How To Explicitly Allocate An Sql Server Connection From The Connections Pool

Hello.

I have a db dal containing the following code:


SqlCommand cmd = new SqlCommand();

cmd.Connection = dbc;

cmd.CommandType = CommandType.StoredProcedure;

cmd.CommandText = "SOME STORED PROCEDURE";
.
.
.
declare some SqlParameters
.
.
.



dbc.Open();

cmd.ExecuteNonQuery();

dbc.Close();

This code, when concurrently running via several threads, yields the following exception:
"The connection was not closed. The connection's current state is open."


My questions are:
1. Why don't .Net allocate another connection from the pool (I try to only concurrently run 2 threads while there are 25 connections in the connection pool) ?
2. How can one explicitly allocate a connection?
3. How do you suggest to solve this problem without a mutex/monitor etc' on the 3 bold lines above and without BeginExequteNonQuery()?







Thank you !