>>I don't think VFP code can easily be ported into C#, it's quite complex and uses macro substitution.
>
>Then make samples of input and output of different data types and values
>
>The usual much ado about nothing

I posted the sample several times in this thread. That was sample of input. The output is simple: if I have empty string in the field as input and 0 in numerical column value, they should compare equal.

Rob's solution was perfect and this piece of logic now works great. Unfortunately, a little farther in the logic I still get the famous Invalid cast exception. I started to look at it last night, hope to go to the bottom today.