Add annotation to the diagram objects while dragging it from palette onto the diagram

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You can dynamically add an annotation to a node when dragging a node from the palette and dropping it onto the diagram using the drop event. In the following article, we will explain how to achieve this by incorporating a dialog control.

Adding annotation content to the node with a dialog box

In the provided sample, when a node is dragged from the palette and dropped onto the diagram, the drop event is triggered. In this event, a dialog box is opened. Below is the corresponding code example for reference.

<ejs-diagram #diagram id="diagram" width="100%" height="100%"

(drop)="drop($event)" >

</ejs-diagram>

//drop event

public drop(args: IDropEventArgs): void {

let obj = args.element;

if (obj instanceof Node || obj instanceof Connector){

//get an selecteditem id

this.objectFromPalette = obj.id;

}

this.promptDialog.show();

//open a dialog box

this.dialogOpen();

}

In the dialog box, you can enter text, which will be appended to the node or connector upon pressing the submit button. Closing the dialog or pressing the cancel button will remove the selected diagram element. Below is the corresponding code example.

App.component.html

<ejs-dialog #promptDialog [buttons]='promptDlgButtons' [visible]='hidden' [header]='promptHeader' [animationSettings]='animationSettings' [showCloseIcon]='showCloseIcon' [target]='target' (open)="dialogOpen()" (close)="dialogClose()" [width]='promptWidth' >

<ng-template #content>

<tr>

<td>Annotation Content:</td>

</span></td>

</tr>

</table>

</ng-template>

</ejs-dialog>

</diV>

App.component.ts

// bind the values entered in the textbox to the node

public promptDlgButtons: ButtonPropsModel[] = [

{ click: this.objectPropertiesChange.bind(this), buttonModel: { content: 'Submit', isPrimary: true } },

{ click: this.closeDialogButton.bind(this), buttonModel: { content: 'Cancel' } }];

// method to append a annotation to the node

public objectPropertiesChange() {

if (this.objectFromPalette !== '') {

let obj = this.diagram.getObject(this.objectFromPalette);

let content = (document.getElementById('annotationContent') as HTMLInputElement).value;

if ((obj instanceof Node || obj instanceof Connector) && obj.annotations.length > 0) {

if (content == '') {

this.diagram.remove(obj);

} else{

obj.annotations[0].content = content;

this.diagram.dataBind();

}

this.promptDialog.hide();

}

//method to remove the object while closing the dialog

public closeDialogButton() {

if (this.objectFromPalette !== '') {

let obj = this.diagram.getObject(this.objectFromPalette);

//remove the diagram element

this.diagram.remove(obj);

}

this.promptDialog.hide();

}

Please find the sample here for your reference.

Sample:

https://stackblitz.com/edit/angular-c6dmfq-bbz5sh?file=app.component.ts

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Add annotation to the diagram objects while dragging it from palette onto the diagram

Adding annotation content to the node with a dialog box

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