Problem using default value of report parameter 1 to validate parameter 2 passed in to report

Question

I am having a problem with an SSRS report using the default value of report parameter 1 to validate parameter 2 passed in to report (via C#) instead of using the value of parameter 1 that is also passed into the report.  Here are the
simplified details:
Using SSDT, SQL Server 2008 R2
SSRS report has 2 parameters:
P1 -- text, hidden, default value 'R1', ... front-end C# code can pass 'R2' or 'R1'
P2 -- text, allows multiple values, list of available values provided by stored procedure (sproc_list) that takes P1 value as a parameter.  Hence, sproc_list either provides a list for P1 = 'R1' or P1 = 'R2'.
List for P1 = 'R1' is 'A', 'B', 'C'
List for P1 = 'R2' is 'A', 'B', 'D'
Values for P1 and P2 can be passed in via C# to the report.
The C# front-end displays 2 report choices to the user, R1 and R2, where both choices call the same RDL; but choice R1 passes in 'R1' for P1, and the choice R2 passes in 'R2' for P1.
Upon a users 1st time use of the report no parameters are passed in.  Then when the user exits the report, the parameter value for P2 that was chosen is saved off to a file for R1 or R2, and used the next time the user selects the report.
Everything always works fine for report R1 since the default value for P1 is 'R1'.
When R2 is chosen and the user selects 'D' as the value for P2, runs the report, then exits, the P2 value of 'D' for R2 is saved to a file.  When the user returns the next day to run report R2, 'R2' is passed for P1, and 'D' is passed for P2.
This is when the problem occurs.  The value of 'D' for P2 is validated against a list generated for P2 based on the default value of 'R1' for parameter P1.  Hence, SSRS considers 'D' an invalid value for P2 and blanks out the P2 parameter. 
The user can then use the drop down list for P2 and choose 'D', but this defeats the purpose of saving the parameter values to be used the next time.
Why is the stored procedure that provides a list of available values for parameter P2 using the default value of 'R1' for parameter P1 instead of using the value of 'R2' passed into the report for parameter P1?

Answer 1

Hi Tom,
Sorry for my delay.
If I understand correctly, you have two parameter in your report. It is a couple of cascading parameter. If we have choose ‘R1’ of P1, the P2 values is A, B, C. ‘R2’ of P1, corresponding P2 values is A, B, D. What your requirement is to save the end use
select option of these two parameters.
In SSRS, if we have configure the parameter with default value. When we run the report, the parameter will fill with the default value to filter data. If we want to save the last status we are render the report, we need to update the default value of P1.
If we are query the default value from database, if possible, we can
update the database try to resolve the issue.  Alternatively, we can set the dynamic default value for the parameter.
Hope this helps.
Regards,
Alisa Tang
Alisa Tang
TechNet Community Support