C++/CX - DataReader超出范围例外
我有以下代码可以打开一个文件,并且它大部分时间都可以运行一次。之后,我得到异常抛出,我不知道问题隐藏在哪里。我已经尝试了几天,但没有运气。C++/CX - DataReader超出范围例外
String^ xmlFile = "Assets\\TheXmlFile.xml";
xml = ref new XmlDocument();
StorageFolder^ InstallationFolder = Windows::ApplicationModel::Package::Current->InstalledLocation;
task<StorageFile^>(
InstallationFolder->GetFileAsync(xmlFile)).then([this](StorageFile^ file) {
if (nullptr != file) {
task<Streams::IRandomAccessStream^>(file->OpenAsync(FileAccessMode::Read)).then([this](Streams::IRandomAccessStream^ stream)
{
IInputStream^ deInputStream = stream->GetInputStreamAt(0);
DataReader^ reader = ref new DataReader(deInputStream);
reader->InputStreamOptions = InputStreamOptions::Partial;
reader->LoadAsync(stream->Size);
strXml = reader->ReadString(stream->Size);
MessageDialog^ dlg = ref new MessageDialog(strXml);
dlg->ShowAsync();
});
}
});
错误触发在这部分代码:
strXml = reader->ReadString(stream->Size);
我收到以下错误:
First-chance exception at 0x751F5B68 in XmlProject.exe: Microsoft C++ exception: Platform::OutOfBoundsException^at memory location 0x02FCD634. HRESULT:0x8000000B The operation attempted to access data outside the valid range
WinRT的信息:操作试图超出了有效访问数据范围
就像我说的,它第一次正常工作,但之后,我得到了呃ROR。我尝试分离datareader的流和缓冲区,并试图刷新流,但没有结果。
我也在Microsoft C++论坛上问过这个问题,并在user“Viorel_”上写道,我设法让它工作。维奥雷尔下面说:
Since LoadAsync does not perform the operation immediately, you should probably add a corresponding “.then”. See some code: https://social.msdn.microsoft.com/Forums/windowsapps/en-US/94fa9636-5cc7-4089-8dcf-7aa8465b8047 . This sample uses “create_task” and “then”: https://code.msdn.microsoft.com/vstudio/StreamSocket-Sample-8c573931/sourcecode (file Scenario1.xaml.cpp, for example).
我不得不在task<Streams::IRandomAccessStream^>
内容分开和独立的任务分裂它。
我重建我的代码,我现在有以下几点:
String^ xmlFile = "Assets\\TheXmlFile.xml";
xml = ref new XmlDocument();
StorageFolder^ InstallationFolder = Windows::ApplicationModel::Package::Current->InstalledLocation;
task<StorageFile^>(
InstallationFolder->GetFileAsync(xmlFile)).then([this](StorageFile^ file) {
if (nullptr != file) {
task<Streams::IRandomAccessStream^>(file->OpenAsync(FileAccessMode::Read)).then([this](Streams::IRandomAccessStream^ stream)
{
IInputStream^ deInputStream = stream->GetInputStreamAt(0);
DataReader^ reader = ref new DataReader(deInputStream);
reader->InputStreamOptions = InputStreamOptions::Partial;
create_task(reader->LoadAsync(stream->Size)).then([reader, stream](unsigned int size){
strXml = reader->ReadString(stream->Size);
MessageDialog^ dlg = ref new MessageDialog(strXml);
dlg->ShowAsync();
});
});
}
});