我自己的 C++ 框架（类似 MFC），我可以创建子窗口，但在 WM_CREATE 时无法创建编辑框
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【中文标题】我自己的 C++ 框架（类似 MFC），我可以创建子窗口，但在 WM_CREATE 时无法创建编辑框【英文标题】：My Own C++Framework (MFC-like), i can create child window, but cant create edit box when WM_CREATE 【发布时间】：2012-08-28 18:33:51 【问题描述】：我构建了自己的与 MFC 类似的 c++ 框架，我可以在收到 WM_CREATE 消息时创建子窗口，但我无法处理编辑框，我从Ivan Shcherbakov's post 得到了这个想法，我发布了一个 WM_CREATEMYWINDOW调用 OnCreate 后的消息，并在收到消息时在 OnCreateMyWindow 函数中创建一些东西，当然，它可以工作。但我想知道为什么以及如何解决这个问题。
我的 CWnd 是 CMyWindow，我创建了一个 CBT-hook 来保存新窗口的 HWND 和 CMyWindow*，然后作为 WindowManager 添加到 HWND-WINDOW 映射，消息循环回调函数 MyWndProc，从 WindowManger 获取 CMyWindow* hWnd 参数，然后调用 CMyWindow 的消息函数 OnCreate、OnSize、OnMove ...等，就像 CWnd 类一样。
CMyWindow 看起来很好用，它可以保存所有消息并做一些响应，但是它不能在 WM_CREATE 时创建一个编辑框，它是如此的连线，因为它在 WM_CREATE 时创建了一个具有任何样式的新窗口。
我用vs2010，win7构建的。
MyWindow.h 中的 WindowManager（HWND-WINDOW 映射）
#define WM_CREATEMYWINDOW WM_USER + 123
//the CWindowManager is a map of HWND-CMyWindow
class CMyWindow;
//define the HWND-CMyWindow map
typedef map <HWND, CMyWindow*> CWindowMap;
typedef pair<HWND, CMyWindow*> WindowPair;
typedef map <HWND, CMyWindow*>::iterator WndIterator;
typedef pair<WndIterator, bool> IterBool;
class CWindowManager : private CWindowMap
private:
CWindowManager(void);
~CWindowManager(void);
public:
bool Add(CMyWindow* pwnd); //add a window to map
bool Remove(HWND hwnd); //remove a window by hwnd
void Clear(); //remove all items
CMyWindow* Find(HWND hwnd); //find the window by hwnd
public:
//get CWindowManager instance as singleton pattern
static CWindowManager * GetInstance();
;
CMyWindow 类与 MFC 的 CWnd 类似
class CMyWindow
public:
CMyWindow(void);
~CMyWindow(void);
inline HWND GetSafeHwnd(); //get HWND
//Create a window
bool Create( HINSTANCE hInstance,
TCHAR * szWindowName,
DWORD dwStyle,
RECT& rect,
HWND hParentWnd,
HMENU hMenu,
LPVOID lpParam);
//add the window to WindowManager
void Attach(HWND hwnd);
//remove the window from WindowManager
void Dettach();
//process the WM_CREATE message
virtual int OnCreate(LPCREATESTRUCT ps);
/*
other message function
*/
//process the WM_CREATEMYWINDOW message
virtual void OnCreateMyWindow();
protected:
HWND _hwnd;
HINSTANCE _hInst;
;
MyWindow.cpp 中的 WindowManager 和 CBT-HOOK 部分
#include "StdAfx.h"
#include "LockEx.h"
#include "MyWindow.h"
//window class name
static TCHAR * _MY_WINDOW_CLASS_NAME_ = L"MYWINDOWCLASS";
//window-proc
LRESULT CALLBACK MyWindowProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam);
///an Mutex-Lock class for keep current hwnd of new window, but you can ignore it when using single thread to crate window
static CLockEx gLockInitWnd;
///keep current hwnd of new window
static CMyWindow * gpInitWnd = 0;
///an hook to create new window
static HHOOK ghook = 0;
///set gpInitWnd when create a new window
static void SetInitWnd(CMyWindow * pWnd)
CLockEx::Scoped lock(gLockInitWnd);
gpInitWnd = pWnd;
///clear gpInitWnd after new window created
static void UnsetInitWnd()
CLockEx::Scoped lock(gLockInitWnd);
gpInitWnd = 0;
///get the HWND of new window that is creating
static CMyWindow * GetInitPwnd()
CLockEx::Scoped lock(gLockInitWnd);
return gpInitWnd;
//CBT-Proc for SetWindowsHookEx
static LRESULT CALLBACK MyCBTProc(int nCode, WPARAM wParam, LPARAM lParam)
if (nCode == HCBT_CREATEWND)
//get the new window from gpInitWnd
CMyWindow * pwnd = GetInitPwnd();
if (pwnd)
//first time call this proc
//add this window to WindowManager
pwnd->Attach((HWND)wParam);
return (0);
else
//sencond time call this proc
CREATESTRUCT * cs = ((CBT_CREATEWND *)lParam)->lpcs;
if (!(cs->style & WS_CHILD))
//we can do something here
return (0);
else
return (1); //error, destroy the window
//or, maybe, CallNextHookEx
else
return CallNextHookEx(ghook, nCode, wParam, lParam);
//Create a WH_CBT Hook
static bool HookCrate()
HANDLE hThread = GetCurrentThread();
DWORD dwThreadId = GetThreadId(hThread);
if (hThread)
