Queuing Threads from the Generic Queue Class [VB.NET/C# Examples by AceInfinity]

AceInfinity · May 20, 2012

Here's an example I put together for someone on MSDN who wanted to be able to easily create a queue of methods to start new threads, and be able to start them one after another in order. Thought i'd share it here as well, as this can be very useful for managing a Thread Queue. Thread syncrhonization in an application is valuable, and can get somewhat complex as well...

Code:

Public Class Form1

    Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
        
    End Sub

    Private qt As Queue(Of Thread)
    Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
        qt = New Queue(Of Thread)
        qt.Enqueue(New Thread(AddressOf method1))
        qt.Enqueue(New Thread(AddressOf method2))
        qt.Enqueue(New Thread(AddressOf method3))
        qt(0).Start()
    End Sub

    Private Sub UpdateQueue()
        qt.Dequeue()
        Sync.Variable = qt.Count
    End Sub

    Private Sub method1()
        Console.WriteLine("method1")
        Thread.Sleep(3000)
        UpdateQueue()
    End Sub

    Private Sub method2()
        Console.WriteLine("method2")
        Thread.Sleep(3000)
        UpdateQueue()
    End Sub

    Private Sub method3()
        Console.WriteLine("method3")
        Thread.Sleep(3000)
        UpdateQueue()
    End Sub

    Private WithEvents Sync As New SyncQueueCount
    Private Sub VariableChanged(ByVal QCount As Integer) Handles Sync.VariableChanged
        If QCount > 0 Then
            qt(0).Start()
        Else
            MessageBox.Show("Queue Finished")
        End If
    End Sub

End Class

Public Class SyncQueueCount
    Private S_Int As Integer
    Public Event VariableChanged(ByVal value As Integer)

    Public Property Variable() As Integer
        Get
            Variable = S_Int
        End Get
        Set(ByVal value As Integer)
            S_Int = value
            RaiseEvent VariableChanged(S_Int)
        End Set
    End Property
End Class

C#: Ignore my project namespace

Code:

namespace CSharp_Tester
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            SyncQueue.VariableChanged += new SyncQueueCount._VariableChanged(VariableChanged);
        }

        private SyncQueueCount SyncQueue = new SyncQueueCount();
        private Queue<Thread> qt;
        private void button1_Click(object sender, EventArgs e)
        {
            qt = new Queue<Thread>();
            qt.Enqueue(new Thread(method1));
            qt.Enqueue(new Thread(method2));
            qt.Enqueue(new Thread(method3));
            qt.ElementAt(0).Start();
        }

        private void UpdateQueue()
        {
            qt.Dequeue();
            SyncQueue.Variable = qt.Count();
        }

        private void method1()
        {
            Console.WriteLine("method1");
            Thread.Sleep(3000);
            UpdateQueue();
        }

        private void method2()
        {
            Console.WriteLine("method2");
            Thread.Sleep(3000);
            UpdateQueue();
        }

        private void method3()
        {
            Console.WriteLine("method3");
            Thread.Sleep(3000);
            UpdateQueue();
        }

        private void VariableChanged(int QCount)
        {
            if (QCount > 0)
                qt.ElementAt(0).Start();
            else
                MessageBox.Show("Queue Finished");
        }

    }

}

public class SyncQueueCount
{
    private int S_Int;
    public delegate void _VariableChanged(int value);
    public event _VariableChanged VariableChanged;

    public int Variable
    {
        get { return S_Int; }
        set {
            S_Int = value;
            VariableChanged(S_Int);
        }
    }
}

If anybody here is interested in how this works, just let me know, it was the most basic example I could fit together as a demonstration.

Note:

Code:

Thread.Sleep(3000);

Thread sleep was put in there to show a noticable delay in which to demonstrate that there is in fact a queued process going on here with starting each thread one after another.

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Queuing Threads from the Generic Queue Class [VB.NET/C# Examples by AceInfinity]

AceInfinity

Emeritus, Contributor