问没有提供MdDialog错误的提供者

EN

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

import { Aircraft } from '../shared/aircraft';
import { AircraftService } from '../shared/aircraft.service';
import { MdDialog, MdDialogRef } from '@angular/material';
import { NewAircraftDialogComponent } from '../new-aircraft-dialog/new-aircraft-dialog.component';

@Component({
  selector: 'app-statusboard',
  templateUrl: './statusboard.component.html',
  styleUrls: ['./statusboard.component.css']
})
export class StatusboardComponent implements OnInit {
  aircrafts: Aircraft[] = [];

  constructor(private aircraftService: AircraftService,
              public dialog: MdDialog) { }

  ngOnInit(): void {
    this.aircraftService.getAircrafts()
      .then(aircrafts => this.aircrafts = aircrafts);
  }

  openNewAircraftDialog(): void {
    let dialogRef = this.dialog.open(NewAircraftDialogComponent, {
      width: '300px'
    });

    dialogRef.afterClosed().subscribe(result => {
      console.log('The dialog was closed');
    });
  }
}

import { Component, OnInit } from '@angular/core';
import { Aircraft } from '../shared/aircraft';
import { AircraftService } from '../shared/aircraft.service';
import { MdDialogRef } from '@angular/material';

@Component({
  selector: 'app-new-aircraft-dialog',
  templateUrl: './new-aircraft-dialog.component.html',
  styleUrls: ['./new-aircraft-dialog.component.css']
})
export class NewAircraftDialogComponent implements OnInit {

  newAircraft: Aircraft;

  constructor(private aircraftService: AircraftService,
              public dialogRef: MdDialogRef<NewAircraftDialogComponent>) { }

  ngOnInit() {
  }

  onSubmitClick(): void {
    this.dialogRef.close();
  }

  onCloseClick(): void {
    this.dialogRef.close();
  }

}