InjectionToken mat-dialog-scroll-strategy

Introduction

mat-dialog-scroll-strategy is an InjectionToken provided by Angular Material that allows you to control the scrolling behavior in dialog components. It serves as a configuration option for the scroll strategy used by the Angular Material dialog service.

Scroll Strategy

Angular Material provides various scroll strategies out of the box to handle dialog scrolling. By default, the mat-dialog-scroll-strategy is set to reposition, which keeps the original scrolling behavior and adjusts the dialog position on the screen if it goes off-screen during scrolling.

Usage

To customize the scroll strategy for the dialog, you need to provide an InjectionToken value of type ScrollStrategy using the MAT_DIALOG_SCROLL_STRATEGY token. Here's an example of how to provide a custom scroll strategy:

import { MAT_DIALOG_SCROLL_STRATEGY, ScrollStrategy } from '@angular/material/dialog';
import { Overlay } from '@angular/cdk/overlay';

export function customDialogScrollStrategy(overlay: Overlay): () => ScrollStrategy {
  return () => overlay.scrollStrategies.reposition();
}

@NgModule({
  providers: [
    {
      provide: MAT_DIALOG_SCROLL_STRATEGY,
      useFactory: customDialogScrollStrategy,
      deps: [Overlay]
    }
  ]
})
export class AppModule { }

In the above example, we have created a custom scroll strategy customDialogScrollStrategy that uses the reposition strategy provided by the Overlay service. We then provide it as a factory function for the MAT_DIALOG_SCROLL_STRATEGY token in the providers array of your module. This ensures that the custom scroll strategy is used by Angular Material dialogs.

Conclusion

Using the InjectionToken mat-dialog-scroll-strategy provided by Angular Material, you can easily customize the scroll strategy for dialog components. By providing a custom scroll strategy, you can control how the dialog behaves during scrolling, enhancing the user experience and meeting specific requirements.