我正在尝试学习如何使用新的asp.net 4.5异步处理程序以及Request.GetBufferlessInputStream来将图像上传到磁盘中。这段代码可以运行并将文件写入磁盘，但是图像损坏了，我不确定原因在哪里。以下是我使用的代码：
public class UploadHandler : HttpTaskAsyncHandler
{
public override Task ProcessRequestAsync(HttpContext context)
{
// Gets a Stream object that can be used to read the
// incoming HTTP entity body, optionally disabling the
// request-length limit that is set in the MaxRequestLength property.
// This method provides an alternative to using the
// InputStream property. The InputStream property waits until the
// whole request has been received before it returns a Stream object.
// In contrast, the GetBufferlessInputStream method returns
// the Stream object immediately.
// You can use the method to begin processing the
// entity body before the complete contents of the
// body have been received.
// The entity body (or as much of it as you request and has
// been received) is returned only when you use the object that
// is returned by this method to read the stream, by calling
// methods such as the Read method. You use parameters of the
// Read method to specify how much of the entity body to read.
// This method can be useful if the request is uploading a
// large file and you want to begin accessing the file contents
// before the upload is finished.
// However, you should only use this method for scenarios where
// you want to take over all processing of the entity body.
// This means that you cannot use this method from an .aspx page,
// because by the time an .aspx page runs, the entity body
// has already been read.
using (Stream input = context.Request.GetBufferlessInputStream(true))
using (var file = new FileStream("C:\\myfile.jpg", FileMode.Create,
FileAccess.Write, FileShare.Write))
{
input.CopyTo(file);
}
context.Response.ContentType = "text/plain";
return context.Response.Output.WriteAsync("Done");
}
}