vb實現強制重畫窗口某一區域

這個例子演示了如何強制重畫窗口某一區域.有時這是很需要的,例如當你使用LockWindowUpdate API 函數來加快某一控件的數據加載速度時.

新建一個工程,添加一個模塊,代碼如下:

Private Type RECT
　 Left As Long
　 Top As Long
　 Right As Long
　 Bottom As Long
End Type
Private Type POINTAPI
　 X As Long
　 Y As Long
End Type
Private Declare Function GetWindowRect Lib "user32" (ByVal hWnd As Long, lpRect As RECT) As Long
Private Declare Function GetClientRect Lib "user32" (ByVal hWnd As Long, lpRect As RECT) As Long
Private Declare Function InvalidateRect Lib "user32" (ByVal hWnd As Long, lpRect As RECT, ByVal bErase As Long) As Long
Private Declare Function ScreenToClient Lib "user32" (ByVal hWnd As Long, lpPoint As POINTAPI) As Long
Public Sub RepaintWindow( ByRef objThis As Object, Optional ByVal bClientAreaOnly As Boolean = True )
　 Dim tR As RECT
　 Dim tP As POINTAPI
　 If (bClientAreaOnly) Then
　　　 GetClientRect objThis.hWnd, tR
　 Else
　　　 GetWindowRect objThis.hWnd, tR
　　　 tP.X = tR.Left: tP.Y = tR.Top
　　　 ScreenToClient objThis.hWnd, tP
　　　 tR.Left = tP.X: tR.Top = tP.Y
　　　 tP.X = tR.Right: tP.Y = tR.Bottom
　　　 ScreenToClient objThis.hWnd,
　　　 tP tR.Right = tP.X: tR.Bottom = tP.Y
　 End If
　 InvalidateRect objThis.hWnd, tR, 1
End Sub
　　 在窗體上放置一個按鈕和列表框.使列表框足夠大以便觀察效果.然後添加以下代碼:
Private Sub Command1_Click()
　 RepaintWindow List1
End Sub
Private Sub Form_Load()
　 Dim i As Long
　 For i = 1 To 200
　　 List1.AddItem "TestItem " & i
　 Next i
End Sub