System.ObjectDisposedException：必须为此操作打开存储

Question

IIS7 Windows2008 机器上有一个MVC4 应用程序。应用程序作为 ApplicationPoolIdentity 运行，并且相应的用户有权访问 ProgramData\IsolatedStorage 文件夹。 它还拥有 C:\Documents and Settings\Default User\Local Settings\Application Data\IsolatedStorage 文件夹的权限。 但在使用 openxml 编写大型 excel 文件时仍然收到异常。

ERROR MHDB.MvcApplication - System.ObjectDisposedException: Store must be open for this operation.
at System.IO.IsolatedStorage.IsolatedStorageFileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize, IsolatedStorageFile isf)
at System.IO.IsolatedStorage.IsolatedStorageFileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share, IsolatedStorageFile isf)
at MS.Internal.IO.Packaging.PackagingUtilities.SafeIsolatedStorageFileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share, ReliableIsolatedStorageFileFolder folder)
at MS.Internal.IO.Packaging.PackagingUtilities.CreateUserScopedIsolatedStorageFileStreamWithRandomName(Int32 retryCount, String& fileName)
at MS.Internal.IO.Packaging.SparseMemoryStream.EnsureIsolatedStoreStream()
at MS.Internal.IO.Packaging.SparseMemoryStream.SwitchModeIfNecessary()
at MS.Internal.IO.Packaging.CompressEmulationStream.Write(Byte[] buffer, Int32 offset, Int32 count)
at MS.Internal.IO.Packaging.CompressStream.Write(Byte[] buffer, Int32 offset, Int32 count)
at MS.Internal.IO.Zip.ProgressiveCrcCalculatingStream.Write(Byte[] buffer, Int32 offset, Int32 count)
at MS.Internal.IO.Zip.ZipIOModeEnforcingStream.Write(Byte[] buffer, Int32 offset, Int32 count)
at System.Xml.XmlUtf8RawTextWriter.FlushBuffer()
at System.Xml.XmlUtf8RawTextWriter.RawText(Char* pSrcBegin, Char* pSrcEnd)
at System.Xml.XmlUtf8RawTextWriter.WriteEndElement(String prefix, String localName, String ns)
at System.Xml.XmlWellFormedWriter.WriteEndElement()
at DocumentFormat.OpenXml.OpenXmlCompositeElement.WriteContentTo(XmlWriter w)
at DocumentFormat.OpenXml.OpenXmlElement.WriteTo(XmlWriter xmlWriter)
at DocumentFormat.OpenXml.OpenXmlCompositeElement.WriteContentTo(XmlWriter w)
at DocumentFormat.OpenXml.OpenXmlElement.WriteTo(XmlWriter xmlWriter)
at DocumentFormat.OpenXml.OpenXmlCompositeElement.WriteContentTo(XmlWriter w)
at DocumentFormat.OpenXml.OpenXmlPartRootElement.WriteTo(XmlWriter xmlWriter)
at DocumentFormat.OpenXml.OpenXmlPartRootElement.SaveToPart(OpenXmlPart openXmlPart)
at DocumentFormat.OpenXml.Packaging.OpenXmlPackage.SavePartContents()
at DocumentFormat.OpenXml.Packaging.OpenXmlPackage.Dispose(Boolean disposing)
at DocumentFormat.OpenXml.Packaging.OpenXmlPackage.Dispose()
at BL.OpenXML.Export(DataTable dt, Stream fs, Boolean createNewDocument)
at BL.BusinessLogic.CreateOpReport(UnitOfWork uow, String user, String orgapath, List`1 orgaids, Boolean isfin, String cycle, String startperiod, String endperiod)
at MHDB.Controllers.HomeController.GetFileAsStream()
at MHDB.Controllers.HomeController.ExportExcel()
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__DisplayClass13.<InvokeActionMethodWithFilters>b__10()
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)
at System.Web.Mvc.Controller.ExecuteCore()
at System.Web.Mvc.ControllerBase.Execute(RequestContext requestContext)
at System.Web.Mvc.Async.AsyncResultWrapper.<>c__DisplayClass1.<MakeVoidDelegate>b__0()
at System.Web.Mvc.MvcHandler.<>c__DisplayClass8.<BeginProcessRequest>b__3(IAsyncResult asyncResult)
at System.Web.Mvc.Async.AsyncResultWrapper.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar)
at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

感谢您的帮助！

Answer 1

由于 System.IO.Packaging，当您在内部写入大于 10MB 的文件时，它将不再将数据暂时保存在内存中，直到下次保存，但会切换到独立存储。这本身可能会导致很多问题，因为 IsolateStorage 并不意味着与同一应用程序的多个线程/多个实例一起使用，并且您也可能面临一些权限问题。

考虑到这是一个网络应用程序，我认为它可能与多个用户同时写入但都被解析到同一个独立存储位置有关..

我偶然发现了这个问题，同一个应用程序的多个实例都被解析到同一个位置。我仍在寻找一个优雅的解决方案，但我能够强制每个实例解析到不同的 IsolatedStorage 位置，并通过以下方式保持唯一：

var rootDirUserField= typeof(IsolatedStorageFile).GetField("s_RootDirUser", BindingFlags.NonPublic | BindingFlags.Static);
rootDirUserField.SetValue(null, "<unique location in isolated storage>");

这是因为静态字段 IsolatedStorageFile.s_RootDirUser 用于解析要使用的新目录。我的修复特定于用户 |域名 |装配范围。

我渴望找到更好的解决方案来解决这个问题。