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How to make NgbModal draggable with @angular/cdk

I have some difficulties with figuring out how to make my modals draggable. I have reusable modals with its own service which is called to create one inside components.

confirm.modal.service.ts

import { Injectable } from "@angular/core";
import { NgbModal } from "@ng-bootstrap/ng-bootstrap";
import { Observable, from, EMPTY, throwError } from "rxjs";
import { catchError, tap } from "rxjs/operators";

import { ConfirmModalComponent } from "./confirm-modal.component";

export interface ConfirmOptions {
    title: string;
    subtitle?: string;
    errorOnClose?: boolean;
}

@Injectable({ providedIn: "root" })
export class ConfirmModalService {
    constructor(private modalService: NgbModal) {}

    confirm(options: ConfirmOptions): Observable<boolean> {
        const modalRef = this.modalService.open(ConfirmModalComponent, {
            centered: true
        });
        modalRef.componentInstance.title = options.title || "Are you sure?";
        modalRef.componentInstance.subtitle = options.subtitle || null;

        return from(modalRef.result).pipe(
            tap(),
            catchError(err =>
                options.errorOnClose
                    ? throwError(err || "not confirmed")
                    : EMPTY
            )
        );
    }
}

confirm.modal.module.ts

import { NgModule } from "@angular/core";
import { CommonModule } from "@angular/common";
import { DragDropModule } from "@angular/cdk/drag-drop";

import { ConfirmModalComponent } from "./confirm-modal.component";

@NgModule({
    imports: [
        CommonModule,
        DragDropModule
    ],
    declarations: [ConfirmModalComponent],
    exports: [ConfirmModalComponent]
})
export class ConfirmModalModule {}

confirm.modal.component.ts

import { Component, Input } from "@angular/core";
import { NgbActiveModal } from "@ng-bootstrap/ng-bootstrap";

@Component({
    selector: "app-confirm-modal",
    templateUrl: "./confirm-modal.component.html",
    styleUrls: ["./confirm-modal.component.scss"]
})
export class ConfirmModalComponent {
    @Input() title: string;
    @Input() subtitle: string;

    constructor(public activeModal: NgbActiveModal) {}

    public accept(): void {
        this.activeModal.close(true);
    }

    public dismiss(): void {
        this.activeModal.close(false);
    }
}

confirm.modal.component.html

<div class="modal-body">
    <div class="modal-body__header">
        <span>{{ title }}</span>
    </div>
    <div *ngIf="subtitle" class="modal-body__text">
        <span>{{ subtitle }}</span>
    </div>
    <div class="modal-body__button-row">
        <button class="btn btn-primary" (click)="accept()">Yes</button>
        <button class="btn btn-light" (click)="dismiss()">Cancel</button>
    </div>
</div>

So I want to make the whole modal be draggable with Angular built-in DragDropModule, hence I should add cdkDrag inside element with class='modal-content' but I don’t how to achieve that with current setup. NgbModalOptions provides functionality to add class only but not attribute directive. I know that there is easier solution with JQuery draggable, but I would like to avoid that.

I was thinking about using @ViewChildren for each page but it doesn’t seem to the best solution for me.

Thanks for any help!

Answer

Just wrap your modal inside a container and add the cdkDragRootElement to it as per the documentation. You will also have to add this class as an option when you open the dialog from the component.ts.

<ng-template #content
  let-modal>
    <div
      cdkDrag
      cdkDragRootElement=".your-custom-dialog-class">
      <div class="modal-header">
    
      </div>
      <div class="modal-body">
    
      </div>
    
      <div class="modal-footer">
      </div>
    </div>
</ng-template>

The code for the component.ts

const options: NgbModalOptions = {
windowClass: 'your-custom-dialog-class'
};
this.modalService.open(this.content, options);