测试数据库服务器是否可用

在Sql连接字符串中设置Connect Timeout无效，只能通过Socket去判断

代码如下：

        /// <summary>
        /// 测试数据库服务器是否可用
        /// </summary>
        /// <param name="ip">服务器IP</param>
        /// <param name="port">服务器端口，一般是1433</param>
        /// <param name="timemout">设置超时时间，毫秒</param>
        /// <returns>如果数据库可用返回true，否则返回false</returns>
        static bool TestConn(string ip, int port, int timemout)
        {
            using (TcpClient client = new TcpClient())
            {

                ManualResetEvent mre = new ManualResetEvent(false);
                client.BeginConnect(ip, port, delegate(IAsyncResult res)
                {
                    if (client.Connected)
                    {
                        mre.Set();
                        Console.WriteLine("123");
                    }
                }, null);
                ThreadPool.QueueUserWorkItem(delegate(object obj) { Thread.Sleep(timemout); mre.Set(); });
                mre.WaitOne();
                if (!client.Connected)
                {
                    return false;
                }
                return true;
            }
        }

测试代码：

 
            DateTime begin = DateTime.Now;
            Console.WriteLine(TestConn("192.168.1.99", 1433, 2000));
            Console.WriteLine(DateTime.Now.Subtract(begin).TotalSeconds);