The 'collectionChange' event is not triggered when nodes are ungrouped.

[Mithun]

Hello Syncfusion Team,

Our app uses Syncfusion's DiagramComponent ("@syncfusion/ej2-angular-diagrams": "^17.3.26").

In our app, we'd like to save the user's diagram whenever the user groups or ungroups nodes.

We received the collectionChange event when nodes are grouped together.

However no events are seemingly triggered when the grouped nodes are ungrouped. 

I have a stackblitz demo here (please see the console log there): https://stackblitz.com/edit/diagram-ungroup-no-event

Is this a bug or am I doing something wrong?

Thanks,

Mithun

[Shyam G]

Hi Mithun, 

Please use historyChange event to track the group/ungroup action. Please refer to a code example and modified sample below. 

Code example: 

//inject undo redo module  

Diagram.Inject(UndoRedo) 

<ejs-diagram #diagramControl id="diagram-control" 

      width="100%" height="500px" 

      [contextMenuSettings]="this.contextMenuSettings" 

      (collectionChange)="onCollectionChange($event)" 

      (historyChange)="onHistoryChange($event)"  

      (created)="onCreated()"> 

    </ejs-diagram> 

onHistoryChange(args: IHistoryChangeArgs) {  

    if((args.change as any).type === 'Group' || (args.change as any).type === 'UnGroup') { 

        console.log(`historychange`); 

    } 

  } 

Sample: https://stackblitz.com/edit/diagram-ungroup-no-event-niflhq?file=src/app/app.component.ts 

Help documentation: https://ej2.syncfusion.com/angular/documentation/diagram/undo-redo/?no-cache=1#history-change-event 

Regards, 

Shyam G 

[Mithun]

Thanks Shyam. That worked! 

A small concern though... 

(args.change as any).type === 'Group'

The '.type' property does not seem to be a publicly documented property of  'SelectorModel' (which is the type of args.change).

Just want to future-proof my solution so there are no inadvertent breaking changes in future. 

Thanks,

-Mithun

[Shyam G]

Hi Mithun, 

Sorry for the inconvenience. 

To achieve your requirement, we use interface to implement the type. Please refer to a code example and sample below. 

Code example: 

interface IHistory { 

  type: string 

} 

onHistoryChange(args: IHistoryChangeArgs) {   

    if((args.change as IHistory).type === 'Group' || (args.change as IHistory).type === 'UnGroup') { 

        console.log(`historychange`); 

    } 

  }  

Sample: https://stackblitz.com/edit/diagram-ungroup-no-event-u5mf2g?file=src/app/app.component.ts 

Regards, 

Shyam G