Visual Basic

Dim newForm As New MyForm 'Initilize will be called here
newForm.MyProperty = "Something"
newForm.Show

Module EnumWindows
    Delegate Function EnumWindows_Callback(ByVal hWnd As Integer, ByVal lParam As Integer) As Integer


    Public Declare Function EnumWindows Lib "user32" _
        (ByVal lpEnumFunc As EnumWindows_Callback, _
            ByVal lParam As Integer) As Integer

    Public Declare Function EnumChildWindows Lib "user32" _
        (ByVal hWndParent As Integer, ByVal lpEnumFunc As EnumWindows_Callback, _
            ByVal lParam As Integer) As Integer

    Public Declare Function GetClassName Lib "user32" Alias "GetClassNameA" _
        (ByVal hWnd As Integer, ByVal lpClassName As System.Text.StringBuilder, _
            ByVal nMaxCount As Integer) As Integer

    Public Declare Function GetWindowText Lib "user32" Alias "GetWindowTextA" _
        (ByVal hWnd As Integer, ByVal lpString As System.Text.StringBuilder, _
            ByVal cch As Integer) As Integer

    ' The callback routine, common to both EnumWindows and EnumChildWindows.
    ' the argument passed in lParam is the indent level.

    Function EnumWindows_CBK(ByVal hWnd As Integer, ByVal lParam As Integer) As Integer
        ' display information on this window, with correct indentation
        Console.WriteLine(New String(" "c, lParam * 3) & WindowDescription(hWnd))
        ' then display all child windows, but indent them to the right
        EnumChildWindows(hWnd, AddressOf EnumWindows_CBK, lParam + 1)
        ' Return 1 to continue enumeration.
        Return 1
    End Function

    ' return a windows description given its hWnd

    Function WindowDescription(ByVal hWnd As Integer) As String
        Dim text As String
        text = WindowText(hWnd)

        WindowDescription = "[" & Right$("0000000" & Hex$(hWnd), 8) & "] " _
            & WindowClassName(hWnd)
        If Len(text) > 0 Then
            WindowDescription &= " - """ & text & """"
        End If
    End Function

    ' Return the caption/text of a window.

    Function WindowText(ByVal hWnd As Integer) As String
        Dim buffer As New System.Text.StringBuilder(256)
        Dim length As Integer
        length = GetWindowText(hWnd, buffer, buffer.Capacity)
        WindowText = buffer.ToString.Substring(0, length)
    End Function

    Function WindowClassName(ByVal hWnd As Integer) As String
        Dim buffer As New System.Text.StringBuilder(256)
        Dim length As Integer
        length = GetClassName(hWnd, buffer, buffer.Capacity)
        WindowClassName = buffer.ToString.Substring(0, length)
    End Function

End Module

Sub TestAPICallback()
        EnumWindows(AddressOf EnumWindows_CBK, 0)
    End Sub