WPF使用Win32进行GDI截屏笔记

1、新建项目，并为项目添加引用:

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System.Drawing

3、添加一个类，命名空间自定：

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;

namespace HJess
{
public class ScreenDevice
{
public const int SM_CXSCREEN = 0;
public const int SM_CYSCREEN = 1;
public const int SRCCOPY = 13369376;

[DllImport("gdi32.dll", EntryPoint = "DeleteDC")]
public static extern IntPtr DeleteDC(IntPtr hDc);

[DllImport("gdi32.dll", EntryPoint = "DeleteObject")]
public static extern IntPtr DeleteObject(IntPtr hDc);

[DllImport("gdi32.dll", EntryPoint = "BitBlt")]
public static extern bool BitBlt(IntPtr hdcDest, int xDest, int yDest, int wDest, int hDest, IntPtr hdcSource, int xSrc, int ySrc, int RasterOp);

[DllImport("gdi32.dll", EntryPoint = "CreateCompatibleBitmap")]
public static extern IntPtr CreateCompatibleBitmap(IntPtr hdc, int nWidth, int nHeight);

[DllImport("gdi32.dll", EntryPoint = "CreateCompatibleDC")]
public static extern IntPtr CreateCompatibleDC(IntPtr hdc);

[DllImport("gdi32.dll", EntryPoint = "SelectObject")]
public static extern IntPtr SelectObject(IntPtr hdc, IntPtr bmp);

[DllImport("user32.dll", EntryPoint = "GetDesktopWindow")]
public static extern IntPtr GetDesktopWindow();

[DllImport("user32.dll", EntryPoint = "GetDC")]
public static extern IntPtr GetDC(IntPtr ptr);

[DllImport("user32.dll", EntryPoint = "GetSystemMetrics")]
public static extern int GetSystemMetrics(int abc);

[DllImport("user32.dll", EntryPoint = "GetWindowDC")]
public static extern IntPtr GetWindowDC(Int32 ptr);

[DllImport("user32.dll", EntryPoint = "ReleaseDC")]
public static extern IntPtr ReleaseDC(IntPtr hWnd, IntPtr hDc);

/**
* 尺寸
*
*/
public struct SIZE
{
public int cx;
public int cy;
}

/**
* 获取屏幕解图
*/
public static Bitmap GetDesktopImage()
{
//保存截屏的尺寸
SIZE size;
//指向bitmap的句柄
IntPtr hBitmap;
//通过GetDC函数获得指向桌面设备上下文的句柄
IntPtr hDC = GetDC(GetDesktopWindow());
//在内存中创建一个兼容的设备上下文
IntPtr hMemDC = CreateCompatibleDC(hDC);
//传递一个常数到GetSystemMetrics，并返回屏幕的x坐标
size.cx = GetSystemMetrics(0);
//传递一个常数到GetSystemMetrics，并返回屏幕的y坐标
size.cy = GetSystemMetrics(1);
//创建与指定的设备环境相关的设备兼容的位图。
hBitmap = CreateCompatibleBitmap(hDC, size.cx, size.cy);
//As hBitmap is IntPtr we can not check it against null. For this purspose IntPtr.Zero is used.
if (hBitmap != IntPtr.Zero)
{
//Here we select the compatible bitmap in memeory device context and keeps the refrence to Old bitmap.
IntPtr hOld = (IntPtr)SelectObject(hMemDC, hBitmap);
//We copy the Bitmap to the memory device context.
BitBlt(hMemDC, 0, 0, size.cx, size.cy, hDC, 0, 0, SRCCOPY);
//We select the old bitmap back to the memory device context.
SelectObject(hMemDC, hOld);
//We delete the memory device context.
DeleteDC(hMemDC);
//We release the screen device context.
ReleaseDC(GetDesktopWindow(), hDC);
//Image is created by Image bitmap handle and stored in local variable.
Bitmap bmp = System.Drawing.Image.FromHbitmap(hBitmap);
//Release the memory for compatible bitmap.
DeleteObject(hBitmap);
//This statement runs the garbage collector manually.
GC.Collect();
//Return the bitmap
return bmp;
}
//If hBitmap is null retunrn null.
return null;
}
}
}

4、获取截屏结果

Bitmap bitmap = ScreenDevice.GetDesktopImage();
IntPtr ip = bitmap.GetHbitmap();//从GDI+ Bitmap创建GDI位图对象
//Imaging.CreateBitmapSourceFromHBitmap方法，基于所提供的非托管位图和调色板信息的指针，返回一个托管的BitmapSource
BitmapSource bitmapSource = System.Windows.Interop.Imaging
.CreateBitmapSourceFromHBitmap(ip, IntPtr.Zero, Int32Rect.Empty, System.Windows.Media.Imaging.BitmapSizeOptions.FromEmptyOptions());
image1.Source = bitmapSource;

完工！