C#在网络流上设置WriteTimeout / ReadTimeout没有区别吗？
C#在网络流上设置WriteTimeout / ReadTimeout没有区别吗？
提问于 2019-02-21 20:58:11
我的Xamarin.Forms应用程序中有以下方法代码
using (TcpClient client = new TcpClient(ip, port))
using (NetworkStream stream = client.GetStream())
{
byte[] messageBytes = PrepareMessageBytes();
//
// Setting these seam to have no effect
//
stream.WriteTimeout = (int)TimeSpan.FromSeconds(10).TotalMilliseconds;
stream.ReadTimeout = (int)TimeSpan.FromSeconds(10).TotalMilliseconds;
//
// I have set read and write timeouts above but when
// hitting this line, app hangs indefinitely?
// I would expect that after 10 seconds, a IOException
// will be thrown
await stream.WriteAsync(messageBytes, 0, messageBytes.Length);
stream.Flush();
byte[] buffer = new byte[1024];
StringBuilder builder = new StringBuilder();
int bytesRead = 0;
while (stream.DataAvailable)
{
bytesRead = await stream.ReadAsync(buffer, 0, buffer.Length);
builder.AppendFormat("{0}", Encoding.ASCII.GetString(buffer, 0, bytesRead));
}
string msg = receivedMessage.ToString();
} 上面，我已经将写和读超时设置为10秒。我知道我的代码挂在电话里：
等待stream.WriteAsync(.)
，但我希望10秒后，会抛出一个IOException。基于MS文档，异步写入/读取不是这种情况。
如何设置调用WriteAsync / ReadAsync方法的超时？
更新--基于评论的第二次尝试
根据Stephen的评论，我更新了代码并将其封装到try..catch中以处理OperationCancelledException。，但这造成了比以前更多的问题，应用程序大部分时间仍将挂起：
try
{
using (TcpClient client = new TcpClient(ip, port))
using (NetworkStream stream = client.GetStream())
using (var writeCts = new CancellationTokenSource(TimeSpan.FromSeconds(10)))
{
byte[] messageBytes = PrepareMessageBytes();
await stream.WriteAsync(messageBytes, 0, messageBytes.Length, writeCts.Token);
await stream.FlushAsync();
byte[] buffer = new byte[1024];
StringBuilder builder = new StringBuilder();
int bytesRead = 0;
while (stream.DataAvailable)
{
using (var readCts = new CancellationTokenSource(TimeSpan.FromSeconds(10)))
bytesRead = await stream.ReadAsync(buffer, 0, buffer.Length, readCts.Token);
builder.AppendFormat("{0}", Encoding.ASCII.GetString(buffer, 0, bytesRead));
}
string msg = receivedMessage.ToString();
}
catch (OperationCancelledException ex)
{
Debug.WriteLine(ex.Message);
}回答 1
Stack Overflow用户
发布于 2019-02-22 14:35:03
如何设置调用WriteAsync / ReadAsync方法的超时？
使用接受CancellationToken参数的重载：
using (TcpClient client = new TcpClient(ip, port))
using (NetworkStream stream = client.GetStream())
using (var writeCts = new CancellationTokenSource(TimeSpan.FromSeconds(10)))
{
byte[] messageBytes = PrepareMessageBytes();
await stream.WriteAsync(messageBytes, 0, messageBytes.Length, writeCts.Token);
await stream.FlushAsync();
byte[] buffer = new byte[1024];
StringBuilder builder = new StringBuilder();
int bytesRead = 0;
while (stream.DataAvailable)
{
using (var readCts = new CancellationTokenSource(TimeSpan.FromSeconds(10)))
bytesRead = await stream.ReadAsync(buffer, 0, buffer.Length, readCts.Token);
builder.AppendFormat("{0}", Encoding.ASCII.GetString(buffer, 0, bytesRead));
}
string msg = receivedMessage.ToString();
}我希望10秒后，会抛出一个IOException。
当使用取消令牌时，期望得到一个OperationCanceledException。从技术上讲，取消令牌可以用于各种各样的取消场景--代码决定不再需要完成操作，用户手动取消操作，或者超时。OperationCanceledException是泛型异常类型，意思是“取消”。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/54816114
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