The following article will show how you can save the RadDiagram in IsolatedStorage and load it.
Let's first configure our XAML. We'll keep it simple - two buttons for Save and Load and a Diagram with one shape.
In code behind we are using the Click event handlers of our Save/Load Buttons. On Save, we get an IsolatedStorage and create a folder and a file in it.
Then we use the RadDiagram.Save() - this returns a string with the serialized Diagram. Having this string, the final step is to use StreamWriter to write the string into the file from the storage.
On Load, we open the created file from storage and use StreamReader and RadDiagram.Load() method.