XP系統下顯示窗體陰影

c#代碼的出處: http://davidkean.net/archive/2004/09/13/151.aspx

Imports System
Imports System.Windows.Forms
Imports System.Security
Imports System.Security.Permissions

  Private Const CS_DROPSHADOW As Integer = &H20000

    Protected Overrides ReadOnly Property CreateParams() As CreateParams
        ' SecurityPermission(SecurityAction.LinkDemand, UnmanagedCode = True)
        Get
            Dim parameters As CreateParams = MyBase.CreateParams
            If (DropShadowSupported) Then
                parameters.ClassStyle = (parameters.ClassStyle Or CS_DROPSHADOW)
            End If
            Return parameters
        End Get
    End Property
    Public ReadOnly Property DropShadowSupported() As Boolean
        Get
            Return IsWindowsXPOrAbove
        End Get
    End Property
    Public ReadOnly Property IsWindowsXPOrAbove() As Boolean
        Get
            Dim System As OperatingSystem = Environment.OSVersion
            Dim runningNT As Boolean = (System.Platform = PlatformID.Win32NT)
            Return runningNT And System.Version.CompareTo(New Version(5, 1, 0, 0)) >= 0
        End Get
    End Property