Hi Nadeem,
With regards to save the diagram to memory stream, this can be achieved by using the Save method of the DiagramControl. We have created a simple sample to represent this. please refer to the sample from the attachment.
Note: While loading from memory stream please make sure the stream’s Position property is set to 0.
For further details about the Export and Import using Streams, please refer to the following online help documentation.
link:
http://help.syncfusion.com/ug_94/User%20Interface/WPF/Diagram/index.htm and Navigate to the concepts and features.-> Diagram View-> Export diagram in image format
Please let us know if you have any concerns.
Regards,
Ramya
DiagramviewExport_baf1a268.zip