The DevExpress ASP.NET Diagram (ASPxDiagram) control allows you to restrict specific edit operations. To prohibit an operation, set the corresponding Allow{Operation} property to false.
In this demo, the RequestEditOperation event handler implements custom logic to determine whether an operation is allowed. The reason event parameter indicates whether the event was raised by user actions or a UI update. If a user tries to execute a prohibited action, an error message is displayed on-screen.