不能绑定到formControl'因为它不是'输入&#39的已知属性;Angular2材质自动补全问题

我正在尝试在我的Angular 2项目中使用Angular Material 自动完成组件。我将以下内容添加到模板中。

<md-input-container>
<input mdInput placeholder="Category" [mdAutocomplete]="auto" [formControl]="stateCtrl">
</md-input-container>


<md-autocomplete #auto="mdAutocomplete">
<md-option *ngFor="let state of filteredStates | async" [value]="state">
{{ state }}
</md-option>
</md-autocomplete>

下面是我的组件。

import {Component, OnInit} from "@angular/core";
import {ActivatedRoute, Router} from "@angular/router";
import {FormControl} from "@angular/forms";


@Component({
templateUrl: './edit_item.component.html',
styleUrls: ['./edit_item.component.scss']
})
export class EditItemComponent implements OnInit {
stateCtrl: FormControl;
states = [....some data....];


constructor(private route: ActivatedRoute, private router: Router) {
this.stateCtrl = new FormControl();
this.filteredStates = this.stateCtrl.valueChanges.startWith(null).map(name => this.filterStates(name));
}
ngOnInit(): void {
}
filterStates(val: string) {
return val ? this.states.filter((s) => new RegExp(val, 'gi').test(s)) : this.states;
}
}

我得到如下错误。看起来formControl指令没有被找到。

不能绑定到'formControl'因为它不是'input'的已知属性

这里的问题是什么?

313940 次浏览
小开
最佳答案

在使用formControl时，必须将ReactiveFormsModule导入到imports数组中。

例子:

import {FormsModule, ReactiveFormsModule} from '@angular/forms';


@NgModule({
imports: [
BrowserModule,
FormsModule,
ReactiveFormsModule,
MaterialModule,
],
...
})
export class AppModule {}
小开

忘记试图破译示例.ts -因为其他人说它通常是不完整的。

相反，只需点击这里圈起来的“弹出”图标，你就会得到一个完整的StackBlitz示例。

enter image description here

您可以快速确认所需模块:

enter image description here

注释掉ReactiveFormsModule的任何实例，当然你会得到错误:

Template parse errors:
Can't bind to 'formControl' since it isn't a known property of 'input'.
小开

首先在模板中添加一个普通的matInput。让我们假设您正在使用ReactiveFormsModule中的formControl指令来跟踪输入的值。

响应式表单提供了一种模型驱动的方法来处理值随时间变化的表单输入。本指南向您展示如何创建和更新简单表单控件，如何在组中使用多个控件，如何验证表单值，以及如何实现更高级的表单。

import { FormsModule, ReactiveFormsModule } from "@angular/forms"; //this to use ngModule

.．.

imports: [
BrowserModule,
AppRoutingModule,
HttpModule,
FormsModule,
RouterModule,
ReactiveFormsModule,
BrowserAnimationsModule,
MaterialModule],
小开

从9.1.4版本开始，你只需要导入ReactiveFormsModule

< a href = " https://angular。Io /guide/reactive-forms" rel="nofollow noreferrer">https://angular.io/guide/reactive-forms

小开

出现这种情况的另一个原因是:

你在其中使用formControl的组件并没有在导入ReactiveFormsModule. 0的模块中声明。

因此，请检查声明抛出此错误的组件的模块。

小开
在angular 12中，matautocompleteModule的import路径被改变了 解决了我的问题……现在是这样的 enter image description here < / p >
小开

对我来说有用的是在@component({})的模板中构建表单，例如——


import { Component, OnInit } from '@angular/core';
import { FormControl } from '@angular/forms';


@Component({
selector: 'app-contact-form',
template:`
<form class="validation-form" validate method="createUserWithEmailAndPassword">
<div class="form-row">
<div class="col-md-6 mb-3">
<label for="firstName">First name</label>
<input type="text" [formControl]="firstName" id="firstName" placeholder="Please enter your first name" required>
<div class="valid-feedback">
Looks good!
</div>
</div>
<div class="col-md-6 mb-3">
<label for="lastName">Last name</label>
<input type="text" [formControl]="lastName" id="lastName" placeholder="Please enter your last name" required>
<div class="valid-feedback">
Looks good!
</div>
</div>
</div>
<div class="form-row">
<div class="col-md-6 mb-3">
<label for="email">Email address</label>
<input type="email" [formControl]="email" id="email" aria-describedby="emailHelp" placeholder="Please enter your last name" required>
<small id="emailHelp" class="form-text text-muted">We'll never share your email with anyone else.</small>
<div class="valid-feedback">
Looks good!
</div>
</div>
</div>
<div class="col-md-6 mb-3">
<label for="password">Password</label>
<input type="password" [formControl]="password" id="password" placeholder="Please enter your password" required>
<div class="valid-feedback">
Looks good!
</div>
</div>
<div class="col-md-3 mb-3">
<label for="zip">Zip</label>
<input type="text" [formControl]="zip" id="zip" required>
<div class="invalid-feedback">
Please provide a valid zip.
</div>
</div>
</div>
<div class="form-group">
<div class="form-check">
<input class="form-check-input" type="checkbox" value="" id="invalidCheck" required>
<label class="form-check-label" for="invalidCheck">
Agree to terms and conditions
</label>
<div class="invalid-feedback">
You must agree before submitting.
</div>
</div>
</div>
<button class="btn btn-primary" type="submit">Submit form</button>
</form>`,


templateUrl: './contact-form.component.html',
styleUrls: ['./contact-form.component.scss']
})
export class ContactFormComponent implements OnInit {


firstName =  new FormControl('');
lastName =  new FormControl('');
email =  new FormControl('');
password =  new FormControl('');


constructor() { }


ngOnInit(): void {
}


}

这停止显示错误。如果错误仍然存在，那么这可以为您解决问题

小开

对我有用的是将我的导入移动到之前我的声明和导出，不知道为什么这样做，但它做到了…

@NgModule({
imports: [
CommonModule,
FormsModule,
ReactiveFormsModule,
MatSlideToggleModule,
],
declarations: [SettingsComponent],
exports: [
SettingsComponent
]
})
export class SettingsModule { }

提交答案