UltraTree's OutlookExpress ViewStyle is designed to present recursive relations such as 'PartCategoryTable.PartCategoryID to PartCategoryTable.PartCategoryParentID'. I am not able to visualize, however, how you would present the two relations as Windows Explorer does, since Explorer presents the folders in a tree (for this you would use the Standard ViewStyle) and files in a ListView. I'm not sure if this helps, but the UltraListView 'Infragistics FileExplorer' sample that ships with the SDK demonstrates how to do this, although it uses the local machine's file system as data, and does not utilize data binding.

I found a forum posting that is IDENTICAL to what I want, but the answer seems to stop just shy of enough information.
http://forums.infragistics.com/forums/p/13130/48568.aspx

I've gotten the relationships set up the way I want.  I hide all the nodes except for the true root-most node.  Now, when I expand my first node ("COMPONENTS"), it shows the names of the relationships ("IPart4" and "PARTCATEGORY_PARTCATEGORY").  This is where I thought the above post would come in handy.  Can someone expand upon Mike's info?

But, to top it ALL off, I seem to get a few odd behaviors that is making my life quite frustrating:
1. Sometimes, when I start the application, it seems as though the Tree doesn't load the data.  It comes up blank.  To resolve this, I just restart my little test app.
2. Sometimes there is a long delay when expanding the nodes.  Othertimes, it's really fast.
3. When I have the following code in the InitializeDataNode event, it throws an exception.  If I comment out the e.Node.Visible = False line, it doesn't throw the exception.
Select Case e.Node.Level
Case 0
  If e.Node.Cells("PartCategoryParentID").Text.Trim() <> "0" Then
    e.Node.Visible = False
  End If
Case Else
  If e.Node.Nodes.Count = 0 Then
    e.Node.Visible = False
  End If
End Select
4. Even if I comment out the e.Node.Visible = False line, but place a breakpoint, using F5 to continue, it will throw an exception.

Is the 9.1.2023 UltraWinTree buggy?

Full Stack Trace:
System.ArgumentException: Item has already been added. Key in dictionary: 'PARTCATEGORY_PARTCATEGORY'  Key being added: 'PARTCATEGORY_PARTCATEGORY'
   at System.Collections.Hashtable.Insert(Object key, Object nvalue, Boolean add)
   at System.Collections.Hashtable.Add(Object key, Object value)
   at Infragistics.Win.UltraWinTree.NodeClientAreaUIElement.CacheNodeElements(Hashtable table, UIElementsCollection oldElements, Int32 startIndex)
   at Infragistics.Win.UltraWinTree.NodeClientAreaUIElement.PositionChildElements()
   at Infragistics.Win.UIElement.VerifyChildElements(ControlUIElementBase controlElement, Boolean recursive)
   at Infragistics.Win.UIElement.VerifyChildElements(Boolean recursive)
   at Infragistics.Win.UIElement.VerifyChildElements()
   at Infragistics.Win.UltraWinTree.UltraTreeUIElement.PositionChildElements()
   at Infragistics.Win.UIElement.VerifyChildElements(ControlUIElementBase controlElement, Boolean recursive)
   at Infragistics.Win.UIElement.VerifyChildElements(Boolean recursive)
   at Infragistics.Win.UIElement.VerifyChildElements()
   at Infragistics.Win.UltraWinTree.UltraTreeNode.BringIntoViewHelper(Boolean includeChildNodes, Boolean includeHorizontal, Boolean includeVertical, Boolean leftOnly)
   at Infragistics.Win.UltraWinTree.UltraTreeNode.BringIntoViewHelper(Boolean includeChildNodes, Boolean includeHorizontal)
   at Infragistics.Win.UltraWinTree.UltraTree.SetActiveNode(UltraTreeNode node, Boolean bringIntoView, Boolean adjustHorizontalPosition)
   at Infragistics.Win.UltraWinTree.UltraTree.set_ActiveNode(UltraTreeNode value)
   at Infragistics.Win.UltraWinTree.UltraTreeNode.internalExpand(Boolean value, Boolean notify, Boolean updateVisibleNodes)
   at Infragistics.Win.UltraWinTree.UltraTreeNode.set_Expanded(Boolean value)
   at Infragistics.Win.UltraWinTree.UltraTreeNode.Toggle()
   at Infragistics.Win.UltraWinTree.ExpansionIndicatorUIElement.Toggle()
   at Infragistics.Win.ExpansionIndicatorUIElement.OnMouseDown(MouseEventArgs e, Boolean adjustableArea, UIElement& captureMouseForElement)
   at Infragistics.Win.ControlUIElementBase.ProcessMouseDownHelper(Object sender, MouseEventArgs e)
   at Infragistics.Win.ControlUIElementBase.ProcessMouseDown(Object sender, MouseEventArgs e)
   at Infragistics.Win.Utilities.ProcessEvent(Control control, ProcessEvent eventToProcess, EventArgs e)
   at Infragistics.Win.UltraControlBase.OnMouseDown(MouseEventArgs e)
   at Infragistics.Win.UltraWinTree.UltraTree.OnMouseDown(MouseEventArgs e)
   at System.Windows.Forms.Control.WmMouseDown(Message& m, MouseButtons button, Int32 clicks)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)