我收到一个未知的异常，基本上下面的代码只循环了2000个项目，但是它需要几分钟才能到达opResult = uow.Commit();，并且此时它只是说它已经失败了。我完全不知所措。请帮忙吗？
public OperationResult PopulateReadingList(int readingListID, PrePopulateType dataType, GroupType[] groups)
{
var opResult = new OperationResult();
var listItemsToReturn = new List<ReadingListItem>();
try
{
Func<short?, Lookup_Countries> getCountry = c => NeptuneUnitOfWork.Countries.FindByID(c);
Func<string, bool> isEmptyString = string.IsNullOrEmpty;
using (var uow = NeptuneUnitOfWork)
{
var predicate = BuildPredicate(groups);
var items = uow.ReadingList.FindWhere(r=>r.ID==readingListID).SelectMany(m=> m.ReadingListMediaChannels).Where(predicate).ToList();
foreach (var readingListMediaChannel in items)
{
string value = string.Empty;
var country = getCountry(readingListMediaChannel.MediaChannel.CountryID);
switch (dataType)
{
case PrePopulateType.Country:
value = country != null?country.Name:string.Empty;
break;
case PrePopulateType.Region:
value = country != null?country.Lookup_SubRegions.Lookup_Regions.Name : string.Empty;
break;
case PrePopulateType.SubRegion:
value = country != null ? country.Lookup_SubRegions.Name:string.Empty;
break;
case PrePopulateType.MediaType:
value = readingListMediaChannel.MediaChannel.MediaType.Name;
break;
default:
break;
}
foreach (var group in groups)
{
switch (group)
{
case GroupType.Group1:
if (isEmptyString(readingListMediaChannel.Group1))
{
readingListMediaChannel.Group1 = value;
}
break;
case GroupType.Group2:
if (isEmptyString(readingListMediaChannel.Group2))
{
readingListMediaChannel.Group2 = value;
}
break;
case GroupType.Group3:
if (isEmptyString(readingListMediaChannel.Group3))
{
readingListMediaChannel.Group3 = value;
}
break;
case GroupType.Group4:
if (isEmptyString(readingListMediaChannel.Group4))
{
readingListMediaChannel.Group4 = value;
}
break;
case GroupType.Group5:
if (isEmptyString(readingListMediaChannel.Group5))
{
readingListMediaChannel.Group5 = value;
}
break;
default:
break;
}
}
listItemsToReturn.Add(new ReadingListItem
{
Group1 = readingListMediaChannel.Group1,
Group2 = readingListMediaChannel.Group2,
Group3 = readingListMediaChannel.Group3,
Group4 = readingListMediaChannel.Group4,
Group5 = readingListMediaChannel.Group5,
MediaCode = readingListMediaChannel.MediaChannel.NeptuneMediaID,
MediaID = readingListMediaChannel.MediaChannelID,
MediaName = readingListMediaChannel.MediaChannel.Name,
MediaTypeID = readingListMediaChannel.MediaChannel.MediaTypeID,
MediaTypeName = readingListMediaChannel.MediaChannel.MediaType.Name
});
}
opResult = uow.Commit();
}
}
catch (Exception ex)
{
Logger.Error(ex);
opResult.Success = false;
opResult.SetExceptionProperties(ex);
}
return opResult;
}
以下是调用此repo的控制器返回的错误消息：
Source Error:
An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.
Stack Trace:
[ObjectDisposedException: The ObjectContext instance has been disposed and can no longer be used for operations that require a connection.]
System.Data.Objects.ObjectContext.EnsureConnection() +11448512
System.Data.Objects.ObjectQuery`1.GetResults(Nullable`1 forMergeOption) +66
System.Data.Objects.DataClasses.EntityReference`1.Load(MergeOption mergeOption) +229
System.Data.Objects.DataClasses.RelatedEnd.DeferredLoad() +497
System.Data.Objects.Internal.LazyLoadBehavior.LoadProperty(TItem propertyValue, String relationshipName, String targetRoleName, Boolean mustBeNull, Object wrapperObject) +157
System.Data.Objects.Internal.<>c__DisplayClass7`2.<GetInterceptorDelegate>b__2(TProxy proxy, TItem item) +149
System.Data.Entity.DynamicProxies.ReadingListMediaChan_AA75ADD44097B0AF40DBB84D6E509EE9D2EA11F705268633DBD1D4743DEEA37B.get_MediaChannel() +151
[TargetInvocationException: Exception has been thrown by the target of an invocation.]
System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor) +0
System.Reflection.RuntimeMethodInfo.UnsafeInvokeInternal(Object obj, Object[] parameters, Object[] arguments) +229
System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture) +193
System.Reflection.MethodBase.Invoke(Object obj, Object[] parameters) +35
System.Web.Script.Serialization.JavaScriptSerializer.SerializeCustomObject(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat) +733
System.Web.Script.Serialization.JavaScriptSerializer.SerializeValueInternal(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat, MemberInfo currentMember) +1968
System.Web.Script.Serialization.JavaScriptSerializer.SerializeValue(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat, MemberInfo currentMember) +166
System.Web.Script.Serialization.JavaScriptSerializer.SerializeEnumerable(IEnumerable enumerable, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat) +195
System.Web.Script.Serialization.JavaScriptSerializer.SerializeValueInternal(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat, MemberInfo currentMember) +1923
System.Web.Script.Serialization.JavaScriptSerializer.SerializeValue(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat, MemberInfo currentMember) +166
System.Web.Script.Serialization.JavaScriptSerializer.Serialize(Object obj, SerializationFormat serializationFormat) +114
System.Web.Mvc.JsonResult.ExecuteResult(ControllerContext context) +282
System.Web.Mvc.<>c__DisplayClass1c.<InvokeActionResultWithFilters>b__19() +33
System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilter(IResultFilter filter, ResultExecutingContext preContext, Func`1 continuation) +726368
System.Web.Mvc.ControllerActionInvoker.InvokeActionResultWithFilters(ControllerContext controllerContext, IList`1 filters, ActionResult actionResult) +265
System.Web.Mvc.ControllerActionInvoker.InvokeAction(ControllerContext controllerContext, String actionName) +726324
System.Web.Mvc.Controller.ExecuteCore() +159
System.Web.Mvc.ControllerBase.Execute(RequestContext requestContext) +334
System.Web.Mvc.<>c__DisplayClassb.<BeginProcessRequest>b__5() +62
System.Web.Mvc.Async.<>c__DisplayClass1.<MakeVoidDelegate>b__0() +15
System.Web.Mvc.<>c__DisplayClasse.<EndProcessRequest>b__d() +52
System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +606
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +288
答案 0 :(得分：1)
你可以移动
Func<short?, Lookup_Countries> getCountry = c => NeptuneUnitOfWork.Countries.FindByID(c);
进入使用区块，并使用'uow'代替：
Func<short?, Lookup_Countries> getCountry = c => uow.Countries.FindByID(c);
答案 1 :(得分：0)
这通常发生在启用了EF 延迟加载并且在 DbContext或ObjectContext之后访问了需要延迟加载的属性时地布置。
有两种解决方法。修改代码以使上下文保持活动状态，直到完成实体，或禁用延迟加载并急切加载所需的所有内容。
当您使用 Web服务时，后一个选项通常是正确的选项。这是因为服务可能会返回实体。服务框架需要序列化这些实体，以便访问它们的所有属性。如果启用了延迟加载，则会抛出您正在看到的异常。