线索：用Spy++查看调用这个函数后的窗体的属性，发现Owner Window变了

baidu没找到。

大部分MSDN上都有答案，b57K9s2c8@1M7q4)9K6b7g2)9J5c8W2)9J5c8X3#2K6k6r3&6Q4x3X3g2E0K9h3y4J5L8%4y4G2k6Y4c8Q4x3X3g2U0L8$3#2Q4x3V1k6W2L8W2)9J5k6s2g2K6i4K6u0r3L8r3W2T1M7X3q4J5P5g2)9J5c8Y4N6A6L8X3c8G2N6%4y4Q4x3V1k6V1k6i4y4C8N6r3!0H3i4K6u0r3L8i4x3$3x3K6x3#2z5e0q4Q4x3U0S2$3i4K6y4p5N6Y4y4Q4x3X3f1^5y4g2)9J5z5g2)9J5k6h3q4K6M7s2R3`.

在win95的时代，GWL_HWNDPARENT这个参数是用来修改父窗口的。现在不用了，

MSDN: You must not call SetWindowLong with the GWL_HWNDPARENT index to change the parent of a child window. Instead, use the SetParent function.

你的代码就是将父窗口修改成了1028这个窗口句柄。

至于你说的额外存储空间，
MSDN: The function also sets the 32-bit (long) value at the specified offset into the extra window memory.

nIndex [in]
Type: int

The zero-based offset to the value to be set. Valid values are in the range zero through the number of bytes of extra window memory, minus the size of an integer. To set any other value, specify one of the following values.

因此，你的代码用的是other value，和额外储存空间没有关系。实际上，额外存储空间需要你自己注册窗口类。

Reserve extra window memory by specifying a nonzero value in the cbWndExtra member of the WNDCLASSEX structure used with the RegisterClassEx function.

过来学习

这个看MSDN，里面有对应的参数的详细说明！

看了下win32k.sys，LZ你这invoke SetWindowLong,hWnd,-8,1028发错了吧。

一般情况下我虚拟机里面窗口、钩子什么的句柄数目加起来不超过1024个，父窗口句柄不会是1028。
只有创建了很多窗口下才可能到1028个，句柄才有可能是1028