Javascript 错误:在使用API文档时,mat表单字段必须包含MATFORMFIREDCONTROL?

Javascript 错误:在使用API文档时,mat表单字段必须包含MATFORMFIREDCONTROL?,javascript,angular,typescript,angular-material,angular-material-8,Javascript,Angular,Typescript,Angular Material,Angular Material 8,我像这样导入了MatFormFieldModule: import { BrowserModule } from '@angular/platform-browser'; import { NgModule } from '@angular/core'; import { AppRoutingModule } from './app-routing.module'; import { AppComponent } from './app.component';

我像这样导入了
MatFormFieldModule

    import { BrowserModule } from '@angular/platform-browser';
    import { NgModule } from '@angular/core';

    import { AppRoutingModule } from './app-routing.module';
    import { AppComponent } from './app.component';
    import { BrowserAnimationsModule } from '@angular/platform-browser/animations';
    //import { MaterialModule } from './material/material.module';
    import {MatFormFieldModule} from '@angular/material/form-field';

    @NgModule({
      declarations: [
        AppComponent
      ],
      imports: [
        BrowserModule,
        AppRoutingModule,
        BrowserAnimationsModule,
    //    MaterialModule,
        MatFormFieldModule
      ],
      providers: [],
      bootstrap: [AppComponent]
    })
    export class AppModule { }
app.component.html
中,我已经(直接取自API文档):


您还应导入
MatInputModule

import {MatInputModule} from '@angular/material/input';

@NgModule({
  imports: [
    MatFormFieldModule,
    MatInputModule,
    ...
  ]
})
否则Angular不知道如何初始化
的指令,这与:?
ERROR Error: mat-form-field must contain a MatFormFieldControl.
import {MatInputModule} from '@angular/material/input';

@NgModule({
  imports: [
    MatFormFieldModule,
    MatInputModule,
    ...
  ]
})
@Directive({
  selector: `input[matInput], textarea[matInput], select[matNativeControl],
      input[matNativeControl], textarea[matNativeControl]`,
  ...
  providers: [{provide: MatFormFieldControl, useExisting: MatInput}],
})