Dodo,
In addition to the other comments.
Here is a an example I posted February 2005 of a Worker class using a
ManualResetEvent to control suspending & resuming.
Public Class Worker
Public Delegate Sub Work()
Private ReadOnly m_work As Work
Private ReadOnly m_arg As Object
Private ReadOnly m_event As ManualResetEvent
Private ReadOnly m_thread As Thread
<ThreadStatic()> _
Private Shared m_current As Worker
Public Sub New(ByVal work As Work, ByVal arg As Object, ByVal name
As String)
m_work = work
m_arg = arg
m_event = New ManualResetEvent(True)
m_thread = New Thread(AddressOf Start)
m_thread.Name = name
m_thread.IsBackground = True
m_thread.Start()
End Sub
Private Sub Start()
m_current = Me
m_work.Invoke()
End Sub
Public Shared ReadOnly Property CurrentWorker() As Worker
Get
Return m_current
End Get
End Property
Public ReadOnly Property Arg() As Object
Get
Return m_arg
End Get
End Property
Public ReadOnly Property Name() As String
Get
Return m_thread.Name
End Get
End Property
Public Sub Suspend()
If Thread.CurrentThread Is m_thread Then
Throw New InvalidOperationException("Suspend should not be
called from the worker thread!")
End If
m_event.Reset()
End Sub
Public Sub [Resume]()
If Thread.CurrentThread Is m_thread Then
Throw New InvalidOperationException("Resume should not be
called from the worker thread!")
End If
m_event.Set()
End Sub
Public Sub WaitForTermination()
If Thread.CurrentThread Is m_thread Then
Throw New InvalidOperationException("WaitForTermination
should not be called from the worker thread!")
End If
m_thread.Join()
End Sub
Public Sub CheckSuspend()
If Not Thread.CurrentThread Is m_thread Then
Throw New InvalidOperationException("CheckSuspend should
only be called from the worker thread!")
End If
m_event.WaitOne()
End Sub
End Class
To see how it works try something like:
Private Sub Work()
For index As Integer = 1 To 50
Worker.CurrentWorker.CheckSuspend()
Debug.WriteLine(index, Worker.CurrentWorker.Name)
Dim value As Double = DirectCast(Worker.CurrentWorker.Arg,
Double)
Thread.Sleep(TimeSpan.FromSeconds(value))
Next
End Sub
Public Sub Main()
Dim worker1 As New Worker(AddressOf Work, 0.25, "worker1")
Dim worker2 As New Worker(AddressOf Work, 0.5, "worker2")
Dim worker3 As New Worker(AddressOf Work, 0.75, "worker3")
Debug.WriteLine("Pausing 5 seconds", "Main")
Thread.Sleep(TimeSpan.FromSeconds(5))
worker1.Suspend()
Debug.WriteLine("Pausing 5 seconds", "Main")
Thread.Sleep(TimeSpan.FromSeconds(5))
worker2.Suspend()
Debug.WriteLine("Pausing 5 seconds", "Main")
Thread.Sleep(TimeSpan.FromSeconds(5))
worker3.Suspend()
Debug.WriteLine("Pausing 1 seconds", "Main")
Thread.Sleep(TimeSpan.FromSeconds(1))
worker1.Resume()
worker2.Resume()
worker3.Resume()
Debug.WriteLine("Waiting for Termination", "Main")
worker1.WaitForTermination()
worker2.WaitForTermination()
worker3.WaitForTermination()
End Sub
The above sample was initially posted in a thread titled "Technique for
Pausing Worker Thread" in the microsoft.public.dotnet.languages.vb newsgroup
between 21 Jan 2005 & 23 Jan 2005.
Hope this helps
Jay
|
| In the .NET Framwrok 2.0 the methods
|
| Suspend();
| Resume();
|
| of the Thread Class are marked as Obsolete
|
| [ObsoleteAttribute("Thread.Resume has been deprecated. Please use other
| classes in System.Threading, such as Monitor, Mutex, Event, and Semaphore,
to
| synchronize Threads or protect resources.
|
http://go.microsoft.com/fwlink/?linkid=14202", false)]
| public void Resume();
|
| How if I have a backgroud thread ( say a very long and time consuming
| simulation ) and I want to easily give the use the ability to suspend it
to
| use his pc for a while without that load ?
| And then resume it ?
| I do beleve that this is not the the right way to sincornize Threads but
| what if you want just to suspend a thread.
|
|
