Make the add button open a custom angular modal

how to make the add button to trigger a custom angular modal. please help me!

Hello Amal,
Do you want to show a custom edit form instead of the default lightbox?
To do that, you need to redefine the gantt.showLightbox or onBeforeLightbox functions:
https://docs.dhtmlx.com/gantt/desktop__custom_edit_form.html

Unfortunately, it is not possible to use Angular elements inside Gantt, you can only return regular HTML elements. But the custom edit form will be displayed separately from Gantt, so it should work.

I don’t have a ready sample with the Angular modal box, but here is a sample with the custom lightbox in angular:
https://files.dhtmlx.com/30d/56cd5bcda63aca2b4616cb86ed8fcff6/angular+custom-lightbox[overlay].zip