用VB捕捉屏幕图象

声明：
　　PrivateDeclareFunctionReleaseDCLib"user32"(ByValhwndAsLong,ByValhdcAsLong)AsLong
　　PrivateDeclareFunctionOpenClipboardLib"user32"(ByValhwndAsLong)AsLong
　　PrivateDeclareFunctionEmptyClipboardLib"user32"()AsLong
　　PrivateDeclareFunctionSetClipboardDataLib"user32"(ByValwFormatAsLong,ByValhMemAsLong)AsLong
　　PrivateDeclareFunctionSelectObjectLib"gdi32"(ByValhdcAsLong,ByValhObjectAsLong)AsLong
　　PrivateDeclareFunctionDeleteDCLib"gdi32"(ByValhdcAsLong)AsLong
　　PrivateDeclareFunctionBitBltLib"gdi32"(ByValhDestDCAsLong,
　　ByValxAsLong,ByValyAsLong,ByValnWidthAsLong,ByValnHeightAsLong,ByValhSrcDCAsLong,ByValxSrcAsLong,ByValySrcAsLong,ByValdwRopAsLong)AsLong
　　PrivateDeclareFunctionCreateDCLib"gdi32"Alias"CreateDCA"(ByVallpDriverNameAsString,ByVallpDeviceNameAsString,ByVallpOutputAsString,lpInitDataAsLong)AsLong
　　PrivateDeclareFunctionCreateCompatibleDCLib"gdi32"(ByValhdcAsLong)AsLong
　　PrivateDeclareFunctionCreateCompatibleBitmapLib"gdi32"(ByValhdcAsLong,ByValnWidthAsLong,ByValnHeightAsLong)AsLong
　　PrivateDeclareFunctionCloseClipboardLib"user32"()AsLong
　　函数：
　　SubScrnCap(Lt,Top,Rt,Bot)
　　rWidth=Rt-Lt
　　rHeight=Bot-Top
　　SourceDC=CreateDC("DISPLAY",0,0,0)
　　DestDC=CreateCompatibleDC(SourceDC)
　　BHandle=CreateCompatibleBitmap(SourceDC,rWidth,rHeight)
　　SelectObjectDestDC,BHandle
　　BitBltDestDC,0,0,rWidth,rHeight,SourceDC,Lt,Top,&HCC0020
　　Wnd=Screen.ActiveForm.hwnd
　　OpenClipboardWnd
　　EmptyClipboard
　　SetClipboardData2,BHandle
　　CloseClipboard
　　DeleteDCDestDC
　　ReleaseDCDHandle,SourceDC
　　EndSub
　　以下的示例把屏幕图象捕捉后，放到Picture1中。
　　SubCommand1_Click()
　　Form1.Visible=False
　　ScrnCap0,0,640,480
　　Form1.Visible=True
　　picture1=Clipboard.GetData()
　　EndSub->