我想有一个方法,它将一个System.IO.Stream作为输入并使用它将数据写入文件。到目前为止,我有以下几点:如何将数据从流保存到WinRT中的文件?
public async Task SaveStreamToFileX(Stream stream, string filePath, IProgress<long> progress)
{
var folder = await StorageFolder.GetFolderFromPathAsync(Path.GetDirectoryName(filePath));
var fileName = Path.GetFileName(filePath);
StorageFile file = await folder.CreateFileAsync(fileName, CreationCollisionOption.OpenIfExists);
var istream = stream.AsInputStream();
var canRead = stream.CanRead; //this returns true
using (var reader = new DataReader(istream))
{
using (IRandomAccessStream fileStream = await file.OpenAsync(FileAccessMode.ReadWrite))
{
using (IOutputStream outputStream = fileStream.GetOutputStreamAt(0))
{
using (DataWriter writer = new DataWriter(outputStream))
{
IBuffer buffer;
long readBytes = 0;
const int bufferSize = 8192;
while ((buffer = reader.ReadBuffer(bufferSize)).Length > 0) //exception System.Exception with message: Out of range ...
{
writer.WriteBuffer(buffer);
readBytes += bufferSize;
progress.Report(readBytes);
}
}
}
}
}
}
问题是,当我尝试读while循环(先读)数据的异常(超出范围)被抛出。流应该有数据。我不确定是否这么长的代码是坏的,如果有人有更好的解决方案,它会很好。 附注: 如果我尝试await reader.LoadAsync(50)
它返回50.我不确定LoadAsync应该做什么。也许我必须在阅读之前调用它以准备读取数据?我将进一步调查... 此外,Stream.CanRead返回true。