There is already an open DataReader associated with this Command which must be closed first.

Multiple Active Result Sets (MARS) is a new feature that works with SQL Server 2005 to allow the execution of multiple batches on a single connection. To access multiple result sets on previous versions of SQL Server using SqlDataReader objects, a separate SqlConnection object must be used with each SqlCommand object. However, when MARS is enabled for use with SQL Server 2005, each command object used adds a session to the connection.

RESOLVED

After some investigation it turned out I needed to add the MARS (Multiple Active Result Sets) to the Web.Config and set the value to True.

All works fine!

And NO I dont have a Datareader declared explicity - Im using EF.

"There is already an open DataReader associated with this Command which must be closed first"

Your error message says it

if you have used datareader with a connection and left datareader open and trying to use the same connection you will get that error


Check you code again, their must be a datareader

The db.Dispose() didnt work : (

After reading some forums it is suggested I retrieve all my results\return values first, store in a list\collection and then do something with that list?

In fact looking at my SubmitOrder method which opens a connection to the DB, there is a db.SaveChanges(); call at the end but no db.Dispose(); which I think could be the issue here...

This is my code

List orderDetails;
            var orderId = usersShoppingCart.SubmitOrder(User.Identity.Name, out orderDetails);


            int totalQuantity = 0;


            foreach (OrderDetail od in orderDetails)
            {
                totalQuantity += od.Quantity;
            }

Its as if there needs to be a closing or end after the foreach or even a pause before the next part of the method gets called, which in this case redirects to PayPal.

Thanks
Steven

Im not using DataReader anywhere in my app.

Each method which accesses the DB has a using block which I thought automatically disposes when finished?

If you are using a DataReader you need to close it after reading

MyDataReaderObject.Close();