Windows 7 issue - Invalid async Begin method signature for method GetAsync in ServiceContract type xxxxx.ServiceBusHost.DispatcherService. Your begin method must take an AsyncCallback and an object as the last two arguments and return an IAsyncResult.

[mothupally]

Hi, We are trying to connect to Azure ServiceBus using WebAPI and the solution works well in Windows Server 2012, however the same reports below error while running on Windows 7 box. Can you please suggest?

Error:
Invalid async Begin method signature for method GetAsync in ServiceContract type xxxxx.ServiceBusHost.DispatcherService. Your begin method must take an AsyncCallback and an object as the last two arguments and return an IAsyncResult.

at System.ServiceModel.Description.ServiceReflector.IsBegin(OperationContractAttribute opSettings, MethodInfo method)
at System.ServiceModel.Description.TypeLoader.CreateOperationDescription(ContractDescription contractDescription, MethodInfo methodInfo, MessageDirection direction, ContractReflectionInfo reflectionInfo, ContractDescription declaringContract)
at System.ServiceModel.Description.TypeLoader.CreateOperationDescriptions(ContractDescription contractDescription, ContractReflectionInfo reflectionInfo, Type contractToGetMethodsFrom, ContractDescription declaringContract, MessageDirection direction)
at System.ServiceModel.Description.TypeLoader.CreateContractDescription(ServiceContractAttribute contractAttr, Type contractType, Type serviceType, ContractReflectionInfo& reflectionInfo, Object serviceImplementation)
at System.ServiceModel.Description.TypeLoader.LoadContractDescriptionHelper(Type contractType, Type serviceType, Object serviceImplementation)
at System.ServiceModel.Description.ContractDescription.GetContract(Type contractType, Object serviceImplementation)
at System.ServiceModel.ServiceHost.CreateDescription(IDictionary`2& implementedContracts)
at System.ServiceModel.ServiceHostBase.InitializeDescription(UriSchemeKeyedCollection baseAddresses)
at System.ServiceModel.ServiceHost.InitializeDescription(Type serviceType, UriSchemeKeyedCollection baseAddresses)
at System.ServiceModel.ServiceHost.InitializeDescription(Object singletonInstance, UriSchemeKeyedCollection baseAddresses)
at System.ServiceModel.ServiceHost..ctor(Object singletonInstance, Uri[] baseAddresses)
at xxxxx.ServiceBusHost.HttpServiceBusServer.OpenAsync()