InvalidCastException in a LINQ query

Question

For this LINQ query I'm getting the exception below:

(from row in ds.Tables[0].AsEnumerable()
 where row.Field<string>("Dept_line_code") == DeptCode &&
 row.Field<string>("Skill_Name") == skill &&
 row.Field<string>("Acct_Code") == account && row.Field<string>("Location") == dtNewTable.Rows[intRow]["Location"].ToString()
 select row.Field<int>("Presently_Available") == null ? 0 : row.Field<int>("Presently_Available")
).FirstOrDefault();

Exception information:

Exception type: InvalidCastException

Exception message: Cannot cast DBNull.Value to type 'System.Int32'. Please use a nullable type.

I don't know nullable type and I'm not getting how to use nullable type to overcome this exception.

Answer 1

select row.Field<int?>("Presently_Available")

Answer 2

you have to make int accept null value => int?

row.Field<int?>("Presently_Available") == null ? 0 : row.Field<int>("Presently_Available") ;

and this is a link for the Nullable Types