在c#中使用win32从窗口获取位图:我在哪里出错了

本文关键字：位图 在哪里 错了 出错 获取 窗口 win32 | 更新日期: 2023-09-27 18:01:26

我需要检索与程序相关的所有窗口的屏幕截图。现在我只是想让这个工作的主窗口。

在image = Image.FromHbitmap(mem);之后，我得到的错误是"GDI+中发生的一般错误"。我试图遵循这个教程

http://www.dreamincode.net/forums/topic/34831-taking-a-screen-shot-in-c%23/

我想我把指针弄乱了，特别是在这三行:

        IntPtr oldBmp = (IntPtr)Win32Stuff.SelectObject(mem, windowImage);
        Win32Stuff.BitBlt(mem, 0, 0, windowwidth, windowheight, windowDC, 0, 0, 13369376);
        Win32Stuff.SelectObject(mem, oldBmp);

如果我理解正确，oldBmp和mem指向windowImage，然后mem指向BitBlt的输出，那么我没有得到现在mem指向oldBmp的这行。我试着把它注释出来，看看这是不是搞砸了，但我得到了相同的通用错误。

以下是完整的代码:

public static class Win32Stuff
{
    [DllImport("user32.dll", EntryPoint = "ReleaseDC")]
    public static extern IntPtr ReleaseDC(IntPtr hWnd, IntPtr hDc);
    [DllImport("user32.dll", EntryPoint = "GetWindowDC")]
    public static extern IntPtr GetWindowDC(IntPtr hWnd);
    [DllImport("gdi32", EntryPoint = "CreateCompatibleDC")]
    public static extern IntPtr CreateCompatibleDC(IntPtr hDC);
    [DllImport("gdi32", EntryPoint = "CreateCompatibleBitmap")]
    public static extern IntPtr CreateCompatibleBitmap(IntPtr hDC, int nWidth, int nHeight);
    [DllImport("gdi32", EntryPoint = "SelectObject")]
    public static extern IntPtr SelectObject(IntPtr hDC, IntPtr hObject);
    [DllImport("gdi32", EntryPoint = "BitBlt")]
    public static extern bool BitBlt(IntPtr hDestDC, int X, int Y, int nWidth, int nHeight, IntPtr hSrcDC, int SrcX, int SrcY, int Rop);
    [DllImport("gdi32", EntryPoint = "DeleteDC")]
    public static extern IntPtr DeleteDC(IntPtr hDC);
}
    public static void getScreenShot()
    {
        int windowwidth;
        int windowheight;
        Bitmap image;
        IntPtr windowHandle = Process.GetProcessesByName("firefox")[0].MainWindowHandle;
        IntPtr windowDC = Win32Stuff.GetWindowDC(windowHandle);
        IntPtr mem = Win32Stuff.CreateCompatibleDC(windowDC);
        //need to change this
        windowheight = 1920;
        windowwidth = 1920;
        IntPtr windowImage = Win32Stuff.CreateCompatibleBitmap(windowDC, windowwidth, windowheight);
        IntPtr oldBmp = (IntPtr)Win32Stuff.SelectObject(mem, windowImage);
        Win32Stuff.BitBlt(mem, 0, 0, windowwidth, windowheight, windowDC, 0, 0, 13369376);
        //Win32Stuff.SelectObject(mem, oldBmp);
        image = Image.FromHbitmap(mem);
        Win32Stuff.DeleteDC(mem);
        Win32Stuff.ReleaseDC(windowHandle, mem);
    }

我怎么能看到具体的错误是什么，为什么不会Image.FromHbitmap()输出GDI位图从我的指针?

在c#中使用win32从窗口获取位图:我在哪里出错了

变化

image = Image.FromHbitmap(mem);


image = Image.FromHbitmap(windowImage);
相关文章：