Is there any constant value like if we display it in the datagridview it will not display and if we add it in the decimal value the value remains as it is ?

Like what I am doing is, I am making addition of two columns say B,C for the column A like

dataTable.Columns["A"].Expression="B+C";

Now problem is when there is any value of column B or C is null then there is no value in the column A because of A=B+C like 1+null is null.

And even I can not replace 0 where there is null for the column B or C because I am displaying records of each column A,B and C in the datagridview and I don't want to display value for column which has value null so if I replace 0 where there is null then 0 will be displayed for that column which I don't want. So what should I do for that ?

So what is the constant value which I should replace for null value for the column B and C so if value of A remains it is and even that value will not be displayed in the datagridview.