Angular + Material - How to refresh a data source (mat-table)

📝 Angular + Material - How to refresh a data source (mat-table) 🔄

Are you having trouble refreshing the data source in your Angular application when using the Material mat-table component? You're not alone! Many developers face this issue when implementing dynamic data updates. But worry not, because I'm here to guide you through the process. Let's dive in!

🔍 The Problem: Refreshing the Data Source

In the given context, the objective is to refresh the data source (mat-table) after adding a new language using a dialog panel. However, despite calling the refresh method and reinitializing the data source, no changes are applied.

💡 The Solution: The Correct Method

To resolve this issue, there are a few steps we need to follow. Let's take a closer look at the code and make necessary adjustments.

1️⃣ In LanguageDataSource class:

• Import the BehaviorSubject from RxJS using import { BehaviorSubject } from 'rxjs';.

• Create a private BehaviorSubject variable, let's name it dataSubject, and initialize it with an empty array. This will act as our data source.

• Replace the connect() method with the following code:

  connect(): Observable<any[]> { return this.dataSubject.asObservable(); }

• In your refresh() method, after receiving the updated data from the backend, update the dataSubject with the new data:

  refresh() { this.authService.getAuthenticatedUser().subscribe((res) => { this.user = res; this.dataSubject.next(this.user.profile.languages.teach); }); }

2️⃣ In LanguageComponent class:

• Remove the teachDS property and the LanguageDataSource import. We will make use of the MatTableDataSource provided by Angular Material instead.

• Import the MatTableDataSource from Angular Material using import { MatTableDataSource } from '@angular/material';.

• Replace the refresh() method code with the following:

  refresh() { this.authService.getAuthenticatedUser().subscribe((res) => { this.user = res; this.teachDS = new MatTableDataSource(this.user.profile.languages.teach); }); }

• In the template, bind the mat-table to the teachDS property:

  <table mat-table [dataSource]="teachDS"> <!-- column definitions --> </table>

3️⃣ Lastly, don't forget to call the refresh() method after the add language dialog is closed:

add() {
  this.dialog.open(LanguageAddComponent, {
    data: { user: this.user },
  }).afterClosed().subscribe(result => {
    this.refresh();
  });
}

🎉 You Did It!

Congrats! You've successfully implemented the necessary changes to refresh the data source (mat-table) when adding a new language. Now, when the user adds a new language using the dialog panel and returns back, the changes will be reflected in the table.

👉 Engage with us

Have you encountered other challenges while working with Angular + Material? Let us know in the comments below! We're here to help you solve your coding mysteries.

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Thanks for reading! Happy coding! 💻✨