Not allow the removal of certain nodes

Question

Hi, I am looking into how to forbid the user on deleting certain nodes from the diagram.

I've tried setting theargs.cancelproperty to true in the collectionChange event but the node keeps getting deleted from the diagram.

I don't know where I should place the condition in order to let the user know that she can't delete the tried node.

Balasubramanian Manikandan · Accepted Answer

In collectionChange event, you should set args.cancel
to true when the state “Changing” to prevent deleting of nodes. Refer to
the below mentioned code example and sample.

Code Example:
  function collectionChange(args) {
    if (
      args.state == 'Changing' &&
      args.type == 'Removal' &&
      args.element.id == 'support'
    ) {
      args.cancel = true;
    }
  }

Sample:
  https://stackblitz.com/edit/tgqqv6-bf1dnw?file=index.html,index.js