Capture screen with C #

Using system;
Using system. Windows. forms;
Using system. drawing;
Using system. Drawing. imaging;
Using system. runtime. interopservices;

Namespace printscreen
{
// Some code comes from the network
[Structlayout (layoutkind. Sequential)]
Public struct rect
{
Public int left;
Public int top;
Public int right;
Public int bottom;
}
// Encapsulate Some APIs
Public class apitmp
{
[Dllimport ("user32.dll")]
Public static extern bool getcursorpos (ref point lppoint );
[Dllimport ("user32.dll")]
Public static extern int windowfrompoint (point lppoint );
[Dllimport ("user32.dll")]
Public static extern intptr getasktopwindow ();
[Dllimport ("user32.dll")]
Public static extern int getforegroundwindow ();
[Dllimport ("user32.dll")]
Public static extern int getwindowrect (INT hwnd, ref rect RC );
[Dllimport ("user32.dll")]
Public static extern int getwindowdc (INT hwnd );
[Dllimport ("gdi32.dll")]
Public static extern bool bitblt (
Intptr hdcdest, // handle of the target device
Int nxdest, // X coordinate in the upper left corner of the target object
Int nydest, // X coordinate in the upper left corner of the target object
Int nwidth, // The width of the rectangle of the target object
Int nheight, // The length of the rectangle of the target object
Intptr hdcsrc, // Source Device handle
Int nxsrc, // X coordinate in the upper left corner of the source object
Int nysrc, // X coordinate in the upper left corner of the source object
System. int32 dwdrop // The operation value of the grating
);
[Dllimportattribute ("gdi32.dll")]
Public static extern intptr createdc (
String lpszdriver, // driver name
String lpszdevice, // device name
String lpszoutput, // useless, can be set to "null"
Intptr lpinitdata // any printer data
);

}

// Encapsulate various screen capture operations
Public class ucapture
{
// Obtain the specified area of the screen
Public bitmap getscreen (INT left, int top, int width, int height)
{
Intptr DC1 = apitmp. createdc ("display", null, null, (intptr) null );
Graphics newgraphics = graphics. fromhdc (DC1 );
Bitmap IMG = new Bitmap (width, height, newgraphics );
Graphics thisgraphics = graphics. fromimage (IMG );
Intptr DC2 = thisgraphics. gethdc ();
Intptr DC3 = newgraphics. gethdc ();
Apitmp. bitblt (DC2, 13369376, width, height, DC3, left, top );
Thisgraphics. releasehdc (DC2 );
Newgraphics. releasehdc (DC3 );
Return IMG;
}
// Obtain the entire Screen
Public bitmap getfullscreen ()
{
Return getscreen (0, 0, screen. primaryscreen. bounds. Width, screen. primaryscreen. bounds. Height );
}
// Capture the window indicated by the handle
Public bitmap getscreenfromhandle (INT hwnd)
{
Rect rc = new rect ();
Apitmp. getwindowrect (hwnd, ref RC );
Return getscreen (RC. Left, RC. Top, RC. right-rc.left, RC. bottom-rc.top );
}
// Capture the activity window
Public bitmap getscreenfromactivewindow ()
{
Int handle = apitmp. getforegroundwindow ();
Return getscreenfromhandle (handle );
}
// Save to various formats
Public String savepic (bitmap BMP)
{
Savefiledialog savedialog = new savefiledialog ();
Savedialog. filter = "bitmap file (*. BMP) | *. BMP | JPG file (*. JPG) | *. JPG | GIF file (*. GIF) | *. GIF | TIFF File (*. tiff) | *. tiff | "+
"EMF file (*. EMF) | *. EMF | icon file (*. ICO) | *. ICO | WMF file (*. WMF) | *. WMF | PNG file (*. PNG) | *. PNG ";
Savedialog. defaultext = "*. BMP ";
If (savedialog. showdialog () = dialogresult. OK)
{
String ext = savedialog. filename. substring (savedialog. filename. Length-4, 4 );
Switch (EXT)
{
Case ". BMP ":
BMP. Save (savedialog. filename, imageformat. BMP );
Break;
Case ". GIF ":
BMP. Save (savedialog. filename, imageformat. GIF );
Break;
Case ". jpg ":
BMP. Save (savedialog. filename, imageformat. JPEG );
Break;
Case ". EMF ":
BMP. Save (savedialog. filename, imageformat. EMF );
Break;
Case ". ICO ":
BMP. Save (savedialog. filename, imageformat. Icon );
Break;
Case ". WMF ":
BMP. Save (savedialog. filename, imageformat. WMF );
Break;
Case ". PNG ":
BMP. Save (savedialog. filename, imageformat. PNG );
Break;
Case ". Tiff ":
BMP. Save (savedialog. filename, imageformat. Tiff );
Break;
Default:
Return "";
}
Return savedialog. filename;
}
Return "";
}
}
}