خودم یه نمونه پیدا کردم
در ضمن منظورم همون Me.TransparencyKey=Me.BackColor در windows form هستش که میاد گوشه های خالی عکس رو برمی داره تو عکسها رنگ صورتی هستش
http://social.msdn.microsoft.com/For...b-073dd6fc177c
transparent a wpf UserControl in a win application
Imports System.Runtime.InteropServices
Public Class Form1
Public Const SRCCOPY As Integer = &HCC0020
<DllImport("user32.dll")> _
Public Shared Function GetWindowDC(hWnd As IntPtr) As IntPtr
End Function
<DllImport("gdi32.dll")> _
Public Shared Function BitBlt(hObject As IntPtr, nXDest As Integer, nYDest As Integer, nWidth As Integer, nHeight As Integer, hObjectSource As IntPtr, _
nXSrc As Integer, nYSrc As Integer, dwRop As Integer) As Boolean
End Function
<DllImport("gdi32.dll")> _
Public Shared Function CreateCompatibleDC(hDC As IntPtr) As IntPtr
End Function
<DllImport("user32.dll")> _
Public Shared Function GetDesktopWindow() As IntPtr
End Function
<System.Runtime.InteropServices.DllImport("gdi32.d ll")> _
Public Shared Function DeleteObject(hObject As IntPtr) As Boolean
End Function
Private Sub Form_Des_load(sender As Object, e As System.EventArgs) Handles Me.Load
ElementHost1.BackgroundImage = CaptureWindow(GetDesktopWindow())
End Sub
'**************************Capture Window ****************************
Public Function CaptureWindow(handle As IntPtr) As Bitmap
Dim bitmaps As New Bitmap(Me.Width, Me.Height)
Dim g As Graphics = Graphics.FromImage(bitmaps)
Dim bmDC As System.IntPtr = g.GetHdc()
Dim hdcSrc As IntPtr = GetWindowDC(handle)
BitBlt(bmDC, 0, 0, Me.Width, Me.Height, hdcSrc, _
Me.Left, Me.Top, SRCCOPY)
g.Dispose()
Return bitmaps
End Function
End Class