WCF中如何用代码加入MEX元数据

配置代码如下：直接使用配置文件能正常运行！

<?xml version="1.0"?>
<configuration>
  <system.serviceModel>
    <services>
      <service name="ServiceImplementation.MessageService">
        <host>
          <baseAddresses>
            <add baseAddress="net.Tcp://localhost:8732/"/>
            <add baseAddress="http://localhost:8889/"/>
          </baseAddresses>
        </host>
        <endpoint address="Tcp" binding="netTcpBinding" contract="Services.IMessage"/>
        <endpoint address="Http" binding="basicHttpBinding" contract="Services.IMessage">
          <identity>
            <dns value="localhost"/>
          </identity>
        </endpoint>
        <endpoint address="mex" binding="mexTcpBinding" contract="IMetadataExchange"/>
        <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange"/>
      </service>
    </services>
    <behaviors>
      <serviceBehaviors>
        <behavior>
          <serviceMetadata/>
        </behavior>
      </serviceBehaviors>
    </behaviors>
  </system.serviceModel>
<startup><supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5"/></startup></configuration>

使用代码如下：vs2012 net4.5
string tcpHostName = "localhost";
            int tcpPort = 8732;
            string tcpEndPstr = @"net.tcp://{0}:{1}";
            tcpEndPstr = string.Format(tcpEndPstr, tcpHostName, tcpPort.ToString());
            Uri tcpUri = new Uri(tcpEndPstr);

            string httpHostName = "localhost";
            int httpPort = 8889;
            string httpEndPstr = @"http://{0}:{1}";
            httpEndPstr = string.Format(httpEndPstr, httpHostName, httpPort.ToString());
            Uri httpUri = new Uri(httpEndPstr);

            Uri[] baseAddress = new Uri[] { httpUri, tcpUri };

            using (ServiceHost host = new ServiceHost(typeof(MessageService), baseAddress))
            {
                host.AddServiceEndpoint(typeof(IMessage),
                new BasicHttpBinding(),
                "Services.IMessage");

                host.AddServiceEndpoint(typeof(IMessage),
                    new NetTcpBinding(),
                    "Services.IMessage");

//*******   以下两句出现err:     **** 若注释点以下两行，服务不正常，没有响应
             //在服务 ServiceImplementation.MessageService 实现的协定列表中找不到协定名称 "IMetadataExchange"。
             //将 ServiceMetadataBehavior 添加到配置文件或直接添加到 ServiceHost，以启用对该协定的支持。

                host.AddServiceEndpoint(typeof(IMetadataExchange), MetadataExchangeBindings.CreateMexHttpBinding(), "mex");
                host.AddServiceEndpoint(typeof(IMetadataExchange), MetadataExchangeBindings.CreateMexTcpBinding(), "mex");

                if (host.Description.Behaviors.Find<ServiceMetadataBehavior>() == null)
                {
                    ServiceMetadataBehavior behavior = new ServiceMetadataBehavior();
                    //交换方式
                    behavior.HttpGetEnabled = true;
                    //元数据交换地址
                    behavior.HttpGetUrl = httpUri;
                    //将行为添加到宿主上
                    host.Description.Behaviors.Add(behavior);
                }

                host.Open();
WCF 元数据 WCF MEX 元数据代码配置 --------------------编程问答-------------------- 没人会吗？????? --------------------编程问答-------------------- 在app.config文件里加上：
<behaviors>
            <serviceBehaviors>
                <behavior name="">
                    <serviceMetadata httpGetEnabled="true" />
                    <serviceDebug includeExceptionDetailInFaults="true" />
                </behavior>
            </serviceBehaviors>
        </behaviors>

补充：.NET技术 ,  C#