<connectionStrings>
<add name="connectionStringName"
    connectionString="Data Source=NAMESQLEXPRESS;Initial Catalog=DbName;Integrated Security=True"
    providerName="System.Data.SqlClient" />

SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["connectionStringName"].ConnectionString);
            SqlCommand cmd;
            con.Open();
            cmd = new SqlCommand("proc_name", con);
            cmd.CommandType = CommandType.StoredProcedure;
            cmd.Parameters.Add(new SqlParameter("@id", id));
            cmd.ExecuteReader();
            con.Close();