基础（暴露元数据交换节点）

1、原理

默认情况下，WCF服务不暴露MEX终结点

2、代码申明

   ServiceHost serviceHost =   new   ServiceHost(  typeof  (StockService),   new   Uri( "http://localhost:8000/EssentialWCF"  ));  
serviceHost.AddServiceEndpoint(  typeof  (IStockService),   new   BasicHttpBinding(),   ""  );
ServiceMetadataBehavior behavior = new ServiceMetadataBehavior();
 behavior.HttpGetEnabled = true;
 serviceHost.Description.Behaviors.Add(behavior);
   serviceHost.AddServiceEndpoint(  typeof  (IMetadataExchange), MetadataExchangeBindings.CreateMexHttpBinding(),   "mex"  );
   serviceHost.Open();

3、配置文件中申明

<?  xml   version  =  "1.0"   encoding  =  "utf-8"   ?>
<  configuration  >
    <  system.servicemodel  >
      <  services  >
        <  service   name  =  "EssentialWCF.StockService"   behaviorConfiguration  = "myServiceBehavior"  >
          <  host  >
            <  baseaddresses  >
              <  add   baseaddress  =  "http://localhost:8000/EssentialWCF"   />
            </  baseaddresses  >
          </  host  >
          <  endpoint   address  =  ""   binding  =  "basicHttpBinding"   contract  = "EssentialWCF.IStockService"   />
         <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange" />
        </  service  >
      </  services  >
      <behaviors>
      <serviceBehaviors>
        <behavior name="myServiceBehavior">
          <serviceMetadata httpGetEnabled="True" />
        </behavior>
      </serviceBehaviors>
    </behaviors>
    </  system.servicemodel  >
</  configuration  >