How to check DBNull value in Linq query results

Question

I am using the below code and trying to group by Currency and Code. After this I am trying to loop through the result set.

But the issue is while looping through the

Answer 1

This:

amount = grp.Sum(x => Convert.ToDouble(x["AMOUNT"]))

will not work as you expect. If x["AMOUNT"] is DBNull.Value instead of a valid double, the conversion will fail with an exception. Instead, try:

amount = grp.Sum(x.Field("AMOUNT"))

if you expect that field to be a double. Sum will treat the null values as zero, per MSDN.

Answer 2

I'm not sure which one is getting the error, but you can can compare it to DBNull.Value like so.

String sCurr = obj.currency == DBNull.Value ? "" : obj.currency;

Answer 3

Something like

 amount = grp.Sum(x => Convert.ToDouble(x["AMOUNT"] == DBNull.Value ? 0 : x["AMOUNT"]));

If that is the line that is giving you the problem.

Answer 4

The way to find the number of CELLS with DBNulls for a specific column:

int numOfEmptyColA = MyDataTable.AsEnumerable().Where(p=>p.IsNull("ColA")).Count();