[求助]滚动条闪烁如何解决?急盼!
下面一段是VB支持鼠标滚轮程序代码,现在的问题是:滚动条会闪烁,怎样消除?请高手指点,急盼!
模块:
Option Explicit
Public Type POINTL
x As Long
y As Long
End Type
Declare Function CallWindowProc _
Lib "USER32" Alias "CallWindowProcA" _
(ByVal lpPrevWndFunc As Long, _
ByVal hWnd As Long, _
ByVal Msg As Long, _
ByVal wParam As Long, _
ByVal lParam As Long) As Long
Declare Function SetWindowLong _
Lib "USER32" Alias "SetWindowLongA" _
(ByVal hWnd As Long, _
ByVal nIndex As Long, _
ByVal dwNewLong As Long) As Long
Declare Function SystemParametersInfo _
Lib "USER32" Alias "SystemParametersInfoA" _
(ByVal uAction As Long, _
ByVal uParam As Long, _
lpvParam As Any, _
ByVal fuWinIni As Long) As Long
Declare Function ScreenToClient Lib "USER32" _
(ByVal hWnd As Long, xyPoint As POINTL) As Long
Public Const GWL_WNDPROC = -4
Public Const SPI_GETWHEELSCROLLLINES = 104
Public Const WM_MOUSEWHEEL = &H20A
Public WHEEL_SCROLL_LINES As Long
Global lpPrevWndProc As Long
Public Sub Hook(ByVal hWnd As Long)
lpPrevWndProc = SetWindowLong(hWnd, GWL_WNDPROC, AddressOf WindowProc)
Call SystemParametersInfo(SPI_GETWHEELSCROLLLINES, 0, WHEEL_SCROLL_LINES, 0)
If WHEEL_SCROLL_LINES > Form1.VScroll1.Max Then
WHEEL_SCROLL_LINES = Form1.VScroll1.Max
End If
End Sub
Public Sub UnHook(ByVal hWnd As Long)
Dim lngReturnValue As Long
lngReturnValue = SetWindowLong(hWnd, GWL_WNDPROC, lpPrevWndProc)
End Sub
Function WindowProc(ByVal hw As Long, _
ByVal uMsg As Long, _
ByVal wParam As Long, _
ByVal lParam As Long) As Long
Dim pt As POINTL
Select Case uMsg
Case WM_MOUSEWHEEL
If wParam = -7864320 Then
If Form1.VScroll1.Value <= Form1.VScroll1.Max - 10 Then
Form1.VScroll1.Value = Form1.VScroll1.Value + 10
Else
Form1.VScroll1.Value = Form1.VScroll1.Max
End If
ElseIf wParam = 7864320 Then
If Form1.VScroll1.Value >= 10 Then
Form1.VScroll1.Value = Form1.VScroll1.Value - 10
Else
Form1.VScroll1.Value = 0
End If
End If
Case Else
WindowProc = CallWindowProc(lpPrevWndProc, hw, uMsg, wParam, lParam)
End Select
End Function
Public Function HIWORD(LongIn As Long) As Integer
HIWORD = (LongIn And &HFFFF0000) \ &H10000
End Function
Public Function LOWORD(LongIn As Long) As Integer
LOWORD = LongIn And &HFFFF&
End Function
程序:
Private Sub Form_Load()
Hook Me.hWnd
End Sub
Private Sub Form_Resize()
If Frame1.Height > Me.Height Then
VScroll1.Visible = True
Else
VScroll1.Visible = False
End If
If Frame1.Width > Me.Width Then
HScroll1.Visible = True
Else
HScroll1.Visible = False
End If
HScroll1.Left = 0
HScroll1.Top = Me.ScaleHeight - HScroll1.Height
VScroll1.Left = Me.ScaleWidth - VScroll1.Width
VScroll1.Top = 0
HScroll1.Width = Me.ScaleWidth
VScroll1.Height = Me.ScaleHeight
If VScroll1.Visible = True Then
If HScroll1.Visible = True Then
HScroll1.Width = Abs(Me.ScaleWidth - VScroll1.Width)
VScroll1.Height = Abs(Me.ScaleHeight - HScroll1.Height)
End If
End If
HScroll1.Max = (Frame1.Width - Me.Width) + 3 * VScroll1.Width
VScroll1.Max = (Frame1.Height - Me.Height) + 3 * HScroll1.Height
HScroll1.ZOrder
VScroll1.ZOrder
End Sub
Private Sub Form_Unload(Cancel As Integer)
UnHook Me.hWnd
End Sub
Private Sub HScroll1_Change()
Frame1.Left = -HScroll1.Value
End Sub
Private Sub VScroll1_Change()
Frame1.Top = -VScroll1.Value
End Sub