There are three column in the datatable A,B and C
. Now each column is type of decimal
. Now I am doing like dt.Columns["A"].Expression="B+C";
to make addition of Column B's record and column C's record. Now if there is any value of B or C
is null
then addition of B and C will be null like B's value is 3 and C's value is null
for first row then B+C(3+null)
will be null
which is not appropriate, the result of addition should be 3
.If I replace 0
instead of null
then it will be ok.But whereever there is null value in the records it should be remain it is and it should not be replaced by 0
.That is null value should not be replaced by 0
and when addition of null value is done with any decimal value null
value should be considered as 0
.
Is it possible,how can we do this ?
EDIT
See the following answer
where
dt.Rows[0]["B"] = DBNull.Value;
but I have problem like according to my code I can not assign DBNull.Value
directly dt.Rows[0]["B"] = DBNull.Value;
I have to store it in one variable of type object
like
Object obj;
obj=DBNull.Value
and then that value goes to the table.Then it gives error like null value can not be stored to the column B.
Try something like this
dt.Columns["A"].Expression = "ISNULL(B, 0) + ISNULL(C, 0)";
Full working test:
DataTable dt = new DataTable();
dt.Columns.Add("A", typeof(decimal));
dt.Columns.Add("B", typeof(decimal));
dt.Columns.Add("C", typeof(decimal));
dt.Rows.Add();
dt.Rows[0]["B"] = DBNull.Value;
dt.Rows[0]["C"] = 3;
dt.Columns["A"].Expression = "ISNULL(B, 0) + ISNULL(C, 0)";
Console.WriteLine(dt.Rows[0]["A"]);