用VB.Net实现屏幕捕捉(类)

系统崩溃

我想对某些朋友可能有用。
.Net Framework并不万能，还是得用上API。

Public Class ScrCap

Private Declare Function CreateDC Lib "gdi32" Alias "CreateDCA" (ByVal lpDriverName As String, ByVal lpDeviceName As String, ByVal lpOutput As String, ByVal lpInitData As Int32) As Int32
Private Declare Function BitBlt Lib "gdi32" (ByVal hDestDC As Integer, ByVal x As Integer, ByVal y As Integer, ByVal nWidth As Integer, ByVal nHeight As Integer, ByVal hSrcDC As Integer, ByVal xSrc As Integer, ByVal ySrc As Integer, ByVal dwRop As Integer) As Integer

    '将指定屏幕区域内容保存到Bitmap对象
Public Function CaptureScreenToBitmap(ByVal Left As Int32, ByVal Top As Int32, ByVal Width As Int32, ByVal Height As Int32) As Bitmap
        Dim DisplayDC As New IntPtr(CreateDC("DISPLAY", Nothing, Nothing, 0))
        Dim G1 As Graphics = Graphics.FromHdc(DisplayDC)
        Dim Bmp As New Bitmap(Width, Height, G1)
        Dim G2 As Graphics = Graphics.FromImage(Bmp)
        Dim BmpDC As IntPtr = G2.GetHdc()
        BitBlt(BmpDC.ToInt32, 0, 0, Width, Height, DisplayDC.ToInt32, Left, Top, &HCC0020)
        G2.ReleaseHdc(BmpDC)
        DisplayDC = Nothing
        Return Bmp
End Function

End Class

jyc8778

year

xgreenclover

cool

Miu.C

API is the base.

Canbitwell

yeah, I won't use GetDIBits any longer,(it is slow processing pixcel by pixcel  , yours is fast)


BTW: why not make method CaptureScreenToBitmap a shared member , it would be better.

系统崩溃

make method CaptureScreenToBitmap a shared member？
你的意思是写成
Public Shared CaptureScreenToBitmap
是为了不生成类实例也能调用吧？

Canbitwell

yes,
以前遇到过类似情况，vs带的代码分析就建议我改成共享成员，说那样性能更高……
（估计是少占内存）