为什么我会从 WSDL 调用中得到 System.InvalidOperationException，但不会从对另一个服务的同一调用中得到 System.InvalidOperationException？

我创建了服务来获取各个客户的国家/地区详细信息，但是在托管该服务时我遇到了此异常。我正在使用基本的 http 绑定。

An ExceptionDetail, likely created by IncludeExceptionDetailInFaults=true, whose value is:
System.InvalidOperationException: An exception was thrown in a call to a 
WSDL export extension:   
  System.ServiceModel.Description.DataContractSerializerOperationBehavior
  contract: http://tempuri.org/:IReferenceDataService ----> 
     System.Runtime.Serialization.InvalidDataContractException: 
     Type 'Pariwaar.BusinessObject.CountryBO' cannot be serialized. 
     Consider marking it with the DataContractAttribute attribute, 
     and marking all of its members you want serialized with the 
     DataMemberAttribute attribute. See the Microsoft .NET Framework 
     documentation for other supported types.
   at System.Runtime.Serialization.DataContract.DataContractCriticalHelper.ThrowInvalidDataContractException(String message, Type type)
   at System.Runtime.Serialization.DataContract.DataContractCriticalHelper.CreateDataContract(Int32 id, RuntimeTypeHandle typeHandle, Type type)
   at System.Runtime.Serialization.DataContract.DataContractCriticalHelper.GetDataContractSkipValidation(Int32 id, RuntimeTypeHandle typeHandle, Type type)
   at System.Runtime.Serialization.DataContract.GetDataContract(RuntimeTypeHandle typeHandle, Type type, SerializationMode mode)
   at System.Runtime.Serialization.DataContractSet.GetDataContract(Type clrType)
   at System.Runtime.Serialization.DataContractSet.GetItemTypeDataContract(CollectionDataContract collectionContract)
   at System.Runtime.Serialization.DataContractSet.AddCollectionDataContract(CollectionDataContract collectionDataContract)
   at System.Runtime.Serialization.DataContractSet.Add(XmlQualifiedName name, DataContract dataContract)
   at System.Runtime.Serialization.DataContractSet.Add(Type type)
   at System.Runtime.Serialization.XsdDataContractExporter.Export(Type type)
   at System.ServiceModel.Description.MessageContractExporter.ExportType(Type type, String partName, String operationName, XmlSchemaType& xsdType)
   at System.ServiceModel.Description.DataContractSerializerMessageContractExporter.ExportBody(Int32 messageIndex, Object state)
   at System.ServiceModel.Description.MessageContractExporter.ExportMessage(Int32 messageIndex, Object state)
   at System.ServiceModel.Description.MessageContractExporter.ExportMessageContract()
   at System.ServiceModel.Description.DataContractSerializerOperationBehavior.System.ServiceModel.Description.IWsdlExportExtension.ExportContract(WsdlExporter exporter, WsdlContractConversionContext contractContext)
   at System.ServiceModel.Description.WsdlExporter.CallExtension(WsdlContractConversionContext contractContext, IWsdlExportExtension extension)
   --- End of inner ExceptionDetail stack trace ---
   at System.ServiceModel.Description.WsdlExporter.CallExtension(WsdlContractConversionContext contractContext, IWsdlExportExtension extension)
   at System.ServiceModel.Description.WsdlExporter.CallExportContract(WsdlContractConversionContext contractContext)
   at System.ServiceModel.Description.WsdlExporter.ExportContract(ContractDescription contract)
   at System.ServiceModel.Description.WsdlExporter.ExportEndpoint(ServiceEndpoint endpoint, XmlQualifiedName wsdlServiceQName)
   at System.ServiceModel.Description.WsdlExporter.ExportEndpoints(IEnumerable`1 endpoints, XmlQualifiedName wsdlServiceQName)
   at System.ServiceModel.Description.ServiceMetadataBehavior.MetadataExtensionInitializer.GenerateMetadata()
   at System.ServiceModel.Description.ServiceMetadataExtension.EnsureInitialized()
   at System.ServiceModel.Description.ServiceMetadataExtension.HttpGetImpl.InitializationData.InitializeFrom(ServiceMetadataExtension extension)
   at System.ServiceModel.Description.ServiceMetadataExtension.HttpGetImpl.GetInitData()
   at System.ServiceModel.Description.ServiceMetadataExtension.HttpGetImpl.TryHandleDocumentationRequest(Message httpGetRequest, String[] queries, Message& replyMessage)
   at System.ServiceModel.Description.ServiceMetadataExtension.HttpGetImpl.ProcessHttpRequest(Message httpGetRequest)
   at System.ServiceModel.Description.ServiceMetadataExtension.HttpGetImpl.Get(Message message)
   at SyncInvokeGet(Object , Object[] , Object[] )
   at System.ServiceModel.Dispatcher.SyncMethodInvoker.Invoke(Object instance, Object[] inputs, Object[]& outputs)
   at System.ServiceModel.Dispatcher.DispatchOperationRuntime.InvokeBegin(MessageRpc& rpc)
   at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage5(MessageRpc& rpc)
   at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage4(MessageRpc& rpc)
   at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage3(MessageRpc& rpc)
   at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage2(MessageRpc& rpc)
   at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage1(MessageRpc& rpc)
   at System.ServiceModel.Dispatcher.MessageRpc.Process(Boolean isOperationContextSet)

I have businessobject[datamember]在另一个项目中。我在这里引用了它的dll。

你可以查看我的课程

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.Text;
using Pariwaar.BusinessObject;
using Pariwaar.DataAccessLayer;

namespace Pariwaar.WCFServices.SVC
{
    // NOTE: If you change the class name "ReferenceDataService" here, you must also update the reference to "ReferenceDataService" in Web.config.
    public class ReferenceDataService : IReferenceDataService
    {
        ReferenceData objDAL = new ReferenceData();

        public List<CountryBO> GetCountry()
        { return objDAL.GetCountry(); }

        public List<StateBO> GetState(int CountryId)
        { return objDAL.GetState(CountryId); }

        public List<CityBO> GetCity(int StateId)
        { return objDAL.GetCity(StateId); }
    }
}

为什么这在另一个 WCF 服务中工作正常，但在另一个服务中却出现错误？

嗯，错误很明显：

System.Runtime.Serialization.InvalidDataContractException： 类型 'Pariwaar.BusinessObject.CountryBO'无法序列化。考虑标记 它与数据契约属性属性，并标记其所有 您想要序列化的成员 DataMemberAttribute 属性。看 微软.NET框架 其他受支持的文档 类型。

您显然正在使用数据类型Pariwaar.BusinessObject.CountryBO作为 WCF 服务方法之一的参数或返回值，但该类没有[DataContract]其上的属性。

请参阅 MSDN 文档使用数据合约 http://Pariwaar.BusinessObject.CountryBO了解数据协定以及如何使您的对象可供 WCF 使用。看到这个博客文章 - WCF 基础知识：数据契约 http://www.arquitecturadesoftware.org/blogs/hugobatista/archive/2005/11/06/wcf-basics-data-contracts.aspx对于同一主题的另一种观点。

所有复杂类型（例如类）都应使用 [DataContract] 进行标记，所有要包含在 WCF 消息中的字段都应使用 [DataMember] 进行标记：

[DataContract]
class Pariwaar.BusinessObject.CountryBO
{
   [DataMember]
   string CountryName { get; set; }

   [DataMember]
   string CountryCurrency { get; set; }

   [DataMember]
   string CountryISOCode { get; set; }

   ........
}

Marc