有一个类似的问题 https://stackoverflow.com/questions/4176340关于如何使用 C# 实现这一点。注意这个答案 https://stackoverflow.com/a/4176361/22114，它解释了为什么在某些情况下它可能根本不可能。
有关如何捕获屏幕截图的一些 VB 示例代码，请参见本文 http://support.microsoft.com/kb/161299来自微软。以下是最相关的部分：
Option Explicit
Option Base 0
Private Type PALETTEENTRY
peRed As Byte
peGreen As Byte
peBlue As Byte
peFlags As Byte
End Type
Private Type LOGPALETTE
palVersion As Integer
palNumEntries As Integer
palPalEntry(255) As PALETTEENTRY ' Enough for 256 colors.
End Type
Private Type GUID
Data1 As Long
Data2 As Integer
Data3 As Integer
Data4(7) As Byte
End Type
Private Const RASTERCAPS As Long = 38
Private Const RC_PALETTE As Long = &H100
Private Const SIZEPALETTE As Long = 104
Private Type RECT
Left As Long
Top As Long
Right As Long
Bottom As Long
End Type
Private Declare Function CreateCompatibleDC Lib "GDI32" (ByVal hDC As Long) As Long
Private Declare Function CreateCompatibleBitmap Lib "GDI32" ( _
ByVal hDC As Long, _
ByVal nWidth As Long, _
ByVal nHeight As Long) As Long
Private Declare Function GetDeviceCaps Lib "GDI32" (ByVal hDC As Long, ByVal iCapabilitiy As Long) As Long
Private Declare Function GetSystemPaletteEntries Lib "GDI32" ( _
ByVal hDC As Long, _
ByVal wStartIndex As Long, _
ByVal wNumEntries As Long, _
lpPaletteEntries As PALETTEENTRY) As Long
Private Declare Function CreatePalette Lib "GDI32" (lpLogPalette As LOGPALETTE) As Long
Private Declare Function SelectObject Lib "GDI32" (ByVal hDC As Long, ByVal hObject As Long) As Long
Private Declare Function BitBlt Lib "GDI32" ( _
ByVal hDCDest As Long, _
ByVal XDest As Long, _
ByVal YDest As Long, _
ByVal nWidth As Long, _
ByVal nHeight As Long, _
ByVal hDCSrc As Long, _
ByVal XSrc As Long, _
ByVal YSrc As Long, _
ByVal dwRop As Long) As Long
Private Declare Function DeleteDC Lib "GDI32" (ByVal hDC As Long) As Long
Private Declare Function GetForegroundWindow Lib "USER32" () As Long
Private Declare Function SelectPalette Lib "GDI32" ( _
ByVal hDC As Long, _
ByVal hPalette As Long, _
ByVal bForceBackground As Long) As Long
Private Declare Function RealizePalette Lib "GDI32" (ByVal hDC As Long) As Long
Private Declare Function GetWindowDC Lib "USER32" (ByVal hWnd As Long) As Long
Private Declare Function GetDC Lib "USER32" (ByVal hWnd As Long) As Long
Private Declare Function GetWindowRect Lib "USER32" (ByVal hWnd As Long, lpRect As RECT) As Long
Private Declare Function ReleaseDC Lib "USER32" (ByVal hWnd As Long, ByVal hDC As Long) As Long
Private Declare Function GetDesktopWindow Lib "USER32" () As Long
Private Type PicBmp
Size As Long
Type As Long
hBmp As Long
hPal As Long
Reserved As Long
End Type
Private Declare Function OleCreatePictureIndirect Lib "olepro32.dll" ( _
PicDesc As PicBmp, _
RefIID As GUID, _
ByVal fPictureOwnsHandle As Long, _
IPic As IPicture) As Long
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
'
' CreateBitmapPicture
' - Creates a bitmap type Picture object from a bitmap and
' palette.
'
' hBmp
' - Handle to a bitmap.
'
' hPal
' - Handle to a Palette.
' - Can be null if the bitmap doesn't use a palette.
'
' Returns
' - Returns a Picture object containing the bitmap.
