How to avoid a System.InvalidCastException

[Ed]

I found out about this the hard way, so thought I would share my experience.  Using the RadTreeView version 2009 Q1, I was adding a node to a tree and setting its value on the client-side before committing my changes to the server, like so:

  tree.trackChanges();
  ...
  var childNode = new Telerik.Web.UI.RadTreeNode();
  childNode.set_value(++lastNodeValue);           // lastNodeValue is an *integer*
  parentNode.get_nodes().add(childNode);
  ...
  tree.commitChanges();

on the client, and

  foreach (ClientOperation<RadTreeNode> operation in RadTreeView1.ClientChanges)
  {
    RadTreeNode node = operation.Item;
    string nodeID = node.Value;       // DANGER!
    ...
  }

on the server.  The last line, string nodeID = node.Value, was causing the following error to occur:

System.InvalidCastException: Unable to cast object of type 'System.Int32' to type 'System.String'.

After some investigation, I realised that I needed to cast the node ID to a string in the client-side code in order to avoid an error on the server!  This proved to be successful:

  tree.trackChanges();
  ...
  var childNode = new Telerik.Web.UI.RadTreeNode();
  // cast lastNodeValue to a *string* to avoid a server-side error
  childNode.set_value((++lastNodeValue).toString());
  parentNode.get_nodes().add(childNode);
  ...
  tree.commitChanges();

Maybe in the next release the client-side set_value() function could automatically cast its argument to a string?  Having said that, I don't remember seeing this error in 2008 Q3, so maybe there's a bug somewhere.

Cheers

Ed Graham