Be taught Angular 11 MatDialog Fundamentals

Of all of the Angular Materials elements, the MatDialog simply will be the most advanced. On the similar time, it’s most likely additionally essentially the most versatile of the bunch. A part of the reason being that it’s not a part a lot as a service that may be utilized to open modal dialogs with Materials Design styling and animations. On this tutorial, we’ll substitute the usual JavaScript affirm dialog that we carried out within the Stopping Knowledge Loss In Angular Functions utilizing a CanDeactivate Route Guard tutorial with a MatDialog:

JavaScript Verify Dialog

Angular Verify Dialog

Including MatDialog to the Materials Module File

Recall that we positioned all of our Angular Materials imports within the srcappsharedmodulesmaterialmaterial.module.ts file. We are going to now add MatDialog to the listing:

import {MatDialogModule} from '@angular/materials/dialog';

const materialModules = [
  //...
  MatToolbarModule,
  MatDialogModule
];

Creating the ConfirmDialog Element

A part of what makes MatDialog so versatile is that its open() methodology accepts a part to point out within the physique of the dialog. You could be tempted to create the part as a baby to the one that may name it, however it could be clever to assume twice earlier than doing in order we might wish to reuse the identical dialog in different places inside out utility sooner or later. For that motive, I’d advocate producing it throughout the app listing:

ng g c confirm-dialog

Within the confirm-dialog.part.ts file, we are going to modify the constructor to just accept a reference to the dialog in addition to the info that we’ll go to it:

import { Element, Inject, ViewEncapsulation } from '@angular/core';
import { MatDialogRef, MAT_DIALOG_DATA } from '@angular/materials/dialog';

@Element({
  selector: 'app-confirm-dialog',
  templateUrl: './confirm-dialog.part.html',
  styleUrls: ['./confirm-dialog.component.css'],
  // this can enable us to override the mat-dialog-container CSS class
  encapsulation: ViewEncapsulation.None
})
export class ConfirmDialogComponent {

  constructor(
    public dialogRef: MatDialogRef<ConfirmDialogComponent>,
    @Inject(MAT_DIALOG_DATA) public knowledge: any) 
  { }
}

Subsequent, we’ll add the contents of the dialog to the confirm-dialog.part.html file:

<div class="dialog-header accent-background">
  <span class="dialog-header-title">{{knowledge.dialogTitle}}</span>
</div>
<div class="dialog-content">
  <p>{{knowledge.dialogMessageLine1}}<br/>
  {{knowledge.dialogMessageLine2}}</p>
</div>
<div class="dialog-footer">
  <button class="standard-button dialog-button" mat-raised-button [mat-dialog-close]="false" cdkFocusInitial>{{knowledge.noButtonText}}</button>
    
  <button mat-raised-button coloration="major" [mat-dialog-close]="true">{{knowledge.yesButtonText}}</button>
</div>

Invoking the MatDialog Service

Again within the survey.part.ts file, we’re able to replace the canExit() methodology to current our customized dialog as an alternative of the native JavaScript affirm dialog. There are three issues we have to do to make that occur:

1. Add a constructor that accepts a MatDialog reference.
2. Add the openUnsavedChangesDialog() methodology. It’s liable for displaying the dialog.
3. Invoke the openUnsavedChangesDialog() methodology from canExit().

Right here is the up to date supply code for the survey.part.ts file that reveals the related modifications:

// imports
import { MatDialog } from "@angular/materials/dialog";
import { ConfirmDialogComponent } from "../confirm-dialog/confirm-dialog.part";

// SatisfactionRatings enum

@Element({
  selector: "app-survey",
  templateUrl: "./survey.part.html",
  styleUrls: ["./survey.component.css"]
})
export class SurveyComponent implements IDeactivateComponent {
  // declarations

  constructor(public dialog: MatDialog) { }

  //strategies...

  public canExit(): boolean | Observable<boolean> {
    return this.ngFormRef.soiled
      ? this.openUnsavedChangesDialog()
      : true;
  };

  non-public openUnsavedChangesDialog(): Observable<boolean> {
    const dialogRef = this.dialog.open(ConfirmDialogComponent, {
      width: '26.5rem',
      knowledge: { 
        dialogTitle: 'Unsaved Modifications', 
        dialogMessageLine1: 'You may have unsaved modifications.',
        dialogMessageLine2: 'Are you certain you need to depart the web page?',
        yesButtonText: 'Go away this Web page',
        noButtonText: 'Keep on this Web page'
      }
    });

    return dialogRef.afterClosed();
  }
}

The openUnsavedChangesDialog() Technique Defined

There’s rather a lot happening on this little methodology, so let’s unpack it.

The dialog reference that we injected through the constructor gives quite a few strategies, properties, and occasion hooks for working with it, a very powerful of which being the open() methodology. It accepts the part to show in addition to a MatDialogConfig object. That’s the place we set the dialog’s look and go alongside the info object that populates the dialog part.

The afterClosed() occasion hook receives an observable that’s notified when the dialog is completed closing. We will do no matter processing we have to do after the dialog is closed. In our case, we don’t have to do something however go alongside the worth returned by the dialog. That will get set by the 2 buttons within the footer through the sure [mat-dialog-close] attribute:

<div class="dialog-footer">
  <button class="standard-button dialog-button" mat-raised-button [mat-dialog-close]="false" cdkFocusInitial>{{knowledge.noButtonText}}</button>
  &nbsp;&nbsp;
  <button mat-raised-button coloration="major" [mat-dialog-close]="true">{{knowledge.yesButtonText}}</button>
</div>

We then want so as to add the Observable<boolean> return sort to canExit() to accommodate the afterClosed() return worth.

Right here’s the top results of at this time’s updates to the Stopping Knowledge Loss In Angular Functions utilizing a CanDeactivate Route Guard demo. To check it, navigate to the Survey web page, work together with the shape in order to replace the underlying mannequin, after which click on the Residence hyperlink:

Conclusion

On this tutorial, we realized use the MatDialog, essentially the most advanced, and but most versatile Angular Materials part. To try this, we changed the usual JavaScript affirm dialog that we carried out within the Stopping Knowledge Loss In Angular Functions utilizing a CanDeactivate Route Guard demo with a MatDialog.