Question

我正在为Windows商店构建一个电子书管理器，我已经在我的一个类上实现了IUriToStreamResolver接口。我用它来打开一个epub。代码如下：

public IAsyncOperation<IInputStream> UriToStreamAsync(Uri uri)
{
     if(uri == null)
     {
         throw new Exception();
     }

     string path = uri.AbsolutePath;

     return GetContent(path).AsAsyncOperation();
}


private async Task<IInputStream> GetContent(string path)
{
     path = path.TrimStart('/');
     var file = await StorageApplicationPermissions.FutureAccessList.GetFileAsync(App.token);
     var stream = await file.OpenAsync(FileAccessMode.Read);
     var archive = new ZipArchive(stream.AsStream());
     var entry = archive.Entries.Where(a => a.FullName == path);
     var entryStream = entry.First().Open();
     return entryStream.AsInputStream();
}

从GetContent()方法返回后，我得到一个神秘的System.InvalidCast异常。我启用了混合调试，我可以获得更多信息，但它不是很有帮助。

这是堆栈：

combase.dll！RoFailFastWithErrorContextInternal（long，unsigned long，struct _STOWED_EXCEPTION_INFORMATION_V1 * * const）未知       combase.dll!_RoFailFastWithErrorContext@4（）未知       twinapi.appcore.dll！Windows :: ApplicationModel :: Core :: CoreApplication :: ForwardLocalError（struct IRestrictedErrorInfo *）未知       twinapi.appcore.dll！Windows :: ApplicationModel :: Core :: CoreApplicationFactory :: ForwardLocalError（struct IRestrictedErrorInfo *）Unknown       combase.dll！CallErrorForwarder（void *，int，struct IRestrictedErrorInfo *）未知       combase.dll!_RoReportUnhandledError@4（）未知       mscorlib.ni.dll！63eb2d62（）未知       [下面的框架可能不正确和/或缺失，没有为mscorlib.ni.dll加载符号]
      [管理到原生过渡]
      mscorlib.dll！System.Runtime.InteropServices.WindowsRuntime.WindowsRuntimeMarshal.RoReportUnhandledError（System.Runtime.InteropServices.WindowsRuntime.IRestrictedErrorInfo error）未知       mscorlib.dll！System.Runtime.InteropServices.WindowsRuntime.WindowsRuntimeMarshal.ReportUnhandledError（System.Exception e）未知       System.Runtime.WindowsRuntime.dll！System.Threading.WinRTSynchronizationContext.Invoker.InvokeCore（）未知       System.Runtime.WindowsRuntime.dll！System.Threading.WinRTSynchronizationContext.Invoker.InvokeInContext（object thisObj）Unknown       mscorlib.dll！System.Threading.ExecutionContext.RunInternal（System.Threading.ExecutionContext executionContext，System.Threading.ContextCallback callback，object state，bool preserveSyncCtx）Unknown       mscorlib.dll！System.Threading.ExecutionContext.Run（System.Threading.ExecutionContext executionContext，System.Threading.ContextCallback callback，object state，bool preserveSyncCtx）Unknown       System.Runtime.WindowsRuntime.dll！System.Threading.WinRTSynchronizationContext.Invoker.Invoke（）未知       [原产于管理过渡]
      Windows.UI.dll！Windows :: UI :: Core :: CDispatcher :: ProcessInvokeItem（）第794行C ++       Windows.UI.dll！Windows :: UI :: Core :: CDispatcher :: WaitAndProcessMessages（void * hEventWait）C ++       Windows.UI.dll！Windows :: UI :: Core :: CDispatcher :: ProcessEvents（Windows :: UI :: Core :: CoreProcessEventsOption options = CoreProcessEventsOption_ProcessUntilQuit）Line 390 C ++       Windows.UI.Xaml.dll！DirectUI :: FrameworkView :: Run（）未知       twinapi.appcore.dll！Windows :: ApplicationModel :: Core :: CoreApplicationView :: Run（void）未知       twinapi.appcore.dll！Windows :: Foundation :: Collections :: Internal :: HashMap，struct Windows :: Foundation :: Collections :: Internal :: DefaultEqualityPredicate，struct Windows :: Foundation :: Collections :: Internal :: DefaultLifetimeTraits， struct Windows :: ApplicationModel :: Core :: Details :: SmugglableInterfaceLifetimeTraits，struct Windows :: Foundation :: Collections :: Internal :: HashMapOptions，0,1,0＆gt; ＆gt; ::删除（unsigned int）未知       SHCore.dll！Microsoft :: WRL :: RuntimeClass，类CScalingInfoBase，struct ICurrentWindowChangeListener，类Microsoft :: WRL :: FtmBase，类Microsoft :: WRL :: Details :: Nil，class Microsoft :: WRL :: Details :: Nil ，类Microsoft :: WRL :: Details :: Nil，类Microsoft :: WRL :: Details :: Nil，类Microsoft :: WRL :: Details :: Nil，class Microsoft :: WRL :: Details :: Nil＆gt;：：`vector deletion destructor'（unsigned int）未知       kernel32.dll！@ BaseThreadInitThunk @ 12（）未知       ntdll.dll！__ RtlUserThreadStart（）未知       ntdll.dll！__ RtlUserThreadStart @ 8（）未知

这是唯一的本地人： $ exceptionstack

    [9 Frames, combase.dll!_RoOriginateLanguageException@12()] 
    [0] combase.dll!_RoOriginateLanguageException@12() void*
    [1] mscorlib.ni.dll!63eb2c8a()  void*
    [2] mscorlib.ni.dll!63f4ffa2()  void*
    [3] mscorlib.ni.dll!63f4fd61()  void*
    [4] System.Runtime.WindowsRuntime.ni.dll!506ef9df() void*
    [5] System.Runtime.WindowsRuntime.ni.dll!506ef965() void*
    [6] mscorlib.ni.dll!63823156()  void*
    [7] System.Runtime.WindowsRuntime.ni.dll!506ef934() void*
    [8] Windows.UI.ni.dll!50e1ff16()    void*

非常感谢任何帮助或指示！

Answer 1

我修好了但我不确定它是最佳解决方案。如果有人想提出改进建议我就是游戏。

在我的GetContent()方法中，我做了以下更改：

private async Task<IInputStream> GetContent(string path)
    {
        try
        {
            path = path.TrimStart('/');
            var file = await StorageApplicationPermissions.FutureAccessList.GetFileAsyn(App.token);

            var archive = new ZipArchive(await file.OpenStreamForReadAsync(),ZipArchiveMode.Read);
            var entry = archive.GetEntry(path);
            var contents = new byte[entry.Length];
            var entryStream = entry.Open();
            var tempFile = await ApplicationData.Current.LocalFolder.CreateFileAsync("temp.xhtml",CreationCollisionOption.ReplaceExisting);
            var decompressedStream = await tempFile.OpenStreamForWriteAsync();
            await entryStream.CopyToAsync(decompressedStream, (int)entry.Length);
            await decompressedStream.FlushAsync();
            decompressedStream.Dispose();
            var returnFile = await ApplicationData.Current.LocalFolder.GetFileAsync("temp.xhtml");
            var returnStream = await returnFile.OpenSequentialReadAsync();
            return returnStream;
        }
        catch (Exception e)
        {

            throw;
        }
    }

System.InvalidCast异常Windows运行时

1 个答案: