Question

我有一个WCF客户端，我遇到了问题。
我不时会遇到这个例外：Cannot access a disposed object。这就是我打开连接的方式：

private static LeverateCrmServiceClient crm = null;

public static CrmServiceClient Get(string crmCertificateName)
        {

            if (crm != null)
            {
                crm.Close();
            }
            try 
            {
                crm = new LeverateCrmServiceClient("CrmServiceEndpoint");
                crm.ClientCredentials.ClientCertificate.SetCertificate(
                               StoreLocation.LocalMachine,
                               StoreName.My,
                               X509FindType.FindBySubjectName,
                               crmCertificateName);
            }
            catch (Exception e) 
            {
                log.Error("Cannot access CRM ", e);
                throw;
            }
            return crm;
        }

如您所见，我每次都关闭并重新打开连接。您认为可能是什么问题？

堆栈：

System.ServiceModel.Security.MessageSecurityException: Message security verification failed. ---> System.ObjectDisposedException: Cannot access a disposed object.
Object name: 'System.ServiceModel.Security.SymmetricSecurityProtocol'.
  at System.ServiceModel.Channels.CommunicationObject.ThrowIfClosedOrNotOpen()
  at System.ServiceModel.Security.MessageSecurityProtocol.VerifyIncomingMessage(Message& message, TimeSpan timeout, SecurityProtocolCorrelationState[] correlationStates)
  --- End of inner exception stack trace ---

Server stack trace:
  at System.ServiceModel.Security.MessageSecurityProtocol.VerifyIncomingMessage(Message& message, TimeSpan timeout, SecurityProtocolCorrelationState[] correlationStates)
  at System.ServiceModel.Channels.SecurityChannelFactory`1.SecurityRequestChannel.ProcessReply(Message reply, SecurityProtocolCorrelationState correlationState, TimeSpan timeout)
  at System.ServiceModel.Channels.SecurityChannelFactory`1.SecurityRequestChannel.Request(Message message, TimeSpan timeout)
  at System.ServiceModel.Channels.ServiceChannel.Call(String action, Boolean oneway, ProxyOperationRuntime operation, Object[] ins, Object[] outs, TimeSpan timeout)
  at System.ServiceModel.Channels.ServiceChannelProxy.InvokeService(IMethodCallMessage methodCall, ProxyOperationRuntime operation)
  at System.ServiceModel.Channels.ServiceChannelProxy.Invoke(IMessage message)

Exception rethrown at [0]:
  at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg)
  at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type)
  at Externals.CrmService.ICrmService.GetTradingPlatformAccountDetails(Guid ownerUserId, String organizationName, String businessUnitName, Guid tradingPlatformAccountId)
  at MyAppName.Models.ActionsMetadata.Trader.BuildTrader(Guid tradingPlatformAccountId) in C:\Users\X\Documents\Visual Studio 2010\Projects\MyAppName\MyAppName\Models\ActionsMetadata\Trader.cs:line 120
  at MyAppName.Models.ActionsMetadata.Trader.Login(String accountNumber, String password) in C:\Users\X\Documents\Visual Studio 2010\Projects\MyAppName\MyAppName\Models\ActionsMetadata\Trader.cs:line 48
  at MyAppName.Models.ActionsMetadata.Handlers.LoginHandler.Handle(StepHandlerWrapper wrapper) in C:\Users\X\Documents\Visual Studio 2010\Projects\MyAppName\MyAppName\Models\ActionsMetadata\Handlers\LoginHandler.cs:line 23
  at MyAppName.Models.ActionsMetadata.Handlers.HandlerInvoker.Invoke(IAction brokerAction, ActionStep actionStep, Dictionary`2 stepValues, HttpContext httpContext, BaseStepDataModel model) in C:\Users\X\Documents\Visual Studio 2010\Projects\MyAppName\MyAppName\Models\ActionsMetadata\Handlers\StepServerInoker.cs:line 42
  at MyAppName.Controllers.LoginController.Login(String step) in C:\Users\X\Documents\Visual Studio 2010\Projects\MyAppName\MyAppName\Controllers\LoginController.cs:line 35
  at lambda_method(Closure , ControllerBase , Object[] )
  at System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary`2 parameters)
  at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters)
  at System.Web.Mvc.ControllerActionInvoker.<>c__DisplayClass15.<InvokeActionMethodWithFilters>b__12()
  at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodFilter(IActionFilter filter, ActionExecutingContext preContext, Func`1 continuation)
  at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodWithFilters(ControllerContext controllerContext, IList`1 filters, ActionDescriptor actionDescriptor, IDictionary`2 parameters)
  at System.Web.Mvc.ControllerActionInvoker.InvokeAction(ControllerContext controllerContext, String actionName)

Answer 1

从该堆栈跟踪中，我假设您有一个ASP.NET MVC应用程序，其中一些代码调用Get方法来获取CrmServiceClient对象，然后继续调用该方法上的各种方法{ {1}}对象。例如，部分登录过程就是这样做的。

CrmServiceClient方法的工作方式是，每次调用它时，它将首先关闭它之前返回的Get对象（无论它是否仍在使用），然后创建并返回一个新的。

想象一下，两个用户几乎在同一时间尝试登录您的应用程序 - 彼此之间的毫秒数。处理第一个用户登录的线程调用CrmServiceClient并获取其Get对象，然后毫秒后处理第二个用户的登录调用CrmServiceClient的线程导致第一个线程的Get要关闭的对象。但是，第一个线程仍在运行，现在当它尝试在其CrmServiceClient对象上调用方法时，它会获得CrmServiceClient。

“正如您所看到的，我每次都关闭并重新打开连接。”

目前使用System.ObjectDisposedException: Cannot access a disposed object方法的代码不是实现此目的的好方法。您应该让调用者负责关闭（或处置）Get对象，您应该将CrmServiceClient方法重命名为Get或Open以建议这一点。调用者应该使用Create语句来确保对象被关闭/处置，而不管出现的任何异常：

using

无法访问已处置的对象 - wcf客户端

1 个答案: