Question

What I am trying to do is, creating an application which executes some action. there should be maximum of 10 threads running.

I have the following code, which works fine. I need to send a parameter to “Somework” procedure. How can I do that?

Module Module1
    Sub Main()
        Dim Task As New Action(AddressOf SomeWork)

        dim I as integer

        for i=1 to 20
        If RunningThread < 10 Then
            Task.BeginInvoke(AddressOf Callback, Nothing)
            Threading.Interlocked.Increment(RunningThread)
        Else
            SyncLock (Lock)
                tasks.Enqueue(Task)
            End SyncLock
        End If
        next

        Console.ReadLine()
    End Sub

    Private tasks As New Queue(Of action)
    Private RunningThread As Integer
    Private Lock As New Object

    Dim I As Integer = 0

    Private Sub SomeWork()
        I += 1
        Console.WriteLine(I & " doing some work - begin :: " & Now.ToString)
        Threading.Thread.Sleep(10000)
        Console.WriteLine(I & " doing some work - end :: " & Now.ToString)
    End Sub

    Private Sub Callback(ByVal o As Object)
        If tasks.Count > 0 Then
            Dim Task As Action
            SyncLock (Lock)
                Task = tasks.Dequeue
            End SyncLock
            Task.BeginInvoke(AddressOf Callback, Nothing)
        Else
            Threading.Interlocked.Decrement(RunningThread)
        End If
    End Sub
End Module

Kindly help.

Thanks

Answer 1

You can achieve your requirements easily using the Task Parallel Library (TPL) using Parallel.ForEach. Use a constructor that allows you to specify a ParallelOptions parameter and set the MaxDegreeOfParallelism to your thread limit.