angular - NullInjectorError: No provider for MatDialogRef

Question

I can't inject MatDialogRef as it described in documentation: https://material.angular.io/components/dialog/overview

When i'm trying to do it i'v got error:

ERROR Error: StaticInjectorError[MatDialogRef]: StaticInjectorError[MatDialogRef]: NullInjectorError: No provider for MatDialogRef!

app.module.ts

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

import {
MatInputModule,
MatDialogModule,
MatProgressSpinnerModule,
MatButtonModule,
MatDialog,
MatDialogRef
} from '@angular/material';

import { ApiModule } from '../api/api.module';
import { RoutingModule } from '../routing/routing.module';

import { RegistrationComponent } from './components/registration.component';
import { LoginComponent } from './components/login.component';

import { AccountService } from './services/account.service';

@NgModule({
imports: [
BrowserModule,
MatInputModule,
MatDialogModule,
MatProgressSpinnerModule,
MatButtonModule,
FormsModule,
RoutingModule,
ApiModule
],
declarations: [
RegistrationComponent,
LoginComponent
],
entryComponents: [
LoginComponent,
RegistrationComponent
],
providers: [
AccountService,
MatDialog,
MatDialogRef
]
})
export class AccountModule {}

Answer 1

I had this error when adding dialogs to a service to be shared in many components. Just to clarify, the error wasn't present in the application before moving dialogs to the service. The solution was to include a custom provider MatDialogRef in the main module

  import {DialogService} from './services/dialog.service';
  import {MatDialogModule, MatDialogRef} from '@angular/material/dialog';
  ...
  imports: [
    ...
    MatDialogModule
  ],
  providers: [
     {
       provide: MatDialogRef,
       useValue: {}
     },
     DialogService
  ],
  ...

With this provider the service worked as a singleton with my dialogs to be shared and the provider error was gone.