I seem to have resolved the first issue by applying a template to each node on the NodeBound event. However, I now have a new issue. After a postback, every node loses the previously bound DataItem.

Keeping in mind that I'm binding the data programmatically (as these are IEnumerable's and not datasets as all the examples seem to use), how can I ensure that all the nodes in the tree persist their DataItems after a postback, or alternatively, how can I create a binding source in the ASPX page that creates the children from an IEnumerable property in the parent?

Thanks,

Alex

• Node Editing
• Data Binding Sample

https://msdn.microsoft.com/en-us/library/ms178472(v=vs.100).aspx

https://msdn.microsoft.com/en-us/library/aa719775(v=vs.71).aspx

Which means the objects have been disposed (controls and data included). While the ASPX markup will re-initialize the WebDataTree control on the Page once postback occurs, if you assign data source in code, it will need to be assigned again.  I think you will agree with me that transferring all data back and forth via viewstate is an extreme measure as well. However, note that if you use async postbacks the page and controls will not be rendered (as that is the whole point of ajax) and re-binding should only happen if it is required which is left entirely to the developer to decide.

The event arguments carry information for the selected node that is always available, while tree collections and related (active item) will require databind:

protected void WebDataTree1_NodeClick(object sender, DataTreeNodeClickEventArgs e)

{

    //Always present properties:

    string value = e.Node.Value;

    string text = e.Node.Text;

    int level = e.Node.Level;

    int index = e.Node.Index;

    // Requires data binding:

    object item = (sender as WebDataTree).ActiveNode.DataItem;

}

So the choice is really up to you – if the info in the node is not enough to decide your application's reaction and you need access to the data items then you can freely query your data without binding the tree.

If the data retrieval is the bottleneck, then it should probably be cached on the server side as that is the entire point of data binding – controls are data-bound not data-containing/caching.

I hope that is helpful and do let me know if you if there's anything else we can help with on this matter.

Regards,

Damyan Petev

Associate Software Developer

Infragistics, Inc.