Dynamically Expand Link Chart

Lets say you have a Link Chart that the user is interacting with and moving nodes around, etc.
Lets also say that the Link Chart is not fully loaded and has the + sign as a button on some of the nodes that can be expanded further.
So when the user clicks the + button I would like to do an ajax call to retrieve the additional nodes starting from that point and then display on the canvas.

Is something like that possible with out having to reload the whole link chart from the beginning and losing all the positional changes the user had made to the diagram? Are there any examples?

The Incremental Tree sample demonstrates creating nodes and links dynamically when the user clicks on the expand button, including remembering whether that node had ever been expanded in the past.

Instead of adding the node and link data immediately, you can do so when you get the AJAX results. You could even show some kind of error decoration on the node if the request fails. In fact, you might want to show a “querying…” decoration on the node during while waiting for the results. That way the user could try expanding several nodes before the results come back for any of them.