What do you mean by processing blank values?
You want to remove the blank rows or write some data because as of now i do not see anything that you are doing for blank check
And also currentrow = Nothing is wrong syntax…and if you want to check if any of the column in current row is blank then currentrow.itemarray.contains(string.empty) is more appropriate
And the comparison of currentrow.tostring= row.tostring will also be always true because both return system.data.datarow …here as well you are not comparing the values ypu are comparing the type of those rows
If you can share a sample input and smaple output that would be help because as of now i see what you are trying and what you wrote are two different things and of which , what you want to do is also not very clear to advice on what to do next
Cheers
Cheers