Setting the DataFormatString property of the BoundDataField on the server side.
To access the DataFormatString you can first cast the column as a FormattedGridField. More information can be found here: http://help.infragistics.com/NetAdvantage/ASPNET/2011.1/CLR4.0/?page=Infragistics4.Web.v11.1~Infragistics.Web.UI.GridControls.FormattedGridField_members.html. For a column containing a DateTime type you can set "{0:g}" that will display both the date and time in the record's cell.