在 win32 中，什么时候是将 WM_SETFONT 消息发送给主窗口的静态控件子窗口的正确时间？

我正在尝试找出设置主窗口子窗口静态文本框字体的正确方法。经过大量谷歌搜索，我发现许多结果基本上解释了以下内容：

1. 使用 CreateFont 创建字体对象
2. 向控件发送 WM_SETFONT 消息，引用字体句柄。
3. 当不再需要字体对象时，将其销毁。

在我找到的所有可能的解释中，我都不知道何时发送消息。我是否在处理其他适当消息的同时在 WinProc 中发送它？我找不到对此的良好解释。

至少有一篇 MSDN 文章讨论了在处理消息时设置字体WM_INITDIALOG，但这不是对话框。这只是一个带有静态子文本框的主窗口。

我所做的就是WM_SETFONT在进入消息循环之前发送消息。令我惊讶的是，它起作用了！我之所以感到惊讶，是因为我的理解是，SendMessage直到消息被处理后它才会返回（即“直到窗口过程处理完消息。” - DOCS）。那么，代码到底是如何进入消息循环的呢？

这是我的代码：

#include <windows.h>
#include <windowsx.h>

HWND hMainWind;
HWND hStartButton;
HWND hStopButton;
HWND hStaticBox;
static HFONT hFont;
static LRESULT CALLBACK MainWinProc(HWND, UINT, WPARAM, LPARAM);

#define START_BUTTON 1001
#define STOP_BUTTON  1002

int WINAPI WinMain( HINSTANCE hMainInstance, HINSTANCE hPrevInstance,
                    LPSTR lpCmdLine, int nShowCmd )
{

  MSG Msg = {0};
  WNDCLASSEX MainWinClass;

  MainWinClass.cbSize         = sizeof(WNDCLASSEX);
  MainWinClass.style          = CS_VREDRAW|CS_HREDRAW;
  MainWinClass.lpfnWndProc    = MainWinProc;
  MainWinClass.cbClsExtra     = 0;
  MainWinClass.cbWndExtra     = 0;
  MainWinClass.hInstance      = hMainInstance;

  MainWinClass.hIcon          = LoadIcon(NULL, IDI_APPLICATION);
  MainWinClass.hCursor        = LoadCursor(NULL, IDC_ARROW);
  MainWinClass.hIconSm        = LoadIcon(NULL, IDI_APPLICATION);

  MainWinClass.hbrBackground  = (HBRUSH)COLOR_BACKGROUND;
  MainWinClass.lpszMenuName   = NULL; /*No menu*/
  MainWinClass.lpszClassName  = "TwoButtons"; /* class name to register*/

  if( !RegisterClassEx( &MainWinClass ) )
  {
      MessageBox( NULL, "Window Failed to Register!", "ERROR",
                  MB_ICONEXCLAMATION | MB_OK);
    return 0;
  }

  hMainWind = CreateWindowEx
  (
    WS_EX_LEFT,
    MainWinClass.lpszClassName,
    "TwoButtons",
    WS_OVERLAPPEDWINDOW,
    CW_USEDEFAULT,  /*Default x pos*/
    CW_USEDEFAULT,  /*Default y pos*/
    640,  /*Width*/
    480,  /*Height*/
    HWND_DESKTOP,
    NULL,
    hMainInstance,
    NULL
  );

  hStartButton = CreateWindow
  (
    "BUTTON",
    "START",
    WS_TABSTOP | WS_VISIBLE | WS_CHILD | BS_PUSHBUTTON,
    270,  /*x pos*/
    200,  /*y pos*/
    100,
    50,
    hMainWind,
    (HMENU)START_BUTTON,
    hMainInstance,
    NULL
  );

  hStopButton = CreateWindow
  (
    "BUTTON",
    "STOP",
    WS_TABSTOP | WS_VISIBLE | WS_DISABLED | WS_CHILD | BS_PUSHBUTTON,
    270,
    300,
    100,
    50,
    hMainWind,
    (HMENU)STOP_BUTTON,
    hMainInstance,
    NULL
  );

  /*create a static text box*/
  hStaticBox = CreateWindow
  (
    "STATIC",                       /* lpClassName */
    "Box",                          /* lpWindowName */
    WS_BORDER|WS_CHILD|WS_VISIBLE,  /* dwStyle */
    270,                            /* x */
    100,                            /* y */
    100,                            /* nWidth */
    50,                             /* nHeight */
    hMainWind,                      /* hWndParent */
    NULL,                           /* hMenu */
    hMainInstance,                  /* hInstance */
    (LPVOID)1                       /* lpParam */
  );

  hFont = CreateFont
  (
    24,                   /* cHeight */
    0,                    /* cWidth use default*/
    0,                    /* cEscapement */
    0,                    /* cOrientation */
    FW_NORMAL,            /* cWeight */
    FALSE,                /* bItalic */
    FALSE,                /* bUnderline */
    FALSE,                /* bStrikeOut */
    DEFAULT_CHARSET,      /* iCharSet */
    OUT_DEFAULT_PRECIS,   /* iOutPrecision */
    CLIP_DEFAULT_PRECIS,  /* iClipPrecision */
    DEFAULT_QUALITY,      /* iQuality */
    DEFAULT_PITCH,        /* iPitchAndFamily */
    "Arial"               /* pszFacename */
  );

  /* Make the main window visible on the screen */
  ShowWindow(hMainWind, nShowCmd);
  UpdateWindow(hMainWind);

  /*Set up the font for the static text box*/
  SendMessage ( hStaticBox, WM_SETFONT, (WPARAM) hFont, TRUE );

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

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

/* This function is called by DispatchMessage()  */
static LRESULT CALLBACK MainWinProc(  HWND hWind, UINT Message, WPARAM wParam,
                                      LPARAM lParam )
{
  switch(Message) /* handle the message */
  {
    case WM_DESTROY:
      DeleteObject(hFont);
      PostQuitMessage(0); /* sends a WM_QUIT to the message queue */
      break;

    case WM_COMMAND:
      if( HIWORD( wParam ) == BN_CLICKED )  /*A button was clicked*/
      {
        switch ( LOWORD(wParam) ) /*Which button?*/
        {
          case START_BUTTON:
            Button_Enable( hStartButton, FALSE );
            Button_Enable( hStopButton,  TRUE );
            SetWindowText( hStaticBox, "START" );
            break;

          case STOP_BUTTON:
            Button_Enable( hStartButton, TRUE );
            Button_Enable( hStopButton,  FALSE );
            SetWindowText( hStaticBox, "STOP" );
            break;
        }
      }
    default:  /* Pass on messages not handled here */
      return DefWindowProc (hWind, Message, wParam, lParam);
  }
  return 0;
}