Doh! That works. I don't understand why, but it does. Thanks Alexandre.

>Sorry Roi if you if you do vartype you will get an error but if you do TYPE has I said then if the SelectKey is invalid type will return U so try the following:
>

>IF TYPE('This.Nodes[SelectedKey]') = 'O'
>   This.SelectedItem = This.Nodes[SelectedKey]
>ENDIF
>

>
>>Nope, This.Nodes is a method that returns an object. The SelectedKey is just a string for the index key. If the index key references a non existant node an error occurs. That's my problem. I need to know if the object exists in the collection prior to calling This.Nodes.
>>
>>>Roi and how about TYPE('This.Nodes[SelectedKey]') This should work.
>>>
>>>>Same deal, This.Nodes[SelectedKey] causes and error. I think I just have to catch the error and go from there.
>>>>
>>>>>Sorry try this one:
>>>>>>I have a method that rebuilds all the nodes in a treeview.
>>>>>>
>>>>>>I save the currently selected node with:
>>>>>>

SelectedKey = This.SelectedItem.Key

>>>>>>
>>>>>>Then I clear all the nodes and rebuild the tree.
>>>>>>
>>>>>>Then I want to reselect the Selected item with:
>>>>>>

This.SelectedItem = This.Nodes[SelectedKey]
>>>>>>This.SelectedItem.ensurevisible

>>>>>>
>>>>>>However sometimes the SelectedKey doesn't exist once the tree is rebuilt. Is there an easy way to determine that? I can't spin through all the keys because I build each branch dynamically as it is expanded. The only thing I've can think of is setting it, catching the error if it doesn't exist, and going on from there.
>>>>>>
>>>>>>tia