The Telerik ASP.NET Diagram control is based on the Telerik HTML5 Diagram widget, part of
Kendo UI. In order to save and load data in JSON format with RadDiagram for ASP.NET AJAX, you need to reference the Kendo UI Diagram and call its save() and load() functions or create it from JSON data.
var
diagram = $find(
"<%= brackets.ClientID %>"
).get_kendoWidget();
var
json = diagram.save();
//the diagram shapes and connections are saved in the JSON variable
//or
diagram.load(
/* JSON code */
);
//load the JSON in the diagram
This ASP.NET Diagramming demo shows a possible implementation of the save/load functionality. By clicking on Download you will start a download of a .json file that contains the data of the diagram. If you click Upload you can select a .json file with data that will be used for generating a new diagram.
The set of buttons Serialize to JSON and Load from JSON provide the same functionality, however in this case you can copy and paste the data directly from the textarea that is positioned between the buttons.