Basically, in a Treeview if you have something databound to your object, and the binding statement path uses Path=My Property.Subproperty, the async binding statement for all the nodes displayed under a parent node take the sum time of all async calls to resolve before any UI is updated, but it does not block the UI, everything still moves smoothly.Because of this huge amount of data, I decided to used asynchronous calls.In page load I add to treeview only root of the tree, on selected treeviewitem I ask asynchronous server for his nodes.

This exception may also indicate an attempt to call an "async void" method, which is generally unsupported within ASP. Instead, the asynchronous method should return a Task, and the caller should await it.

Is it possible to bind treeview asynchronously using this method, or not?

Because of huge amount of data I do not want to ask server for all data and display them in treeview.

The problem I'm having is that the Tree View flickers everytime this occurs. Each feed is represented in the Tree View by its own node and this node is updated in the callback.

I tried doing Suspend Layout before the update and Resume Layout afterwards but it doesn't seem to have any effect. I tried calling Begin Update before updating the associated node and then End Update after the update was done but am still getting flickering.