public void RaiseTemplatesChanged( 
   string propertyname
)

Parameters

propertyname

the name of the modified dictionary property

You should call this after dynamically modifying the contents of one of the following dictionaries: NodeTemplateDictionary, GroupTemplateDictionary, or LinkTemplateDictionary. Pass the name of one of those three properties as the argument.

This method is called automatically when you set any of the Diagram properties that are of type DataTemplate or DataTemplateDictionary.

Reference

Diagram Class
Diagram Members