Once you find which item is causing the problem, you can put in a check. I use a function such as NumNull(exp(i)) or StrNull(item_name(i) . Here are the functions: Function NumNull(Number As Object) As Object If Number IsNot DBNull.Value Then NumNull = Number Else NumNull = 0 End If End Function Function StrNull(Str As Object) As Object If Str IsNot DBNull.Value Then StrNull = Str Else StrNull = "" End If End Function

I just use comboboxname.text. It will be a text file. If you want to get something from the DB, forget the index and just use a sql statement "SELECT * FROM db WHERE value = '" & comboboxname.text & "'"

Have you tried For i as integer = 0 to R1200s.Rows.Count-1 Next i