我们在
编程中，为了达到特殊的要求，有时需要屏蔽功能CTRL+ALT+DLE，本示例
程序将教你如何实现它。
实现步骤：
1．建立一个新项目，将其命名为DEMO3.vbp。
2．在Form1窗体的声明中加入以下代码：
Private Declare Function SystemParametersInfo Lib "user32" Alias "SystemParametersInfoA" (ByVal uAction As Long, ByVal uParam As Long, ByRef lpvParam As Any, ByVal fuWinIni As Long) As Long
Const SPI_SCREENSAVERRUNNING = 97
3． 在Form1窗口的Command1_Click中加入以下代码：
Private Sub Command1_Click()
Dim r As Integer
Dim p As Boolean
If Command1.Caption = "屏蔽" Then
r = SystemParametersInfo(SPI_SCREENSAVERRUNNING, True, p, 0)
Command1.Caption = "有效"
Else
r = SystemParametersInfo(SPI_SCREENSAVERRUNNING, False, p, 0)
Command1.Caption = "屏蔽"
End If
End Sub
4． 在Form1窗体的Form_Unload中加入以下代码：
Form1_Unload()
Dim r As Integer
Dim p As Boolean
r = SystemParametersInfo(SPI_SCREENSAVERRUNNING, False, p, 0)
