一段时间以来,我一直在敲打这个问题(并且知道这是愚蠢的事情).
我正在下载带有ProgressBar的文件,它显示正常,但我如何从ReadAsync流中获取数据以保存？
public static readonly int BufferSize = 4096;
int receivedBytes = 0;
int totalBytes = 0;
WebClient client = new WebClient();
byte[] result;
using (var stream = await client.OpenReadTaskAsync(urlToDownload))
{
byte[] buffer = new byte[BufferSize];
totalBytes = Int32.Parse(client.ResponseHeaders[HttpResponseHeader.ContentLength]);
for (;;)
{
result = new byte[stream.Length];
int bytesRead = await stream.ReadAsync(buffer,buffer.Length);
if (bytesRead == 0)
{
await Task.Yield();
break;
}
receivedBytes += bytesRead;
if (progessReporter != null)
{
DownloadBytesProgress args =
new DownloadBytesProgress(urlToDownload,receivedBytes,totalBytes);
progessReporter.Report(args);
}
}
}
我试图通过结果var,但这显然是错误的.在这个漫长的周日下午,我会感激不尽.
解决方法
下载的内容位于byte []缓冲区变量中：
int bytesRead = await stream.ReadAsync(buffer,buffer.Length);
来自Stream.ReadAsync：
buffer:
Type: System.Byte[]
The buffer to write the data into.
你永远不会使用你的结果变量.不确定为什么它在那里.
编辑
所以问题是如何阅读流的完整内容.您可以执行以下操作：
public static readonly int BufferSize = 4096;
int receivedBytes = 0;
WebClient client = new WebClient();
using (var stream = await client.OpenReadTaskAsync(urlToDownload))
using (MemoryStream ms = new MemoryStream())
{
var buffer = new byte[BufferSize];
int read = 0;
totalBytes = Int32.Parse(client.ResponseHeaders[HttpResponseHeader.ContentLength]);
while ((read = await stream.ReadAsync(buffer,buffer.Length)) > 0)
{
ms.Write(buffer,read);
receivedBytes += read;
if (progessReporter != null)
{
DownloadBytesProgress args =
new DownloadBytesProgress(urlToDownload,totalBytes);
progessReporter.Report(args);
}
}
return ms.ToArray();
}
}
