Intercepting computer screens with C #

Today boring turn code, turn out a previously written C # screenshot function ... Take it out and share it with everyone.
This code is written in reference to a section of the screen in C + + code rewrite. It's just a statement of the API.
The declared APIs are also appended. For reference. If there are any questions, please note.
Author: appledotnet

///
Intercepting part of the screen
///
Upper left corner
Lower right corner
is full screen
return value bitmap
public static Bitmap Getpartscreen (point p1,point p2,bool Full)
{
IntPtr HSCRDC,HMEMDC;
IntPtr Hbitmap,holdbitmap;
int nx,ny,nx2,ny2;
nx=ny=nx2=ny2=0;
int nwidth, nheight;
int XSCRN, YSCRN;
HSCRDC = CreateDC ("DISPLAY", NULL, NULL, 0);//create DC handle
HMEMDC = CreateCompatibleDC (HSCRDC);//Create a memory DC
XSCRN = GetDeviceCaps (HSCRDC, getdevicecapsindex.horzres);//Get screen width
YSCRN = GetDeviceCaps (HSCRDC, getdevicecapsindex.vertres);//Get screen height
if (full)//If the entire screen is intercepted
{
NX = 0;
NY = 0;
NX2 = XSCRN;
Ny2 = YSCRN;
}
Else
{
NX = P1. X
NY = P1. Y
Nx2 =P2. X
Ny2 =P2. Y
Check numerical validity
if (nx<0) NX = 0;
if (ny<0) NY = 0;
if (NX2&GT;XSCRN) nx2 = XSCRN;
if (NY2&GT;YSCRN) Ny2 = YSCRN;
}
nwidth = width of nx2-nx;//intercept range
nheight = height of ny2-ny;//intercept range
Hbitmap = CreateCompatibleBitmap (HSCRDC, nwidth, nheight);//Copy from memory DC to HBITMAP handle
Holdbitmap = SelectObject (HMEMDC, HBITMAP);
BitBlt (HMEMDC, 0, 0, nwidth, NHEIGHT,HSCRDC, NX, NY, (UInt32) 0xcc0020);
Hbitmap = SelectObject (HMEMDC, Holdbitmap);
DeleteDC (HSCRDC);//Delete used objects
DeleteDC (HMEMDC);//Delete used objects
Return Bitmap.fromhbitmap (HBITMAP)//Bitmap.fromhbitmap from Hbitmap to Bitmap
}

The API declaration used:

 [dllimport ("Gdi32.dll")]
public static extern IntPtr CreateDC (
 string lpszdriver,        //driver name
 string lpszdevice,        //Device name
 string lpszoutput,       //not used; should Be NULL
 int64 lpinitdata //optional printer data
 ;
&NBSP
[DllImport ("Gdi32.dll")]
public static extern IntPtr CreateCompatibleDC (
 intptr HDC//Handle to DC
 );
 
[DllImport ("Gdi32.dll")]
public static extern int GetDeviceCaps (
 intptr hdc,     //Handle to DC
 getdevicecapsindex nindex  //index of Capability
);

[DllImport ("Gdi32.dll")]
public static extern IntPtr CreateCompatibleBitmap (
INTPTR hdc,//Handle to DC
int nwidth,//width of bitmap, in pixels
int nheight//height of bitmap, in pixels
);

[DllImport ("Gdi32.dll")]
public static extern IntPtr SelectObject (
INTPTR hdc,//Handle to DC
INTPTR hgdiobj//Handle to Object
);

[DllImport ("Gdi32.dll")]
public static extern int BitBlt (
IntPtr hdcdest,//handle to destination DC
int nxdest,//X-coord of destination Upper-left corner
int nydest,//Y-coord of destination Upper-left corner
int nwidth,//width of destination Rectangle
int nheight,//height of destination Rectangle
IntPtr hdcsrc,//handle to source DC
int NXSRC,//x-coordinate of source Upper-left Corner
int NYSRC,//y-coordinate of source Upper-left Corner
UInt32 dwrop//Raster operation code
);

[DllImport ("Gdi32.dll")]
public static extern int DeleteDC (
INTPTR HDC//Handle to DC
);