win32 SetFocus问题

[无忧老猪]

我在用win32 api写程序。
程序是单线程的，即只有WinMain函数这一个主线程。
我遇到的问题抽象描述如下：
程序的主窗口（即frame窗口）中，有两个子窗口A和B。
A中有一个子窗口C，他是一个标准的edit控件。
B中有一个子窗口D，他是我自己实现的一个窗口，功能类似于edit。
我在D窗口的WM_LBUTTONDOWN消息处理中，调用SetFocus，使得D能够响应键盘输入。
本来这一切都是正常的。
但问题是，如果鼠标点击一下窗口C的内部，使得C获得Focus。
然后，再点击窗口D的内部，无论如何点击，D都无法获得Focus了。
SetFocus(hwnd)之后， GetLastError返回值为5。

我已经检查了我调用SetFocus(hwnd)时传入的窗口句柄，句柄是完全正确的。

[无忧老猪]

晕倒。在下的问题无人问津啊。

[fishion]

在D窗口中点击了就不需要调用SetFocus了

[davidyu720]

贴一下代码。 或者参考http://stackoverflow.com/questions/9643536/setfocus-fails-with-a-valid-window-handle

[Eleven]

你的代码里是怎么写的？

[无忧老猪]

我把程序简化了一下，问题有点变化，但还是不正常。
只要点击一下frame上面的那个edit控件，我自己的窗口就无法获得光标了。

#include <windows.h>
#include <commctrl.h>

#define    FAIL      (-1)
#define    SUCCESS   (0)

HINSTANCE g_hInstance;
TCHAR     szAppName[] = TEXT ("demo_app") ;


HWND    hwnd_frame, hwnd_my_edit, hwnd_edit;

TCHAR szMyEditWinClassName[] = TEXT ("my_edit") ;
TEXTMETRIC textmetric;
int cxChar;
int cyChar;

char  test_buf[2048] = "hello";

int cur_data_len=5;

LRESULT CALLBACK my_edit_WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    HDC hdc ;
    PAINTSTRUCT ps ;
    
    switch (message)
    {
        case WM_CREATE:

            hdc = CreateIC (TEXT("DISPLAY"), NULL, NULL, NULL) ;
            SelectObject (hdc, GetStockObject(SYSTEM_FIXED_FONT)) ;
            GetTextMetrics(hdc, &textmetric) ;
            DeleteObject (SelectObject (hdc, GetStockObject(SYSTEM_FONT))) ;
            DeleteDC (hdc) ;

            cxChar = textmetric.tmAveCharWidth ;
            cyChar = textmetric.tmHeight + textmetric.tmExternalLeading ;

            CreateCaret(hwnd, NULL, cxChar, cyChar);

            return 0 ;


        case WM_PAINT :
            hdc = BeginPaint (hwnd, &ps) ;
            SelectObject (hdc, GetStockObject(SYSTEM_FIXED_FONT)) ;

    		TextOutA(hdc, 0, 0, test_buf, cur_data_len) ; 

            DeleteObject (SelectObject (hdc, GetStockObject(SYSTEM_FONT))) ;
  			EndPaint (hwnd, &ps) ;
			return 0 ;
            
     	case 	 WM_CHAR:
        {
                test_buf[cur_data_len]=wParam;
                cur_data_len++;

                SetCaretPos(cur_data_len*cxChar, 0);
                InvalidateRect (hwnd, NULL, TRUE) ;
          		return 0 ;
          }

     	case 	 WM_SETFOCUS:
        {
                ShowCaret(hwnd);
          		return 0 ;
          }

     	case 	 WM_KILLFOCUS:
        {
                HideCaret(hwnd);
          		return 0 ;
          }
        case WM_LBUTTONDOWN:
            {
                SetFocus(hwnd);
                SetCaretPos(cur_data_len*cxChar, 0);
                ShowCaret(hwnd);
                return 0;

            }
    }
    
    return DefWindowProc (hwnd, message, wParam, lParam) ;
}

int register_my_edit_win()
{
    WNDCLASS    sub_wndclass;
    sub_wndclass.style      = CS_HREDRAW | CS_VREDRAW| CS_DBLCLKS;
    sub_wndclass.lpfnWndProc= my_edit_WndProc;
    sub_wndclass.cbClsExtra = 0;
    sub_wndclass.cbWndExtra = 0;
    sub_wndclass.hInstance  = g_hInstance;
    sub_wndclass.hIcon      = LoadIcon (g_hInstance, IDI_APPLICATION);
    sub_wndclass.hCursor    = LoadCursor (NULL, IDC_ARROW);
    sub_wndclass.hbrBackground  = (HBRUSH)GetStockObject(WHITE_BRUSH);
    sub_wndclass.lpszMenuName   = NULL;
    sub_wndclass.lpszClassName  = szMyEditWinClassName;


    if (!RegisterClass (&sub_wndclass))
     {
        MessageBox (NULL, TEXT ("Program requires Windows NT!"),
          szAppName, MB_ICONERROR) ;
        return FAIL;
     }

    return SUCCESS;

