Populate Crystal Report with multiple Datasources from Database using C# in ASP.Net

when i am using two datatable, report does not display data

FeeReceipt cr=new FeeReceipt;
cr.setDataSource(dt1);
cr.setDataSource(dt2);

I have two datatable dt1 and dt2

what i am doing wrong, can u provide me som link for doing this?

THANKS IN ADVANCE