Visual Basic

Public Class Test
    Private _id As Long
    Private _idSet As Boolean = False
    
    Public Property ID As Long
        Get
            Return _id
        End Get
        Set(ByVal Value As Long)
            _id = Value
            _idSet = True
        End Set
    End Property
    
    Public Sub Save()
        If _idSet Then
            'Save Data
        Else
            'Throw exception
        End If
    End Sub
End Class

'API Declarations (.NET)
Private Declare Ansi Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hWnd As IntPtr, ByVal wMsg As Integer, ByVal wParam As Integer, ByVal lParam As Integer) As Integer
'Routine to Lock a Window from Repainting
Public Sub LockWindowUpdate(ByVal Handle As IntPtr, ByVal Lock As Boolean)
	Const WM_SETREDRAW As Integer = &HB

	'Enable / Disable Drawing
	Call SendMessage(Handle, WM_SETREDRAW, Math.Abs(CInt(Lock)), 0)
End Sub

'API Declarations (VB6)
Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hWnd As Long, ByVal wMsg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
'Routine to Lock a Window from Repainting
Public Sub LockWindowUpdate(ByVal Handle As Long, ByVal Lock As Boolean)
	Const WM_SETREDRAW As Long = &HB

	'Enable / Disable Drawing
	Call SendMessage(Handle, WM_SETREDRAW, Abs(CInt(Lock)), 0)
End Sub

Private Sub ComboBox1_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles ComboBox1.SelectedIndexChanged
    Me.Refresh()
End Sub

e.Graphics.FillRectangle(Color.White, Rect)

Dim WshShell : Set WshShell = WScript.CreateObject("WScript.Shell")
Dim MyPath : MyPath = WshShell.CurrentDirectory
Dim intDoIt : intDoIt = MsgBox(MyPath)
WshShell.RegWrite "HKLM\SOFTWARE\Company\Product\InstallDir", MyPath