如何取消悬挂线程？ [英] How cancel hanging thread?

问题描述

Hello,

i'm interested in how you can cancel hanging thread?

What I have tried:

<pre>Example:

        Public Sub FileStreamWrite(ByVal pFs As FileStream, ByVal pByPrint As Byte())

            pFs.Write(pByPrint, 0, pByPrint.Length)

        End Sub


 Dim processThreads As ProcessThreadCollection = Process.GetCurrentProcess.Threads
                        Dim newThread1 As New Thread(CType(Sub() FileStreamWrite(fs, pByPrint), ThreadStart))
                        newThread1.IsBackground = True
                        newThread1.Start()
                        Do
                            Application.DoEvents()
                            If Now.TimeOfDay.Subtract(timeStart).TotalSeconds > 10 Then
                                Select Case ShowQuestionMessage(MethodBase.GetCurrentMethod(), "Do you want to continue?", "", MessageBoxButtons.RetryCancel, MessageBoxDefaultButton.Button1)
                                    Case DialogResult.Cancel
                                        processThreads = Process.GetCurrentProcess.Threads
                                        Dim a = OpenThread(1, False, CType(processThreads(processThreads.Count - 1).Id, UInteger))
                                        Dim b = GetNativeThreadId(newThread1)
                                        Dim w = OpenThread(1, False, CType(newThread1.ManagedThreadId, UInteger))
                                        TerminateThread(w, 1)
                                        processThreads = Process.GetCurrentProcess.Threads
                                        isRepeat = False                
                                        Return
                                    Case Else
                                        timeStart = Now.TimeOfDay
                                End Select
                            End If
                        Loop While newThread1.IsAlive AndAlso isRepeat

推荐答案

你不需要使用P / Invoke调用 - Thread 类有一个 Abort 方法。



但你也不应该使用它：如何在.NET中停止线程（以及为什么Thread.Abort是邪恶的） [ ^ ]



这会好得多使用 Async 方法，结合 CancellationToken ：

使用Async和Await进行异步编程（Visual Basic）| Microsoft Docs [ ^ ]

托管线程中的取消| Microsoft Docs [ ^ ]

There's no need for you to use P/Invoke calls - the Thread class has an Abort method.

But you shouldn't use that either: How To Stop a Thread in .NET (and Why Thread.Abort is Evil)[^]

It would be much better to use an Async method, combined with a CancellationToken:
Asynchronous Programming with Async and Await (Visual Basic) | Microsoft Docs[^]
Cancellation in Managed Threads | Microsoft Docs[^]

Public Function FileStreamWrite(ByVal pFs As Stream, ByVal pByPrint As Byte(), ByVal cancellationToken As CancellationToken) As Task
    Return pFs.WriteAsync(pByPrint, 0, pByPrint.Length, cancellationToken)
End Function

Using cts As New CancellationTokenSource()
    Dim task As Task = FileStreamWrite(fs, pByPrint, cts.Token)
    Dim pollPeriod As TimeSpan = TimeSpan.FromSeconds(10)
    
    While Not task.Wait(pollPeriod)
        Select Case ShowQuestionMessage(...)
            Case DialogResult.Cancel
                cts.Cancel()
                task.Wait()
        End Select
    End While
End Using

你好，



我测试了你的，我们正在等待任务。等等（）。但我希望在这种情况下停止这项任务。

Hello,

I tested yours and we are waiting for the task.Wait () also. But I want to stop this task in this case.

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