Get rid of   value in gridview cells value

For gridview, let's say I have a empty space for 1 column in a datarow

I used 
row.Cells[2].Text.Trim() to retrieve the data
but I get   
Is there any other way to prevent this whitespace, as if the column is null, I want it to display error message.

Perhaps I should Update Set Col='NULL' instead of Col=''

...