object cannot be cast from dbnull to other types in datatable compute method

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Hello,

int sum = Convert.ToInt32(dt.Compute("SUM(Amount)", "Section>0"));

I want to use aggregate function sum() to get total amount from datatable for specific conditions,but the above statement throws error object cannot be cast from dbnull to other types

Posted 14-Oct-15 23:09pm

Parag Sudhir Chaudhari

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[no name] 15-Oct-15 5:20am

It seems Amount column value is NULL for some records in your DataTable dt object. You can overcome the exception putting 0 instead of NULL.

If it doesn't resolve your problem, please provide code how data is coming to your DataTable.

7045Jeegnesh 15-Oct-15 5:46am

Yes Manas_Kumar Is right:

dt.defaultview.rowfilter="Amount is Not Null"

int sum = Convert.ToInt32(dt.defaultview.Totable.Compute("SUM(Amount)", "Section>0"));

try This

Parag Sudhir Chaudhari 16-Oct-15 1:37am

Thanks its working now

W∴ Balboos, GHB 15-Oct-15 6:48am

More Options:

You can handle this on the SQL side using ISNULL(...,...) so that you never return a null from the query.

You can test the value in a prior statement for (dbnull) and then handle it as you see fit.

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Sinisa Hajnal · Answer 1 · 2015-10-15T00:47:00

Solution 1

Try this:

C#

int sum = 0;
object calc = dt.Compute("SUM(ISNULL(Amount, 0))", "Section>0");
bool converted = Integer.TryParse(calc, sum);
if (!converted) // some message;
else
//work normally

Posted 15-Oct-15 0:47am

Sinisa Hajnal