为什么我的 NamedPipeServerStream 不等待?
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25-09-2019 - |
题
我正在使用 NamedPipeServerStream 在两个进程之间进行通信。这是我初始化和连接管道的代码:
void Foo(IHasData objectProvider)
{
Stream stream = objectProvider.GetData();
if (stream.Length > 0)
{
using (NamedPipeServerStream pipeServer = new NamedPipeServerStream("VisualizerPipe", PipeDirection.Out, 1, PipeTransmissionMode.Byte, PipeOptions.Asynchronous))
{
string currentDirectory = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location);
string uiFileName = Path.Combine(currentDirectory, "VisualizerUIApplication.exe");
Process.Start(uiFileName);
if(pipeServer.BeginWaitForConnection(PipeConnected, this).AsyncWaitHandle.WaitOne(5000))
{
while (stream.CanRead)
{
pipeServer.WriteByte((byte)stream.ReadByte());
}
}
else
{
throw new TimeoutException("Pipe connection to UI process timed out.");
}
}
}
}
private void PipeConnected(IAsyncResult e)
{
}
但它似乎永远不会等待。我经常遇到以下异常:
系统.InvalidOperationException:管道尚未连接。at System.IO.Pipes.PipeStream.CheckWriteOperations() at System.IO.Pipes.PipeStream.WriteByte(Byte value) at PeachesObjectVisualizer.Visualizer.Show(IDialogVisualizerService windowService, IVisualizerObjectProvider objectProvider)
我认为等待返回后一切都应该准备就绪。
如果我使用 pipelineServer.WaitForConnection() 一切正常,但如果管道未连接则挂起应用程序不是一个选项。
解决方案
你需要打电话 结束等待连接.
var asyncResult = pipeServer.BeginWaitForConnection(PipeConnected, this);
if (asyncResult.AsyncWaitHandle.WaitOne(5000))
{
pipeServer.EndWaitForConnection(asyncResult);
// ...
}
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