using (SqlConnection conn = new SqlConnection("Server=(local);DataBase=Northwind;Integrated Security=SSPI")) {
    conn.Open();

    // 1.  create a command object identifying the stored procedure
    SqlCommand cmd  = new SqlCommand("CustOrderHist", conn);

    // 2. set the command object so it knows to execute a stored procedure
    cmd.CommandType = CommandType.StoredProcedure;

    // 3. add parameter to command, which will be passed to the stored procedure
    cmd.Parameters.Add(new SqlParameter("@CustomerID", custId));

    // execute the command
    using (SqlDataReader rdr = cmd.ExecuteReader()) {
        // iterate through results, printing each to console
        while (rdr.Read())
        {
            Console.WriteLine("Product: {0,-35} Total: {1,2}",rdr["ProductName"],rdr["Total"]);
        }
    }
}