You should set the DisplayMember
properties of RadMultiColumnCombpBox
to the same numeric property - in this case the 'codigoFactura'
I hope this helps. If you have any questions, do not hesitate to write me back.
the Telerik team
Q3’10 SP1 of RadControls for WinForms is available for download
; also available is the Q1'11 Roadmap
for Telerik Windows Forms controls.