: [''],
name: ['', [<any>Validators.required, <any>Validators.minLength(5)]],
});
(<FormGroup>this.myForm)
.setValue(this.CountryResponse, {onlySelf: true});
}
save(model: User, isValid: boolean) {
this.submitted = true;
console.log(model, isValid);
}
}如果有其他方法来设置整个表单，请让我知道。
回答 2
Stack Overflow用户
回答已采纳
发布于 2016-09-29 18:34:56
只需更改以下内容：
(<FormGroup>this.myForm)
.setValue(this.CountryResponse, {onlySelf: true});如下所示：
const selectedCountry = this.masterCountries.find(country => country.countryCode === this.CountryResponse.country.countryCode)
this.CountryResponse.country = selectedCountry;
(<FormGroup>this.myForm)
.setValue(this.CountryResponse, {onlySelf: true});如前所述，您需要传递与该对象完全相同的引用
Stack Overflow用户
发布于 2018-01-02 15:49:42
声明窗体控件或初始化时，将默认值作为参数传递
MyFormControl: FormControl = new FormControl('Default value');页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/39766029
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