SSRS runtime error - The specified operation is not valid

Question

I found a similar post here, but it didn't solve my problem. so i re-post it.
i develop a report with vs2008. i have sql 2008 r2 on my local machine. when i preview the report on my local machine all fine. but when i deployed the report to sql 2008 ssrs server, i got "#Error" in my subtotal field. i opened the log file and found the
error message:
The specified operation is not valid. , ;
 Info: Microsoft.ReportingServices.ReportProcessing.ReportProcessingException: The specified operation is not valid.
i used a formular in the expression:
=Sum(IIf(Fields!flag.Value="S",Fields!Size.Value,0))
can someone help?
thanks

Answer 1

I want to make my problem more clear:
1. with the original formula: =Sum(IIf(Fields!Fundflag.Value="S",Fields!FundSize.Value,0)) works very well on my local machine with clicking on Preview. Once deploy to server, i got error.
2.Shahfaisal, your formula works on both side, but not the result i except. because the size field in sp unioned from different source. i only want to subtotal when flag is "S".
any help will be appreciated!
Try this
=Sum(IIF(IsNumeric(Fields!Size.Value)
AND Fields!flag.Value="S",Fields!Size.Value,0))