VB.net 监视Windows剪切板中数据变化

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新建一个Winform,拉进去一个PictureBox控件,完整代码如下,实现效果即当剪切板中更新图片数据的时候,picturebox中自动显示出来剪切板中的图片

Public Class clipboardMon
#Region " Definitions "
    'Constants for API Calls...
    Private Const WM_DRAWCLIPBOARD As Integer = &H308
    Private Const WM_CHANGECBCHAIN As Integer = &H30D

    'Handle for next clipboard viewer...
    Private mNextClipBoardViewerHWnd As IntPtr

    'API declarations...
    Declare Auto Function SetClipboardViewer Lib "user32" (ByVal HWnd As IntPtr) As IntPtr
    Declare Auto Function ChangeClipboardChain Lib "user32" (ByVal HWnd As IntPtr, ByVal HWndNext As IntPtr) As Boolean
    Declare Auto Function SendMessage Lib "User32" (ByVal HWnd As IntPtr, ByVal Msg As Integer, ByVal wParam As IntPtr, ByVal lParam As IntPtr) As Long
#End Region

#Region " Contructor "
    Public Sub NewViewer()
        'InitializeComponent()
        'To register this form as a clipboard viewer...
        Clipboard.Clear()
        mNextClipBoardViewerHWnd = SetClipboardViewer(Me.Handle)

    End Sub
#End Region
#Region " Message Process "
    'Override WndProc to get messages...
    Protected Overrides Sub WndProc(ByRef m As Message)
        Select Case m.Msg
            Case Is = WM_DRAWCLIPBOARD 'The clipboard has changed...
                '##########################################################################
                ' Process Clipboard Here :)........................
                '##########################################################################
                SendMessage(mNextClipBoardViewerHWnd, m.Msg, m.WParam, m.LParam)

                '显示剪贴板中的图片信息
                If Clipboard.ContainsImage() = True Then
                    PictureBox1.Image = Clipboard.GetImage()
                    PictureBox1.Update()
                End If

            Case Is = WM_CHANGECBCHAIN 'Another clipboard viewer has removed itself...
                If m.WParam = CType(mNextClipBoardViewerHWnd, IntPtr) Then
                    mNextClipBoardViewerHWnd = m.LParam
                Else
                    SendMessage(mNextClipBoardViewerHWnd, m.Msg, m.WParam, m.LParam)
                End If
        End Select

        MyBase.WndProc(m)
    End Sub
#End Region
    Private Sub clipboardMon_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        NewViewer()
    End Sub
End Class


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