Excel "xlWhole is not declared"

I have a sub that is used in several programs  to find the last row in an Excel sheet so I can copy the sheet to an array in VB6. I decided to use this same sub in .Net but it is telling that xlWhole is not declared. What do I declare this as. I thought these statments were imported with the Excel reference.

FirstBlank = mWorkSheet.Columns("A:A").Find(What:="", LookAt:=xlWhole).Row

Err message is "name xlWhole is not declared"

Dan Miel

SolidworksApi macros