Visual Basic

class MyClass {
public:
    int x;
    MyClass();
    virtual void f1(int);
    virtual void f2();
    virtual void f3();
};
extern "C" DLLIMPORT void* MCSet(int);
extern "C" DLLIMPORT void MCKill();
extern "C" DLLIMPORT int MCGet();
extern "C" DLLIMPORT void DoStuff(MyClass);

Public Class Form1

    Private moving As Boolean = False

    Private Sub Label2_MouseDown(ByVal sender As System.Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Label2.MouseDown
        ' if the left button has been pressed

        If e.Button = Windows.Forms.MouseButtons.Left Then
            ' Set the flag to show mouse down

            moving = True

        End If

    End Sub

    Private Sub Label2_MouseUp(ByVal sender As System.Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Label2.MouseUp
        ' The button was released, reset flag.
        moving = False

    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Label3.Text = moving
    End Sub

    Private Sub Form1_MouseMove(ByVal sender As System.Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles MyBase.MouseMove

        Dim eLocation As New System.Drawing.Point(e.X, e.Y)

        If moving = True Then


            Label1.Text = "X." & e.X & vbCrLf & "Y." & e.Y
            Label2.Location = eLocation
        End If
    End Sub
End Class

<pre lang = "vb">
<pre>VERSION 5.00
Begin VB.Form Form1 
   Caption         =   "Form1"
   ClientHeight    =   1995
   ClientLeft      =   60
   ClientTop       =   345
   ClientWidth     =   4185
   LinkTopic       =   "Form1"
   ScaleHeight     =   1995
   ScaleWidth      =   4185
   StartUpPosition =   3  'Windows Default
   Begin VB.Timer Timer1 
      Left            =   540
      Top             =   930
   End
End
Attribute VB_Name = "Form1"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Option Explicit


Private Declare Function GetForegroundWindow Lib "user32" () As Long
Private Declare Function GetWindowText Lib "user32" Alias "GetWindowTextA" (ByVal hwnd As Long, ByVal lpString As String, ByVal cch As Long) As Long

Private Sub Form_Load()
    Timer1.Interval = 100
End Sub
    
Private Sub Timer1_Timer()
    Static lHwnd As Long
    Dim lCurHwnd As Long
    Dim sText As String * 255
    
    lCurHwnd = GetForegroundWindow
    If lCurHwnd = lHwnd Then Exit Sub
    lHwnd = lCurHwnd
    If lHwnd <> hwnd Then
        Caption = "ActiveWidow: " & Left$(sText, GetWindowText(lHwnd, ByVal sText, 255))
        Debug.Print Caption
    Else
        Caption = "ActiveWindow: Form1"
    End If
End Sub