/// <summary>
        /// 测试调用 HelloWorld 存储过程.
        /// </summary>
        private static void TestHelloWorld()
        {
            using (TestEntities context = new TestEntities())
            {
                Console.WriteLine("调用 HelloWorld2 存储过程!  该存储过程 3个参数, 1个输入, 2个输出, 返回一个单行的结果集 ");

                ObjectParameter p1 = new ObjectParameter("vOutValue", "");
                ObjectParameter p2 = new ObjectParameter("vInOutValue", "");

                ObjectResult<string> result = context.HelloWorld2("Test", p1, p2);


                Console.WriteLine(result.FirstOrDefault());
                Console.WriteLine(p1.Value);
                Console.WriteLine(p2.Value);
            }
        }