这种情况
我试图在我的Angular应用程序中创建一个非常简单的表单，但无论如何，它都无法工作。
Angular版本
Angular 2.0.0 RC5
这个错误
不能绑定到'formGroup'因为它不是'form'的已知属性
的代码
视图
<form [formGroup]="newTaskForm" (submit)="createNewTask()">
<div class="form-group">
<label for="name">Name</label>
<input type="text" name="name" required>
</div>
<button type="submit" class="btn btn-default">Submit</button>
</form>
控制器
import { Component } from '@angular/core';
import { FormGroup, FormControl, Validators, FormBuilder } from '@angular/forms';
import {FormsModule,ReactiveFormsModule} from '@angular/forms';
import { Task } from './task';
@Component({
selector: 'task-add',
templateUrl: 'app/task-add.component.html'
})
export class TaskAddComponent {
newTaskForm: FormGroup;
constructor(fb: FormBuilder)
{
this.newTaskForm = fb.group({
name: ["", Validators.required]
});
}
createNewTask()
{
console.log(this.newTaskForm.value)
}
}
《ngModule
import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { FormsModule } from '@angular/forms';
import { routing } from './app.routing';
import { AppComponent } from './app.component';
import { TaskService } from './task.service'
@NgModule({
imports: [
BrowserModule,
routing,
FormsModule
],
declarations: [ AppComponent ],
providers: [
TaskService
],
bootstrap: [ AppComponent ]
})
export class AppModule { }
这个问题
为什么会出现这个错误?我遗漏了什么吗?
如果你在开发一个组件时遇到了这个问题，你应该把这两个模块添加到你最近的模块中:
import { FormsModule, ReactiveFormsModule } from '@angular/forms';
@NgModule({
declarations: [
AppComponent
],
imports: [
// other modules
FormsModule,
ReactiveFormsModule
],
providers: [],
bootstrap: [AppComponent]
})
export class AppModule { }
如果你正在为你的组件开发一个测试，那么你应该像这样将这个模块添加到你的测试文件中:
import { async, ComponentFixture, TestBed } from '@angular/core/testing';
import { ContactusComponent } from './contactus.component';
import { ReactiveFormsModule } from '@angular/forms';
describe('ContactusComponent', () => {
let component: ContactusComponent;
let fixture: ComponentFixture<ContactusComponent>;
beforeEach(async(() => {
TestBed.configureTestingModule({
declarations: [ContactusComponent],
imports:[
ReactiveFormsModule
]
})
.compileComponents();
}));
beforeEach(() => {
fixture = TestBed.createComponent(ContactusComponent);
component = fixture.componentInstance;
fixture.detectChanges();
});
it('should create', () => {
expect(component).toBeTruthy();
});
});
你的Angular版本是11+，你使用的是VisualStudioCode?
你已经导入了FormsModule, ReactiveFormsModule，并将其添加到app.module.ts的import -section中(相关模块可能不同，请选择正确的模块):
// app.module.ts (excerpt)
import { FormsModule, ReactiveFormsModule } from '@angular/forms';
imports: [
...
FormsModule,
ReactiveFormsModule,
...
],
您有正确的导入(有时还有其他具有类似名称的库);您已经在组件中定义并初始化了表单吗?
// MyWonderfulComponent (excerpt)
import { FormBuilder, FormGroup, Validators } from '@angular/forms';
export class MyWonderfulComponent implements OnInit {
form: FormGroup;
...
constructor (private fb: FormBuilder) {
this.form = this.fb.group({
// DON'T FORGET THE FORM INITIALISATION
});
}
你的组件模板有你的表单:
<form [formGroup]="form" (ngSubmit)="submit()">
<!-- MY FORM CONTROLS ARE ALREADY HERE -->
</form>
您仍然会收到错误消息“…因为它不是已知的……”?
然后只需简单地重新启动VisualStudioCode:)
