I wonder what mask shall be set to format string during entering.
I have format string set to ###,###,##0
So numbers are displayed correctly when loosing focus from cell
I wonder if I can setup similar input mask allowing user to see thousands separator when he imputs numbers (eg if he is entering 123456, he will see 123,456 still beeing in edit mode)
My current input mask is nnnnnnnnn
Yes, just put the commas in the mask, i.e., set the MaskInput property to "nnn,nnn,nnn". I forget whether we interpret the comma character as a token for the current culture's thousands separator, but if we don't you can get that character from the culture's NumberFormat, and use that instead.