Using application roles with DataReader - sql-server

Question

I have an application that should use an application role from the database.
I'm trying to make this work with queries that are actually run using Subsonic (2).
To do this, I created my own DataProvider, which inherits from Subsonic's SqlDataProvider.
It overrides the CreateConnection function, and calls sp_appsetrole to set the application role after the connection is created.
This part works fine, and I'm able to get data using the application role.
The problem comes when I try to unset the application role. I couldn't find any place in the code where my provider is called after the query is done, so I tried to add my own, by changing SubSonic code. The problem is that Subsonic uses a data reader. It loads data from the data reader, and then closes it.
If I unset the application role before the data reader is closed, I get an error saying: There is already an open DataReader associated with this Command which must be closed first.
If I unset the application role after the data reader is closed, I get an error saying ExecuteNonQuery requires an open and available Connection. The connection's current state is closed.
I can't seem to find a way to close the data reader without closing the connection.

Answer 1

Do you have to use the role for every query?
If not you can use a SharedDbConnectionScope()
using(var scope = new SharedDbConnectionScope())
{
// within this using block you have a single connection
// that isn't closed until scope.Dispose() is called
// (happens automatically while leaving this block)
// and you have access to scope.CurrentConnection
// Do your init stuff
SetRole(scope.CurrentConnection);
var product = new Product();
product.Code = "12345";
product.Save();
// Revert to normal
UnsetRole(scope.CurrentConnection);
}

Answer 2

The problem is that Subsonic executes its reader with CloseConnection.
If I make it not close the connection I can unset the application role after the reader is closed.

Answer 3

May be you can subscribe to the event like this:
Connection.StateChange += new System.Data.StateChangeEventHandler(Connection_StateChange);
And then do some actions according to the new state of this connection:
if(e.CurrentState== System.Data.ConnectionState.Open)
dbworker.ExecuteCommand("EXEC sp_setapprole application, 'password'");