SetDataSource******** to CrystalReport

[C# Programming]

Hi to all.

I have designed report and by wizard, i have set SetDataSource******** to server and I want to change SetDataSource******** at runtime by giving parameter values for userid,password,databasename,server.

I am using this way how to connect at my local sqlexpress server in runtime:
crReportDocument.SetDatabaseLogon("username","pass",".\\sqlexpress","databasename");
When I run application I get always login prompt ********

Any help is appraciated.

Regards.