Imports System
Imports System.Drawing
Imports System.Windows.Forms
Imports System.Threading
 
Public Class MyFormControl
    Inherits Form
 
    Delegate Sub AddListItem(ByVal myString As String)
    Delegate Function MessageDelegate(ByVal Message As String) As Boolean
    Public myDelegate As AddListItem
    Public myMessageDelegate As MessageDelegate
    Private myButton As Button
    Private myThread As Thread
    Private myListBox As ListBox
    Private myTextBox As TextBox
 
    Public Sub New()
        myButton = New Button()
        myListBox = New ListBox
        myTextBox = New TextBox
        myButton.Location = New Point(72, 160)
        myButton.Size = New Size(152, 32)
        myButton.TabIndex = 1
        myButton.Text = "Add items in list box"
        AddHandler myButton.Click, AddressOf Button_Click
        myListBox.Location = New Point(48, 32)
        myTextBox.Location = New Point(350, 32)
        myListBox.Name = "myListBox"
        myListBox.Size = New Size(200, 95)
        myTextBox.Size = myListBox.Size
        myTextBox.Multiline = True
        myListBox.TabIndex = 2
        ClientSize = New Size(700, 300)
        Controls.AddRange(New Control() {myListBox, myButton, myTextBox})
        Text = " 'Control_Invoke' example "
        myDelegate = New AddListItem(AddressOf AddListItemMethod)
        myMessageDelegate = New MessageDelegate(AddressOf MyDialog)
    End Sub 'New
 
    Shared Sub Main()
        Dim myForm As New MyFormControl()
        myForm.ShowDialog()
    End Sub 'Main
 
    Public Sub AddListItemMethod(ByVal myString As String)
        myListBox.Items.Add(myString)
    End Sub 'AddListItemMethod
 
    Private Function MyDialog(ByVal message As String) As Boolean
        If MsgBox(message, MsgBoxStyle.OkCancel, "Hintergrund") = _
          MsgBoxResult.Cancel Then
            Return False
        Else
            Return True
        End If
    End Function
 
    Private Sub Button_Click(ByVal sender As Object, ByVal e As EventArgs)
        myThread = New Thread(New ThreadStart(AddressOf ThreadFunction))
        myThread.Start()
    End Sub 'Button_Click
 
    Private Sub ThreadFunction()
        Dim myThreadClassObject As New MyThreadClass(Me)
        myThreadClassObject.Run()
    End Sub 'ThreadFunction
 
 
    Private Sub InitializeComponent()
        Me.components = New System.ComponentModel.Container
        Dim resources As System.ComponentModel.ComponentResourceManager = New _
          System.ComponentModel.ComponentResourceManager(GetType(MyFormControl))
        Me.SuspendLayout()
        '
        '
        'MyFormControl
        '
        Me.ClientSize = New System.Drawing.Size(694, 700)
        Me.Name = "MyFormControl"
        Me.ResumeLayout(False)
        Me.PerformLayout()
 
    End Sub
 
    Friend WithEvents TextBox1 As System.Windows.Forms.TextBox
    Friend WithEvents textbox2 As System.Windows.Forms.TextBox
 
 
    Private Sub MyFormControl_Load(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles MyBase.Load
 
 
    End Sub
 
    Private components As System.ComponentModel.IContainer
End Class 'MyFormControl
 
 
Public Class MyThreadClass
    Private myFormControl1 As MyFormControl
 
    Public Sub New(ByVal myForm As MyFormControl)
        myFormControl1 = myForm
 
    End Sub 'New
 
    Private myString As String
 
    Public Sub Run()
 
        Dim i As Integer
        For i = 1 To 10
            myString = "Step number " + i.ToString() + " executed"
            Thread.Sleep(400)
            ' Execute the specified delegate on the thread that owns
            ' 'myFormControl1' control's underlying window handle with
            ' the specified list of arguments.
            myFormControl1.Invoke(myFormControl1.myDelegate, New Object() _
              {myString})
 
            If i = 5 Then
                Dim r As Boolean = _
                CType(myFormControl1.Invoke(myFormControl1.myMessageDelegate, _
                New Object() {"Weitermachen?"}), Boolean)
                If r = False Then Exit For
            End If
        Next i
    End Sub 'Run
End Class 'MyThreadClass