ghook = SetWindowsHookEx(
WH_CBT,
MyCBTProc, //set the CBT proc
0,
dwThreadId);
if (!ghook)
return false;
return (0);
//Destroy WH_CBT Hook
static void HookDestroy()
if (ghook)
UnhookWindowsHookEx(ghook);
ghook = 0;
///////////////////////////////////////////////
//this is a vector for keep all CMyWindow*
CWindowManager::CWindowManager(void)
CWindowManager::~CWindowManager(void)
clear();
//insert new window
bool CWindowManager::Add(CMyWindow* pwnd)
IterBool ib = insert(WindowPair(pwnd->GetSafeHwnd(), pwnd));
return ib.second;
//remove a window by hwnd
bool CWindowManager::Remove(HWND hwnd)
WndIterator wi = find(hwnd);
if (wi == end( ))
return false;
else
erase(wi);
return true;
//find a window by hwnd
CMyWindow* CWindowManager::Find(HWND hwnd)
WndIterator wi = find(hwnd);
if (wi == end( ))
return (0);
else
return wi->second;
//remove all items
void CWindowManager::Clear()
clear();
//get instance as singleton pattern.
CWindowManager * CWindowManager::GetInstance()
static CWindowManager wm;
return &wm;
注册窗口类，设置WndProc为MyWIndowProc
ATOM RegisteWindowClass(HINSTANCE hInstance, TCHAR * szClassName)
WNDCLASSEX wcex;
wcex.cbSize = sizeof(WNDCLASSEX);
wcex.style = CS_HREDRAW | CS_VREDRAW;
wcex.lpfnWndProc = MyWindowProc;
wcex.cbClsExtra = 0;
wcex.cbWndExtra = 0;
wcex.hInstance = hInstance;
wcex.hIcon = 0;
wcex.hCursor = LoadCursor(NULL, IDC_ARROW);
wcex.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
wcex.lpszMenuName = 0;
wcex.lpszClassName = szClassName;
wcex.hIconSm = 0;
return RegisterClassEx(&wcex);
CMyWindow 类，请注意我在 WM_CREATE 和 WM_CREATEMYWINDOW 消息中的麻烦
CMyWindow::CMyWindow(void)
: _hwnd(0)
, _hInst(0)
CMyWindow::~CMyWindow(void)
inline HWND CMyWindow::GetSafeHwnd()
return _hwnd;
//Craete a window
bool CMyWindow::Create( HINSTANCE hInstance,
TCHAR * szWindowName,
DWORD dwStyle,
RECT& rect,
HWND hParentWnd,
HMENU hMenu,
LPVOID lpParam)
//get safe instance
HINSTANCE hInst = hInstance;
if (!hInstance)
if (!hParentWnd)
return false;
else
hInst = (HINSTANCE) GetWindowLong(hParentWnd, GWL_HINSTANCE);
if (!hInst)
return false;
//register window class
if (!RegisteWindowClass(hInst, _MY_WINDOW_CLASS_NAME_))
DWORD dwErr = GetLastError();
if (dwErr != ERROR_CLASS_ALREADY_EXISTS) //0x00000582
return false;
//claim i am creating
SetInitWnd(this);
//create CBT hook, then this window will add to WindowManager
HookCrate();
//create window
HWND hwnd = CreateWindow(
_MY_WINDOW_CLASS_NAME_,
szWindowName,
dwStyle,
rect.left, rect.right, rect.right - rect.left, rect.bottom - rect.top,
hParentWnd,
hMenu,
hInstance,
lpParam);
//destroy CBT hook
HookDestroy();
if (!hwnd)
return false;
_hwnd = hwnd;
_hInst = hInst;
//show window
ShowWindow(_hwnd, SW_SHOW);
UpdateWindow(_hwnd);
return true;
//add the this window to WindowManager
void CMyWindow::Attach(HWND hwnd)
_hwnd = hwnd;
CWindowManager::GetInstance()->Add(this);
UnsetInitWnd();
//remove the this window to WindowManager
void CMyWindow::Dettach()
CWindowManager::GetInstance()->Remove(_hwnd);
_hwnd = 0;
int CMyWindow::OnCreate(LPCREATESTRUCT ps)
return (0);
void CMyWindow::OnCreateMyWindow()
//the WndProc callback function
LRESULT CALLBACK MyWindowProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
//Get the CMyWindow instance from WindowManager by hWnd
CMyWindow * pwnd = CWindowManager::GetInstance()->Find(hWnd);
//can not find thi window in WindowManager
if (!pwnd) return DefWindowProc(hWnd, message, wParam, lParam);
switch (message)
case WM_CREATE:
//perform the OnCreate function, just like MFC's OnCreate
int r = pwnd->OnCreate(reinterpret_cast<LPCREATESTRUCT>(lParam));
if (r) //some error occurred, will destory the window
return (r);
//!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
//I can not create any edit box in OnCreate function,
//I must do it leater, when the window was created and
//WM_CREATEMYWINDOW was received
::PostMessage(hWnd, WM_CREATEMYWINDOW, 0, 0);
break;
/*
case WM_.....
