.NET获取当前鼠标所在位置像素的颜色

class CallWin32GDIAPI
{
private const int SM_CXSCREEN = 0x00000000;//屏幕的横坐标
private const int SM_CYSCREEN = 0x00000001;//纵坐标
private const int SRCCOPY = 0x00CC0020;//光栅操作一参数

[DllImport("GDI32.dll", EntryPoint = "DeleteDC")]
public static extern IntPtr DeleteDC(IntPtr hdc);

[DllImport("GDI32.dll", EntryPoint = "DeleteObject")]
public static extern IntPtr DeleteObject(IntPtr hObject);

[DllImport("GDI32.dll", EntryPoint = "BitBlt")]
public static extern IntPtr BitBlt(IntPtr hdcDest,int nXDest,int nYDest,
int nWidth,int nHight,IntPtr dhcSRC,
int nXSRC,int nYSRC,int dwRop);

[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 hgdiobj);

[DllImport("User32.dll", EntryPoint = "GetDesktopWindow")]
public static extern IntPtr GetDesktopWindow();

[DllImport("User32.dll", EntryPoint = "GetDC")]
public static extern IntPtr GetDC(IntPtr hWnd);

[DllImport("User32.dll", EntryPoint = "GetSystemMetrics")]
public static extern IntPtr GetSystemMetrics(int nIndex);

[DllImport("User32.dll", EntryPoint = "ReleaseDC")]
public static extern IntPtr ReleaseDC(IntPtr hWnd,IntPtr hdc);

/// <summary>
/// 返回像素的颜色
/// </summary>
/// <returns></returns>
internal static Bitmap GetDesktop()
{
//屏幕分辨率宽与高,以像素为单位
int Xscreen;
int Yscreen;
IntPtr hBmp;
//检索指定窗口句柄
IntPtr hdcScreen = GetDC(GetDesktopWindow());
//创建一个与设备兼容的内在设备上下文环境
IntPtr hdcCompatible = CreateCompatibleDC(hdcScreen);
//得到屏幕分辨率宽与高,以像素为单位
Xscreen = (int)GetSystemMetrics(SM_CXSCREEN);
Yscreen = (int)GetSystemMetrics(SM_CYSCREEN);
//创建与设备相兼容的位图
hBmp = CreateCompatibleBitmap(hdcScreen, Xscreen, Yscreen);

if (hBmp != IntPtr.Zero)
{
//将位图对象指定到相关的设备上下文环境中
IntPtr hOldBmp = (IntPtr)SelectObject(hdcCompatible, hBmp);
//对位图的像素进行转换
BitBlt(hdcCompatible, 0, 0, Xscreen, Yscreen, hdcScreen, 0, 0, SRCCOPY);
//SRCCOPY:将源矩形区域直接拷贝到目标矩形区域
SelectObject(hdcCompatible, hOldBmp);
//释放系统资源
DeleteDC(hdcCompatible);
ReleaseDC(GetDesktopWindow(), hdcScreen);
//根据返回的句柄创建位图对象
Bitmap bmp = System.Drawing.Image.FromHbitmap(hBmp);
DeleteObject(hBmp);
//强制进行垃圾回收
GC.Collect();

return bmp;
}
return null;
}
}