关于C#：SetWindowsHookEx用法的区别

The Difference between to usages of SetWindowsHookEx

首先：我在Windows XP-32位上使用Visual Studio 2010。

现在，我正在尝试编写一个DLL，它将使另一个应用程序能够与低级键盘挂钩一起使用。

即使我可以使用它-现在我想了解原因。

非工作代码：

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#include <Windows.h>
#include <stdio.h>

static HINSTANCE hinst;
static HHOOK kbdHook = NULL;

LRESULT CALLBACK LowLevelKeyboardProc(int nCode, WPARAM wParam, LPARAM lParam)
{
printf(":"); fflush(stdout);
return CallNextHookEx(NULL, nCode, wParam, lParam);
}

DWORD WINAPI ThreadProc(LPVOID lpParameter)
{
MSG msg;

while (GetMessage(&msg, NULL, 0, 0))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}

return 0;
}

BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved)
{
switch (fdwReason)
{
case DLL_PROCESS_ATTACH:
hinst = hinstDLL;
CreateThread(NULL, 0, ThreadProc, NULL, 0, NULL);

kbdHook = SetWindowsHookEx(WH_KEYBOARD_LL, LowLevelKeyboardProc, hinst, 0);
break;
case DLL_PROCESS_DETACH:
UnhookWindowsHookEx(kbdHook);
break;
default:
break;
}

return TRUE;
}

工作代码：

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#include <Windows.h>
#include <stdio.h>

static HINSTANCE hinst;
static HHOOK kbdHook = NULL;

LRESULT CALLBACK LowLevelKeyboardProc(int nCode, WPARAM wParam, LPARAM lParam)
{
printf(":"); fflush(stdout);
return CallNextHookEx(NULL, nCode, wParam, lParam);
}

DWORD WINAPI ThreadProc(LPVOID lpParameter)
{
MSG msg;

kbdHook = SetWindowsHookEx(WH_KEYBOARD_LL, LowLevelKeyboardProc, GetModuleHandle(NULL), 0);
while (GetMessage(&msg, NULL, 0, 0))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}

return 0;
}

BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved)
{
switch (fdwReason)
{
case DLL_PROCESS_ATTACH:
hinst = hinstDLL;
CreateThread(NULL, 0, ThreadProc, NULL, 0, NULL);
break;
case DLL_PROCESS_DETACH:
UnhookWindowsHookEx(kbdHook);
break;
default:
break;
}

return TRUE;
}

唯一的区别是我将SetWindowsHookEx-调用从DllMain移到了ThreadProc。

问题：为什么这一切都不同？