动态改变屏幕设置


我们经常看到许多 Win95 的应用程序（尤其是游戏）在运行它的时候改变屏幕的设置，运行完后恢复，在 VB 中，我们可以用以下方法实现：
　
定义
Private Declare Function lstrcpy _
Lib "kernel32" Alias "lstrcpyA" _
(lpString1 As Any, lpString2 As Any) _
As Long
Const CCHDEVICENAME = 32
Const CCHFORMNAME = 32
Private Type DEVMODE
dmDeviceName As String * CCHDEVICENAME
dmSpecVersion As Integer
dmDriverVersion As Integer
dmSize As Integer
dmDriverExtra As Integer
dmFields As Long
dmOrientation As Integer
dmPaperSize As Integer
dmPaperLength As Integer
dmPaperWidth As Integer
dmScale As Integer
dmCopies As Integer
dmDefaultSource As Integer
dmPrintQuality As Integer
dmColor As Integer
dmDuplex As Integer
dmYResolution As Integer
dmTTOption As Integer
dmCollate As Integer
dmFormName As String * CCHFORMNAME
dmUnusedPadding As Integer
dmBitsPerPel As Integer
dmPelsWidth As Long
dmPelsHeight As Long
dmDisplayFlags As Long
dmDisplayFrequency As Long
End Type
Private Declare Function _
ChangeDisplaySettings Lib _
"User32" Alias "ChangeDisplaySettingsA" (_
ByVal lpDevMode As Long, _
ByVal dwflags As Long) As Long
　
函数
Public Function SetDisplayMode(Width As _
Integer,Height As Integer, Color As _
Integer) As Long
Const DM_PELSWIDTH = &H80000
Const DM_PELSHEIGHT = &H100000
Const DM_BITSPERPEL = &H40000
Dim NewDevMode As DEVMODE
Dim pDevmode As Long
With NewDevMode
.dmSize = 122
If Color = -1 Then
.dmFields = DM_PELSWIDTH Or DM_PELSHEIGHT
Else
.dmFields = DM_PELSWIDTH Or _
DM_PELSHEIGHT Or DM_BITSPERPEL
End If
.dmPelsWidth = Width
.dmPelsHeight = Height
　
If Color <> -1 Then
.dmBitsPerPel = Color
End If
End With
pDevmode = lstrcpy(NewDevMode, NewDevMode)
SetDisplayMode = ChangeDisplaySettings(pDevmode, 0)
End Function
　
例子调用：改变为 640x480x24位：
i = SetDisplayMode(640, 480, 24)
如果成功返回 0 。

在VB中显示动画鼠标图标
Win95 的动画鼠标为应用程序增色不少，而 VB 则只提供一般的鼠标图标支持。要用 VB 显示动画鼠标形状，你可以使用以下方法：
函数声明：
Public Const GCL_HCURSOR = -12
　
Declare Function ClipCursor Lib "user32" (lpRect As Any) As Long
Declare Function DestroyCursor Lib "user32" (ByVal hCursor As Any) As Long
Declare Function LoadCursorFromFile Lib "user32" Alias "LoadCursorFromFileA" (ByVal
lpFileName As String) As Long
Declare Function SetClassLong Lib "user32" Alias "SetClassLongA" (ByVal hwnd As Long,
ByVal nIndex As Long, ByVal dwNewLong As Long) As Long
Declare Function GetClassLong Lib "user32" Alias "GetClassLongA" (ByVal hwnd As Long,
ByVal nIndex As Long) As Long
使用：
　
Dim mhBaseCursor As Long, mhAniCursor As Long
Dim lResult As Long
mhAniCursor = LoadCursorFromFile("c:\windows\cursors\appstart.ani")
lResult = SetClassLong((hwnd), GCL_HCURSOR, mhAniCursor)