Hi Lan,
Sorry for the inconvenience caused. Currently we have no special property to set the diagram as read only. However, I have logged this as a feature request 1351. You can track the status of this feature here:
Feature Request 1351 -Add ReadOnly property for the diagram control.We will try our very best to implement this feature at the earliest. Diagram user interactivity is enabled through the interactive Tools registered with the Diagram's Controller. We updated to set the diagram readonly at
http://www.syncfusion.com/support/forums/message.aspx?&MessageID=26450
Please kindly refer to this forum link. I have also attached the sample that demonstrates this completely. Please refer to this sample and let me know if you have any questions.
Thanks for using syncfusion product.
Regards,
Nagaraj
ReadOnlyDiagram.zip