Using C# Code Convert To Zero If DBNULL

Question

Hello

I get this error

how to convert zero in c# code behind

Thanks

Answer 1

Hi @RAVI,

I tested your code using test data and did not reproduce your issue.

But you can try using the code below.

 object objCompute = new_tablez.Compute("sum(Value)", null);
 if (objCompute != DBNull.Value)
 {
     subtotal_Account = Convert.ToDouble(objCompute);
 }
 else
 {
     subtotal_Account = 0;
 }

Best regards,
Lan Huang

---

If the answer is the right solution, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

Answer 2

In my opinion, the easiest solution is adding CASE expression to the SQL script that returns the record set. If NULL is found then return a zero. This way you don't have to add complexity to the code behind.

DECLARE @NullTest TABLE (MyColumn INT);
INSERT INTO @NullTest(MyColumn)
VALUES	(null),
		(1),
		(null),
		(2)
SELECT MyColumn
FROM @NullTest
SELECT	CASE WHEN MyColumn IS NULL 
			THEN 0 
			ELSE MyColumn 
		END AS MyColumn
FROM @NullTest

If you really want to update the code behind then write an "if" condition that checks for DBNull. Keep in mind you asked this same question recently and the community provided source code that checks for DBNull. The logic must execute before the Sum function. You did not share how the result set is fetched but the syntax is very simple.

if (myDataReader["columnName"] == System.DBNull.Value)
{
    myvar = 0;
}
else 
{   
   myvar = myDataReader["columnName"]
}

Or you could use the ternary conditional operator

Again, I would update the SQL not the code behind.