}

int reg_sys_win_classes()
{
    INITCOMMONCONTROLSEX icex;           // Structure for control initialization.
    icex.dwSize = sizeof(icex);
    icex.dwICC = ICC_STANDARD_CLASSES|ICC_BAR_CLASSES|ICC_TAB_CLASSES
        |ICC_TREEVIEW_CLASSES|ICC_LISTVIEW_CLASSES;

    InitCommonControlsEx(&icex);

}

TCHAR   szFrameWinClassName[] = TEXT ("my_frame") ;
HWND    hwnd_frame;

LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch (message)
    {
        case WM_CREATE:
            hwnd_edit = CreateWindow (TEXT("edit"), TEXT ("haha"),
                WS_CHILD | WS_VISIBLE,
                CW_USEDEFAULT, CW_USEDEFAULT,
                CW_USEDEFAULT, CW_USEDEFAULT,
                hwnd, NULL, g_hInstance, NULL) ;

            hwnd_my_edit = CreateWindow (szMyEditWinClassName, NULL,
                WS_CHILD | WS_VISIBLE,
                CW_USEDEFAULT, CW_USEDEFAULT,
                CW_USEDEFAULT, CW_USEDEFAULT,
                hwnd, NULL, g_hInstance, NULL) ;
            return 0 ;


        case WM_SIZE:
      	    MoveWindow(hwnd_edit, 	0, 10, 100, 20, TRUE) ;
      	    MoveWindow(hwnd_my_edit,0, 40, 600, 200, TRUE) ;
          	return 0 ;


     	case	WM_CLOSE:
            DestroyWindow (hwnd) ;
            return 0 ;

        case    WM_DESTROY :
            PostQuitMessage (0) ;
            return 0 ;
    }
    return DefWindowProc (hwnd, message, wParam, lParam) ;
}

int register_frame()
{
    WNDCLASS    wndclass;
    wndclass.style      = CS_HREDRAW | CS_VREDRAW;
    wndclass.lpfnWndProc= WndProc;
    wndclass.cbClsExtra = 0;
    wndclass.cbWndExtra = 0;
    wndclass.hInstance  = g_hInstance;
    wndclass.hIcon      = LoadIcon (g_hInstance, IDI_APPLICATION);
    wndclass.hCursor    = LoadCursor (NULL, IDC_ARROW);
    wndclass.hbrBackground  = (HBRUSH)GetStockObject(GRAY_BRUSH);
    wndclass.lpszMenuName   = NULL;
    wndclass.lpszClassName  = szFrameWinClassName;

    if (!RegisterClass (&wndclass))
     {
        MessageBox (NULL, TEXT ("Program requires Windows NT!"),
          szAppName, MB_ICONERROR) ;
        return FAIL;
     }

    return SUCCESS;

}

int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
             PSTR szCmdLine, int iCmdShow)
{

    MSG     msg ;
    HACCEL  hAccel ;

    g_hInstance = hInstance;

    reg_sys_win_classes();
    register_frame();
    register_my_edit_win();
    
    hwnd_frame = CreateWindow (szFrameWinClassName, szAppName,
            WS_OVERLAPPEDWINDOW|WS_MAXIMIZE|WS_CLIPSIBLINGS|WS_CLIPCHILDREN,
            CW_USEDEFAULT, CW_USEDEFAULT,
            CW_USEDEFAULT, CW_USEDEFAULT,
            NULL, NULL, g_hInstance, NULL) ;

    ShowWindow (hwnd_frame, SW_MAXIMIZE) ;
    UpdateWindow (hwnd_frame) ;
;

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

    return msg.wParam ;
}

[gfm688]

其实点击窗口D的内部，D已经Focus了，估计是Caret在那个标准的edit控件KillFocus时被Destroy了，所以没法显示出来，正确的做法是：

  case   WM_SETFOCUS:
  {
    CreateCaret(hwnd, NULL, 1, cyChar);
    SetCaretPos(cur_data_len*cxChar, 0);
    ShowCaret(hwnd);
    return 0 ;
  }

  case   WM_KILLFOCUS:
  {
   HideCaret(hwnd);
   DestroyCaret();
   return 0 ;
  }
  case WM_LBUTTONDOWN:
  {
    SetFocus(hwnd);
    return 0;
  }

[无忧老猪]

gfm688，你太牛了:)