使用web服务时出错

我有一个客户端提供的web服务，我需要使用它。

我使用WCFTestClient测试了web服务。,我确认服务正常。

现在，我想使用c#代码来使用web服务。我添加了web服务的url作为服务引用。

我将服务引用命名为PG_WS。我完成了一部分代码。

当我尝试调试代码时，当我到达

这一行时:

 PG_WS.ServiceSoapClient ws = new PG_WS.ServiceSoapClient();

我得到一个错误说:

    Message: System.InvalidOperationException: Could not find default endpoint 
element that references contract 'PG_WS.ServiceSoap' in the ServiceModel client configuration section. This might be because no configuration file was found for your application, or because no endpoint element matching this contract could be found in the client element.
       at System.ServiceModel.Description.ConfigLoader.LoadChannelBehaviors(ServiceEndpoint serviceEndpoint, String configurationName)
       at System.ServiceModel.ChannelFactory.ApplyConfiguration(String configurationName, Configuration configuration)
       at System.ServiceModel.ChannelFactory.ApplyConfiguration(String configurationName)
       at System.ServiceModel.ChannelFactory.InitializeEndpoint(String configurationName, EndpointAddress address)
       at System.ServiceModel.ChannelFactory`1..ctor(String endpointConfigurationName, EndpointAddress remoteAddress)
       at System.ServiceModel.ConfigurationEndpointTrait`1.CreateSimplexFactory()
       at System.ServiceModel.ConfigurationEndpointTrait`1.CreateChannelFactory()
       at System.ServiceModel.ClientBase`1.CreateChannelFactoryRef(EndpointTrait`1 endpointTrait)
       at System.ServiceModel.ClientBase`1.InitializeChannelFactoryRef()
       at System.ServiceModel.ClientBase`1..ctor()

我一直被困在这一点上，不知道错误意味着什么，我下一步该怎么做。如果你有什么想法请告诉我。