这个例子演示了如何强制重画窗口某一区域.有时这是很需要的,例如当你使用LockWindowUpdate API 函数来加快某一控件的数据加载速度时.
新建一个工程,添加一个模块,代码如下:
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
在窗体上放置一个按钮和列表框.使列表框足够大以便观察效果.然后添加以下代码:
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
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