Unexpected value 'MatDialogRef' imported by the module 'AppModule'. Please add a @NgModule annotation

Question

I am trying to integrate Angular Material in Angular but getting following error. The program is compiled successfully but getting this issue in browser.

Uncaught Error: Unexpected value 'MatDialogRef' imported by the module 'AppModule'. Please add a @NgModule annotation.
    at syntaxError (compiler.js:485)
    at eval (compiler.js:15226)
    at Array.forEach (<anonymous>)
    at CompileMetadataResolver.getNgModuleMetadata (compiler.js:15201)
    at JitCompiler._loadModules (compiler.js:34385)
    at JitCompiler._compileModuleAndComponents (compiler.js:34346)
    at JitCompiler.compileModuleAsync (compiler.js:34240)
    at CompilerImpl.compileModuleAsync (platform-browser-dynamic.js:239)
    at PlatformRef.bootstrapModule (core.js:5551)
    at eval (main.ts:11)

I have imported MatDialogRef in app.module.ts

import { MatDialogModule, MatDialogRef } from '@angular/material/dialog';

imports: [
    BrowserModule,
    FormsModule,
    BrowserAnimationsModule,
    MatButtonModule,
    MatDialogModule,
    MatDialogRef,
    ReactiveFormsModule,
    HttpModule,
    HttpClientModule,
    AppRoutingModule
  ],

I have also imported it in the component where dialog html is saved.

import { MatDialogRef, MAT_DIALOG_DATA } from '@angular/material';

export class ComposeMailComponent implements OnInit {

constructor(private dialogRef: MatDialogRef<ComposeMailComponent>,
      @Inject(MAT_DIALOG_DATA) private data) {}

  ngOnInit() {
  }
}

Solution 1

You dont need to import MatDialogRef inside app.module.ts, Change

From

import { MatDialogModule, MatDialogRef } from '@angular/material/dialog';

To

import { MatDialogModule} from '@angular/material';

and remove MatDialogRef from imports array

Solution 2

add these in app.module.ts file

import { MatDialogModule} from '@angular/material';

imports: [ MatDialogModule ],

it will work fine