拖动无标题窗口

     通常我们是拖动标题栏来移动窗口，当没有标题栏时，该如何来拖动窗口呢？方法是 当我们在窗口区按下鼠标左键时，调用ReleaseCapture函数，释放鼠标的俘获，同时 发送移动标题栏的消息，就可以实现窗口的拖动。
下面的例子实现了该功能。
>>步骤1----建立新工程，在窗体上放置CommandButton按钮。
>>步骤2----改变窗体的外观，使BorderStyle = 0(None)
>>步骤3----编写如下代码：

Private Declare Function ReleaseCapture Lib "user32" () As Long
Private Declare Function SendMessage Lib "user32" Alias _
    "SendMessageA" (ByVal hwnd As Long, ByVal _
    wMsg As Long, ByVal wParam As Long, _
    lParam As Any) As Long

Private Const WM_SYSCOMMAND = &H112
Private Const SC_MOVE = &HF010&
Private Const WM_NCLBUTTONDOWN = &HA1
Private Const HTCAPTION = 2

Private Sub Command1_Click()
    End
End Sub

Private Sub Form_MouseDown(Button As Integer, Shift As Integer, X As Single, Y As Single)
    ReleaseCapture
    SendMessage Me.hwnd, WM_SYSCOMMAND, SC_MOVE + HTCAPTION, 0
    ''SendMessage hwnd, WM_NCLBUTTONDOWN, HTCAPTION, 0&
    ''上述两种方法都能实现该功能。
End Sub

>>步骤4----编译运行，在窗体上按下鼠标左键，是不是可以拖动了？按下Command1结束。