Hello,

I used XamGrid and created some custom inheriting ColumnContentProviderBase and TemplateColumn as wanted and all seem to work just fine - I have in-edit-mode custom cell editors and display-mode editors etc....

Now, I have also created a custom dropdown control (a lookless control) and used it in the datagrid as a cell editor, but now when I selet an item from the my dropdown (in edit mode) and this element is databound (SelectedValue - two way, explicit mode, no binding errors in output), when I leave the cell, I get the following exception: Operation is not valid due to the current state of the object with the following stack trace:
en System.Windows.Data.BindingExpression.UpdateSource()
   en Infragistics.Controls.Grids.CellControl.EvaluateEditingBindings()
   en Infragistics.Controls.Grids.XamGrid.ExitCellFromEditModeInternalRow(Boolean cancel)
   en Infragistics.Controls.Grids.XamGrid.ExitEditModeInternal(Boolean cancel)
   en Infragistics.Controls.Grids.XamGrid.SetActiveCell(CellBase cell, CellAlignment alignment, InvokeAction action, Boolean allowSelection, Boolean setFocus, Boolean scrollIntoView)
   en Infragistics.Controls.Grids.XamGrid.SetActiveCell(CellBase cell, CellAlignment alignment, InvokeAction action, Boolean allowSelection, Boolean scrollIntoView)
   en Infragistics.Controls.Grids.XamGrid.SetActiveCell(CellBase cell, CellAlignment alignment, InvokeAction action, Boolean allowSelection)
   en Infragistics.Controls.Grids.Cell.OnCellMouseDown(MouseEventArgs e)
   en Infragistics.Controls.Grids.XamGrid.XamWebGrid_MouseLeftButtonDown(Object sender, MouseButtonEventArgs e)
   en MS.Internal.CoreInvokeHandler.InvokeEventHandler(Int32 typeIndex, Delegate handlerDelegate, Object sender, Object args)
   en MS.Internal.JoltHelper.FireEvent(IntPtr unmanagedObj, IntPtr unmanagedObjArgs, Int32 argsTypeIndex, String eventName)

If I remove the my SelectedValue  binding, I can leave the current edit mode cell without any errors. I believe I am doing something wrong in my custom-dropdown somewhere, but if I use my control outside the datagrid, I don't get any exeptions when the focus moves away from it and the selection binding works fine.

What might be the problem when using my custom control in the datagrid? Any tip is appreciated. Thanks