WinApi任务查杀

Question

我有超级简单的WinApi程序。关闭按钮不会破坏程序的进程。应该添加什么？

#include <windows.h> 
#include <stdlib.h> 
#include <string.h> 
#include <tchar.h> 


LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM); 

HINSTANCE hINSTANCE; 

int WINAPI WinMain(HINSTANCE hInstance, 
       HINSTANCE hPrevInstance, 
       LPSTR lpstr, 
       int nCmdShow) { 

// VARIABLES 
    TCHAR className[] = _T("win32api"); 
    TCHAR windowName[] = _T("Protected Window"); 

    WNDCLASSEX wcex; 
    wcex.cbSize = sizeof(WNDCLASSEX); 
    wcex.style = CS_HREDRAW | CS_VREDRAW; 
    wcex.lpfnWndProc = WndProc; 
    wcex.cbClsExtra = 0; 
    wcex.cbWndExtra = 0; 
    wcex.hInstance = hInstance; 
    wcex.hIcon = LoadIcon(NULL, IDI_INFORMATION); 
    wcex.hCursor = LoadCursor(NULL, IDC_ARROW); 
    wcex.hbrBackground = (HBRUSH)COLOR_BACKGROUND; 
    wcex.lpszMenuName = NULL; 
    wcex.lpszClassName = className; 
    wcex.hIconSm = LoadIcon(NULL, IDI_SHIELD); 

    if (!RegisterClassEx(&wcex)) { 
     MessageBox(NULL, _T("Cannot register window"), _T("Error"), MB_OK | MB_ICONERROR); 
     return 0; 
    } 

    HWND hWnd = CreateWindow(className, 
           windowName, 
           WS_OVERLAPPEDWINDOW, 
           CW_USEDEFAULT, 
           CW_USEDEFAULT, 
           300, 
           300, 
           NULL, 
           NULL, 
           hInstance, 
           NULL); 

    if (!hWnd) { 
     MessageBox(hWnd, _T("Call to register windows isn't working"), _T("Error"), NULL); 
     return 1; 
    } 

    hINSTANCE = hInstance; 
    ShowWindow(hWnd, nCmdShow); 
    UpdateWindow(hWnd); 

    MSG msg; 

    while (GetMessage(&msg, hWnd, 0, 0) != 0 || GetMessage(&msg, hWnd, 0, 0) != -1) { 
     TranslateMessage(&msg); 
     DispatchMessage(&msg); 
    } 

    return (int)msg.lParam; 
} 

LRESULT CALLBACK WndProc(HWND hWnd, UINT uInt, WPARAM wParam, LPARAM lParam) { 
    PAINTSTRUCT ps; 
    HDC hdc; 
    switch (uInt) { 
    case WM_PAINT: 
     hdc = BeginPaint(hWnd, &ps); 
     TextOut(hdc, 10, 20, _T("Text sample right here boyz."), _tcsclen(_T("Text sample right here boyz."))); 
     EndPaint(hWnd, &ps); 
     break; 
    case WM_DESTROY: 
     PostQuitMessage(0); 
     break; 
    default: 
     return DefWindowProc(hWnd, uInt, wParam, lParam); 
     break; 
    } 

    return 0; 
} 

如果我添加更多的情况

case WM_CLOSE: 
    PostQuitMessage(0); 
    break; 

它不关闭所有（按关闭按钮没有做任何事情）。任何其他提示都非常感谢。

Answer 1

你的消息循环是错误的，原因有二：

1. 您呼叫GetMessage()两次。不要这样做！想想如果你这样做会发生什么。如果||左侧的GetMessage()呼叫检测到WM_QUIT（它不能，请参阅下面的内容），它将返回0.这将导致||在右侧调用GetMessage()，忽略WM_QUIT，并阻止该循环，直到稍后收到新消息。你应该叫GetMessage()每循环迭代一次，然后根据需要在返回值作用：通过HWND（don't do that!）

   BOOL bRet; 
   
   do 
   { 
       bRet = GetMessage(&msg, hWnd, 0, 0); 
       if (bRet == 0) break; 
       if (bRet == -1) 
       { 
        // handle the error and possibly exit 
       } 
       else 
       { 
        TranslateMessage(&msg); 
        DispatchMessage(&msg); 
       } 
   } 
   while (1); 
   

2. 但是，你也过滤消息，因此它只会返回的消息通过PostMessage()发布到指定的HWND。 PostQuitMessage()将其WM_QUIT消息发布到调用线程本身的输入队列，而不是HWND。所以过滤将永远不会看到WM_QUIT消息。为了让WM_QUIT打破循环，您需要完全停止过滤HWND，或者至少定期进行未经过滤的呼叫。

您的消息循环应该看起来像这样。这是标准消息循环：

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

注意，在这种情况下，there is no need to handle -1 from GetMessage()!。

Answer 2

要关闭应用程序，您需要销毁该窗口。通常这是通过以下两种方式之一完成的：

1. 您的WM_CLOSE处理程序调用DestroyWindow。
2. 在您做完事情后，DefWindowProc是否会处理该消息。

你的WndProc有点不同寻常。我经常看到他们写为：

{  
    switch(msg) 
    { 
     case WM_CLOSE: 
      // prompt user, clean stuff up, etc. 
      break; 

     case WM_DESTROY: 
      PostQuitMessage(0); 
      break; 

     // Other cases here. Most will fall out of the switch so that 
     // DefWindowProc can handle them (for other system notifications). 
     // Only return from the case if you really don't want anybody else 
     // to handle the message. 
    } 

    return DefWindowProcW(hwnd, msg, wParam, lParam); 
} 

对于细节上WM_CLOSE，看到https://msdn.microsoft.com/en-us/library/windows/desktop/ms632617(v=vs.85).aspx，具体说，你必须调用DestroyWindow或让DefWindowProc做到这一点。