Thank you for your question.
The ThousandsSeparator property determines the behavior of the default editor that GridViewDecimalColumn displays. However, this property has no effect on the text of the cells. If you need to format the text of the cells, you can use the FormatString property:
.radGridView1.Columns(0), GridViewDecimalColumn).FormatString =
I hope this helps.
the Telerik team
Q1’11 SP1 of RadControls for WinForms is available for download
; also available is the Q2'11 Roadmap
for Telerik Windows Forms controls.