我们正在.NET Web应用程序中使用SqlDependency。在生产中间歇性地尝试调用Start时收到以下错误:
NullReferenceException - Object reference not set to an instance of an object.
Server stack trace:
at System.Object.GetType()
at log4net.Util.ReadOnlyPropertiesDictionary.GetObjectData(SerializationInfo info, StreamingContext context)
at System.Runtime.Serialization.Formatters.Binary.WriteObjectInfo.InitSerialize(Object obj, ISurrogateSelector surrogateSelector, StreamingContext context, SerObjectInfoInit serObjectInfoInit, IFormatterConverter converter, ObjectWriter objectWriter, SerializationBinder binder)
at System.Runtime.Serialization.Formatters.Binary.ObjectWriter.Write(WriteObjectInfo objectInfo, NameInfo memberNameInfo, NameInfo typeNameInfo)
at System.Runtime.Serialization.Formatters.Binary.ObjectWriter.Serialize(Object graph, Header[] inHeaders, __BinaryWriter serWriter, Boolean fCheck)
at System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.Serialize(Stream serializationStream, Object graph, Header[] headers, Boolean fCheck)
at System.Runtime.Remoting.Channels.CrossAppDomainSerializer.SerializeMessageParts(ArrayList argsToSerialize)
at System.Runtime.Remoting.Messaging.SmuggledMethodCallMessage..ctor(IMethodCallMessage mcm)
at System.Runtime.Remoting.Messaging.SmuggledMethodCallMessage.SmuggleIfPossible(IMessage msg)
at System.Runtime.Remoting.Channels.CrossAppDomainSink.SyncProcessMessage(IMessage reqMsg)
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 SqlDependencyProcessDispatcher.StartWithDefault(String connectionString, String& server, DbConnectionPoolIdentity& identity, String& user, String& database, String& service, String appDomainKey, SqlDependencyPerAppDomainDispatcher dispatcher, Boolean& errorOccurred, Boolean& appDomainStart)
at System.Data.SqlClient.SqlDependency.Start(String connectionString, String queue, Boolean useDefaults)
启动SqlDependency的代码很简单:
SqlDependency.Start(ConnectionStringHelper.GetDatabaseConnectionString(), null);
错误将log4net从v1升级到v2后首先出现。我们还收到了与SqlDependency无法找到log4net DLL相关的类似错误,已通过手动将DLL复制到C:\ Windows \ system32 \ inetsrv \
进行了纠正。SerializationException - Unable to find assembly 'log4net, Version=2.0.8.0, Culture=neutral, PublicKeyToken=669e0ddf0bb1aa2a'.
Server stack trace:
at System.Runtime.Serialization.Formatters.Binary.BinaryAssemblyInfo.GetAssembly()
at System.Runtime.Serialization.Formatters.Binary.ObjectReader.GetType(BinaryAssemblyInfo assemblyInfo, String name)
at System.Runtime.Serialization.Formatters.Binary.ObjectMap..ctor(String objectName, String[] memberNames, BinaryTypeEnum[] binaryTypeEnumA, Object[] typeInformationA, Int32[] memberAssemIds, ObjectReader objectReader, Int32 objectId, BinaryAssemblyInfo assemblyInfo, SizedArray assemIdToAssemblyTable)
at System.Runtime.Serialization.Formatters.Binary.__BinaryParser.ReadObjectWithMapTyped(BinaryObjectWithMapTyped record)
at System.Runtime.Serialization.Formatters.Binary.__BinaryParser.Run()
at System.Runtime.Serialization.Formatters.Binary.ObjectReader.Deserialize(HeaderHandler handler, __BinaryParser serParser, Boolean fCheck, Boolean isCrossAppDomain, IMethodCallMessage methodCallMessage)
at System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.Deserialize(Stream serializationStream, HeaderHandler handler, Boolean fCheck, Boolean isCrossAppDomain, IMethodCallMessage methodCallMessage)
at System.Runtime.Remoting.Channels.CrossAppDomainSerializer.DeserializeObject(MemoryStream stm)
at System.Runtime.Remoting.Messaging.SmuggledMethodCallMessage.FixupForNewAppDomain()
at System.Runtime.Remoting.Channels.CrossAppDomainSink.DoDispatch(Byte[] reqStmBuff, SmuggledMethodCallMessage smuggledMcm, SmuggledMethodReturnMessage& smuggledMrm)
at System.Runtime.Remoting.Channels.CrossAppDomainSink.DoTransitionDispatchCallback(Object[] args)
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 System._AppDomain.CreateInstance(String assemblyName, String typeName)
at System.Data.SqlClient.SqlDependency.CreateProcessDispatcher(_AppDomain masterDomain)
at System.Data.SqlClient.SqlDependency.ObtainProcessDispatcher()
at System.Data.SqlClient.SqlDependency.Start(String connectionString, String queue, Boolean useDefaults)
为什么SqlDependency与log4net有关系?
我认为仍然存在导致NullReferenceException - Object reference not set to an instance of an object.
的类型尚未解决。
堆栈跟踪中的最后两个语句说:
Server stack trace:
at System.Object.GetType()
at log4net.Util.ReadOnlyPropertiesDictionary.GetObjectData(SerializationInfo info, StreamingContext context)
我的猜测是log4net
也正在使用外部程序集引用,因此请尝试使用Fuslogvw.exe-log4net
来解决它(https://docs.microsoft.com/en-us/dotnet/framework/tools/fuslogvw-exe-assembly-binding-log-viewer)>
如果弹出另一个程序集作为参考,也将其复制到C:\Windows\system32\inetsrv\
。
关于为什么SqlDependency.Start时log4net引发错误的说明被称为