为何子窗体不在WinMain里面创建，而在WM_CREATE里面创建呢

为什么子窗体不在WinMain里面创建，而在WM_CREATE里面创建呢？
网上搜索了很多窗体上添加按钮或者其他子窗体的程序，几乎都是如下


#include &lt;windows.h&gt;

/*  Declare Windows procedure  */
LRESULT CALLBACK WindowProcedure (HWND, UINT, WPARAM, LPARAM);

/*  Make the class name into a global variable  */
char szClassName[ ] = "WindowsApp";

int WINAPI WinMain (HINSTANCE hThisInstance,
                    HINSTANCE hPrevInstance,
                    LPSTR lpszArgument,
                    int nFunsterStil)

{
    HWND hwnd;               /* This is the handle for our window */
    MSG messages;            /* Here messages to the application are saved */
    WNDCLASSEX wincl;        /* Data structure for the windowclass */

    /* The Window structure */
    wincl.hInstance = hThisInstance;
    wincl.lpszClassName = szClassName;
    wincl.lpfnWndProc = WindowProcedure;      /* This function is called by windows */
    wincl.style = CS_DBLCLKS;                 /* Catch double-clicks */
    wincl.cbSize = sizeof (WNDCLASSEX);

    /* Use default icon and mouse-pointer */
    wincl.hIcon = LoadIcon (NULL, IDI_APPLICATION);
    wincl.hIconSm = LoadIcon (NULL, IDI_APPLICATION);
    wincl.hCursor = LoadCursor (NULL, IDC_ARROW);
    wincl.lpszMenuName = NULL;                 /* No menu */
    wincl.cbClsExtra = 0;                      /* No extra bytes after the window class */ 
 
    wincl.cbWndExtra = 0;                      /* structure or the window instance */
    /* Use Windows's default color as the background of the window */
    wincl.hbrBackground = (HBRUSH) COLOR_BACKGROUND;

    /* Register the window class, and if it fails quit the program */
    if (!RegisterClassEx (&wincl))
        return 0;

    /* The class is registered, let's create the program*/
    hwnd = CreateWindowEx (
           0,                   /* Extended possibilites for variation */
           szClassName,         /* Classname */
           "Windows App",       /* Title Text */
           WS_OVERLAPPEDWINDOW, /* default window */
           CW_USEDEFAULT,       /* Windows decides the position */
           CW_USEDEFAULT,       /* where the window ends up on the screen */
           544,                 /* The programs width */
           375,                 /* and height in pixels */
           HWND_DESKTOP,        /* The window is a child-window to desktop */
           NULL,                /* No menu */
           hThisInstance,       /* Program Instance handler */ 
 
           NULL                 /* No Window Creation data */
           );

    /* Make the window visible on the screen */
    ShowWindow (hwnd, nFunsterStil);

//===================曾经把下面那块代码移动到这里调整下hwnd和instance，运行正常========

    /* Run the message loop. It will run until GetMessage() returns 0 */
    while (GetMessage (&messages, NULL, 0, 0))
    {
        /* Translate virtual-key messages into character messages */
        TranslateMessage(&messages);
        /* Send message to WindowProcedure */
        DispatchMessage(&messages);
    }

    /* The program return-value is 0 - The value that PostQuitMessage() gave */
    return messages.wParam;
}


/*  This function is called by the Windows function DispatchMessage()  */

LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch (message)                  /* handle the messages */
    {
        case WM_CREATE: {
//=================这里开始创建子窗体，需要传入父窗体的hwnd以及hInstance===============
CreateWindowEx(
  NULL,
  "Edit",
  0,
  WS_CHILD | WS_VISIBLE | WS_BORDER | WS_GROUP | WS_TABSTOP | ES_WANTRETURN,
  0,0,200,200,
  hwnd,
  110,
  ((LPCREATESTRUCT)lParam)-&gt;hInstance,
  NULL);
SetFocus(GetDlgItem(hwnd,IDC_EDITBOX));
//=========================================================================================
             break;
             }
        case WM_DESTROY: 
 
            PostQuitMessage (0);       /* send a WM_QUIT to the message queue */
            break;
        default:                      /* for messages that we don't deal with */
            return DefWindowProc (hwnd, message, wParam, lParam);
    }

    return 0;
}

望高手指导下
[解决办法]
其实子窗口是可以在 WinMain 里创建的，也可以正常运行。
但由于创建的子窗口需要保存其句柄，所以需要定义一个static局部变量


static HWND hChild;
hChild = CreateWindow(...);

一般的习惯是在wndproc里定义static局部变量，而不是在 WinMain() 中。这样的好处也是显而易见的，一来保持了 WinMain 中的清爽干净；二来当有多个窗口Wnd_i和窗口过程时WndProc_i，将与Wnd_i相关的变量定义在WndProc_i中也便于管理
[解决办法]
一般主窗口是在winmain中创建的，但子窗口等，为了和主窗口建立父子关系，则需要在主窗口创建完成后创建，WM_CREATE是窗口接收到的第一个消息，因此，子窗口大多在这里创建

为何子窗体不在WinMain里面创建而在

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