意想不到的价值＆＃39; MatSnackBar＆＃39;由模块＆＃39; AppModule＆＃39;导入。请添加@NgModule注释

Question

我想利用MatSnackBar在事件完成时显示通知。我在我的app模块中导入了MatSnackBar，下面是我的app.module.ts

...
import { MatSnackBar,
    MatSnackBarConfig, ...
} from '@angular/material';
...

@NgModule({
    declarations: [...],
    imports: [MatSnackBar, MatSnackBarConfig, ...],
    providers: [...],
    bootstrap: [...],
    entryComponents: [...]
})
export class AppModule {
}

下面是我的package.json：

{
    "@angular/animations": "^5.1.0",
    "@angular/cdk": "^5.0.0",
    "@angular/cli": "^1.6.1",
    "@angular/common": "^5.1.0",
    "@angular/compiler": "^5.1.0",
    "@angular/compiler-cli": "^5.1.0",
    "@angular/core": "^5.1.0",
    "@angular/forms": "^5.1.0",
    "@angular/http": "^5.1.0",
    "@angular/language-service": "^5.1.0",
    "@angular/material": "^5.0.0",
    "@angular/platform-browser": "^5.1.0",
    "@angular/platform-browser-dynamic": "^5.1.0",
    "@angular/router": "^5.1.0",
    "@swimlane/ngx-charts": "^7.0.1",
    "@types/jasmine": "^2.8.2",
    "@types/jasminewd2": "^2.0.3",
    "@types/node": "^8.0.56",
    "angular2-datatable": "^0.6.0",
    "core-js": "^2.5.1",
    "d3": "^4.10.0",
    "ng-http-loader": "^0.2.0",
    "ng2-charts": "^1.6.0",
    "ng2-handsontable": "^1.0.3",
    "rxjs": "^5.5.5",
    "zone.js": "^0.8.18"
}

以下是我得到的错误：

compiler.js:485 Uncaught Error: Unexpected value 'MatSnackBar' imported by the module 'AppModule'. Please add a @NgModule annotation.
    at syntaxError (compiler.js:485)
    at eval (compiler.js:15206)
    at Array.forEach (<anonymous>)
    at CompileMetadataResolver.getNgModuleMetadata (compiler.js:15189)
    at JitCompiler._loadModules (compiler.js:34226)
    at JitCompiler._compileModuleAndComponents (compiler.js:34187)
    at JitCompiler.compileModuleAsync (compiler.js:34081)
    at CompilerImpl.compileModuleAsync (platform-browser-dynamic.js:230)
    at PlatformRef.bootstrapModule (core.js:5573)
    at eval (main.ts:11)

我使用角度材料5.0.0，我是否需要使用其他版本才能使用MatSnackBar？

Answer 1

您需要导入

import { MatSnackBarModule } from "@angular/material";

并在导入

下添加

@NgModule({
    imports: [
        MatSnackBarModule,
    ],
    providers: [

    ],
})

参考 issue

Answer 2

这是对我有用的东西
（在出现诸如File 'angular/app/node_modules/@angular/material/index.d.ts' is not a module.

之类的导入错误之前

1. 在MatSnackBarModule中导入app.module.ts ：

   import { NgModule } from '@angular/core';
   import { MatSnackBarModule } from '@angular/material/snack-bar'; // <= import the module: MatSnackBarMODULE
   
   @NgModule({
     declarations: [ 
    ],
   
    imports: [
        MatSnackBarModule,                                           // <= add it to import list
    ],
   

1. 以及使用它的地方，例如在app.component.ts中：

   import { MatSnackBar } from '@angular/material/snack-bar'; // <= ⚠️ import the class with path 'material/SNACK-BAR'
   
   // […] 
   
   export class AppComponent {
   
     constructor( private _snackbar: MatSnackBar ) {     // <= add it to constructor
     }
   
     // Use it the way you like it
     fooBar() {
   
         const snack = this._snackbar.open('Hello', 'Action');
         snack
           .onAction()
           .subscribe(() => {
             // Action...
           });
      }        
   }
   

在StackBlitz上
1. 演示！