调用Windows服务中托管的WCF服务的最佳实践

Question

EndpointAddress _endpoint = new EndpointAddress("net.tcp://" + szWord_Operation_Ip + "/CalcService");
var channel = new ChannelFactory<Process_Word_Document.ICalcService>(_binding, _endpoint);
var _client = channel.CreateChannel();
_client.Update_Document_Properties(szFilePath);

OR

EndpointAddress _endpoint = new EndpointAddress("net.tcp://" + szWord_Operation_Ip + "/CalcService");
using (Process_Word_Document.CalcServiceClient _client = new Process_Word_Document.CalcServiceClient(_binding, _endpoint))
  _client.Update_Document_Properties(szFilePath); 

服务......

[ServiceContract]
public interface ICalcService
{
    [OperationContract]
    Boolean Process_Word_Document(string szFilePath);

}


public class CalcService : ICalcService
{
 public bool Process_Word_Document(string szFilePath)
 {
   //.....Code
 }
}

我只是想知道这些调用方法之间的区别  哪一个更好＆amp;这将给我更好的表现。