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
Public Function CreateBitmapPicture(ByVal hBmp As Long, ByVal hPal As Long) As Picture
Dim r As Long
Dim Pic As PicBmp
' IPicture requires a reference to "Standard OLE Types."
Dim IPic As IPicture
Dim IID_IDispatch As GUID
' Fill in with IDispatch Interface ID.
With IID_IDispatch
.Data1 = &H20400
.Data4(0) = &HC0
.Data4(7) = &H46
End With
' Fill Pic with necessary parts.
With Pic
.Size = Len(Pic) ' Length of structure.
.Type = vbPicTypeBitmap ' Type of Picture (bitmap).
.hBmp = hBmp ' Handle to bitmap.
.hPal = hPal ' Handle to palette (may be null).
End With
' Create Picture object.
r = OleCreatePictureIndirect(Pic, IID_IDispatch, 1, IPic)
' Return the new Picture object.
Set CreateBitmapPicture = IPic
End Function
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
'
' CaptureWindow
' - Captures any portion of a window.
'
' hWndSrc
' - Handle to the window to be captured.
'
' LeftSrc, TopSrc, WidthSrc, HeightSrc
' - Specify the portion of the window to capture.
' - Dimensions need to be specified in pixels.
'
' Returns
' - Returns a Picture object containing a bitmap of the specified
' portion of the window that was captured.
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
Public Function CaptureWindow( _
ByVal hWndSrc As Long, _
ByVal LeftSrc As Long, _
ByVal TopSrc As Long, _
ByVal WidthSrc As Long, _
ByVal HeightSrc As Long) As Picture
Dim hDCMemory As Long
Dim hBmp As Long
Dim hBmpPrev As Long
Dim r As Long
Dim hDCSrc As Long
Dim hPal As Long
Dim hPalPrev As Long
Dim RasterCapsScrn As Long
Dim HasPaletteScrn As Long
Dim PaletteSizeScrn As Long
Dim LogPal As LOGPALETTE
' Get device context for entire window.
hDCSrc = GetWindowDC(hWndSrc)
' Create a memory device context for the copy process.
hDCMemory = CreateCompatibleDC(hDCSrc)
' Create a bitmap and place it in the memory DC.
hBmp = CreateCompatibleBitmap(hDCSrc, WidthSrc, HeightSrc)
hBmpPrev = SelectObject(hDCMemory, hBmp)
' Get screen properties.
RasterCapsScrn = GetDeviceCaps(hDCSrc, RASTERCAPS) ' Raster
' capabilities.
HasPaletteScrn = RasterCapsScrn And RC_PALETTE ' Palette
' support.
PaletteSizeScrn = GetDeviceCaps(hDCSrc, SIZEPALETTE) ' Size of
' palette.
' If the screen has a palette make a copy and realize it.
If HasPaletteScrn And (PaletteSizeScrn = 256) Then
' Create a copy of the system palette.
LogPal.palVersion = &H300
LogPal.palNumEntries = 256
r = GetSystemPaletteEntries(hDCSrc, 0, 256, _
LogPal.palPalEntry(0))
hPal = CreatePalette(LogPal)
' Select the new palette into the memory DC and realize it.
hPalPrev = SelectPalette(hDCMemory, hPal, 0)
r = RealizePalette(hDCMemory)
End If
' Copy the on-screen image into the memory DC.
r = BitBlt(hDCMemory, 0, 0, WidthSrc, HeightSrc, hDCSrc, LeftSrc, TopSrc, vbSrcCopy)
' Remove the new copy of the on-screen image.
hBmp = SelectObject(hDCMemory, hBmpPrev)
' If the screen has a palette get back the palette that was
' selected in previously.
If HasPaletteScrn And (PaletteSizeScrn = 256) Then
hPal = SelectPalette(hDCMemory, hPalPrev, 0)
End If
' Release the device context resources back to the system.
r = DeleteDC(hDCMemory)
r = ReleaseDC(hWndSrc, hDCSrc)
' Call CreateBitmapPicture to create a picture object from the
' bitmap and palette handles. Then return the resulting picture
' object.
Set CaptureWindow = CreateBitmapPicture(hBmp, hPal)
End Function
