prefferably in design-time, in ASPX code.
HI ,
Try setting the MaxValue property
Here is a help link for that property
http://help.infragistics.com/Help/NetAdvantage/ASPNET/2009.1/CLR3.5/html/Infragistics35.WebUI.WebDataInput.v9.1~Infragistics.WebUI.WebDataInput.WebNumericEdit~MaxValue.html