Asynchronous Programming in VB.NET

Example 4
Multithreading with the ThreadPool

1:  Private Delegate Sub AddInvoker(ByVal Elem As String)
2:  Private Sub AddElem(ByVal Elem As String)
3:    ListBox1.Items.Add(Elem)
4:  End Sub
5:  
6:  Private Sub ThreadedLoadList(ByVal state As Object)
7:    Dim I As Integer
8:  
9:    Try
10:     For I = 0 To 100000
11:       If (Me.InvokeRequired) Then
12:         Me.Invoke(New AddInvoker(AddressOf AddElem), _
13:          New Object() {I.ToString()})
14:       End If
15:     Next
16:   Catch
17:     Thread.CurrentThread.Join()
18:   End Try
19: 
20: End Sub
21: 
22: Private Sub Form1_Load(ByVal sender As System.Object, _
23:   ByVal e As System.EventArgs) Handles MyBase.Load
24:    
25:   AddHandler Application.Idle, AddressOf OnIdle
26: 
27:   ' 2: Demonstrates multithreaded approach using the thread pool
28:   ThreadPool.QueueUserWorkItem(New WaitCallback( _
29:     AddressOf ThreadedLoadList))
30: 
31:   Splash.Splash()
32: 
33: End Sub