other message
case WM_.....
*/
case WM_DESTROY:
::PostQuitMessage(0);
break;
case WM_CREATEMYWINDOW:
//!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
//I can not create any edit box in OnCreate function,
//I must do it when WM_CREATEMYWINDOW was received
pwnd->OnCreateMyWindow();
break;
return DefWindowProc(hWnd, message, wParam, lParam);
现在，继承 CMyWindow 类来创建 2 个窗口，第一个窗口将创建第二个带有编辑框的窗口
class CMyWnd2 : public CMyWindow
public:
CMyWnd2(void) : _hCmdEdit(0)
~CMyWnd2(void)
protected:
HWND _hCmdEdit;
//create edit box
virtual void OnCreateMyWindow();
;
class CMyWnd1 : public CMyWindow
public:
CMyWnd1(void)
~CMyWnd1(void)
protected:
virtual int OnCreate(LPCREATESTRUCT ps);
//create window2
virtual void OnCreateMyWindow();
CMyWnd2 _wnd2;
;
int CMyWnd1::OnCreate(LPCREATESTRUCT /*ps*/)
//Can create window2, but can not crate window2's edit-boxs
return (0);
//create window2 with edit box
void CMyWnd1::OnCreateMyWindow()
RECT rect = 0, 0, 400, 300;
_wnd2.Create(this->_hInst,
0,
WS_VISIBLE | WS_POPUP,
rect,
_hwnd,
0,
0);
//create edit box
void CMyWnd2::OnCreateMyWindow()
RECT rect;
GetClientRect(_hwnd, &rect);
_hCmdEdit = CreateWindowEx(
WS_EX_STATICEDGE,
L"EDIT",
NULL,
WS_CHILD | WS_VISIBLE | WS_VSCROLL | ES_LEFT | ES_MULTILINE | ES_AUTOVSCROLL,
0,
rect.bottom - 80,
rect.right - rect.left,
80,
_hwnd,
(HMENU) 100,
(HINSTANCE) GetWindowLong(_hwnd, GWL_HINSTANCE),
NULL);
最后，WinMain函数创建一个CMyWnd1实例
CMyWnd1 mainwnd;
RECT rect;
rect.left = rect.top = 0, rect.right = 500, rect.bottom = 400;
mainwnd.Create(hInstance,
L"MyWindow",
WS_OVERLAPPEDWINDOW,
rect,
0,
0,
0);
while (GetMessage(&msg, NULL, 0, 0))
if (!TranslateAccelerator(msg.hwnd, hAccelTable, &msg))
TranslateMessage(&msg);
DispatchMessage(&msg);
这里一定有我遗漏的东西，谁能帮我解决这个问题？
【问题讨论】：
【参考方案1】：请注意WM_CREATE 消息在CreateWindow() 返回之前发送。这意味着窗口句柄成员_hwnd（注意：不应使用以_和__开头的标识符，它们是为编译器扩展保留的）尚未初始化并且包含0。因此后续CreateWindow()调用失败，因为您必须传递有效的窗口创建子窗口的句柄（具有WS_CHILD 样式）。但它允许用于弹出窗口（@987654326@ 风格）。这很可能是创建 Wnd2 而不是编辑框的原因。
【讨论】：
嗨 Rost，感谢您的帮助！但是，1。我认为 _hwnd 是有效的句柄，否则不应创建 Wnd2，也应使用 WS_CHILD 创建 Wnd2，您可以尝试一下。 2。我尝试在没有任何 cpp 类的情况下使用原始 win32api 的“标准”进程做同样的事情，它工作得很好。那是第一个窗口在 WM_CREATE 中创建了第二个窗口，第二个窗口在他的 WM_CREATE 中创建了一个编辑框。再次感谢您！ 1.您可以通过在WM_CREATE 处理程序中安装断点来检查它。根据您的代码，它应为零。 2. 当然它可以使用 API 代码——因为窗口句柄在WM_CREATE 调用中直接可用——它作为窗口过程参数传递。但不在您的 cpp 代码中...
嗨 Rost，我在 CBT-Hook 回调函数 MyCBTProc 中遇到了错误，当函数调用第二次时，我拒绝了 WS_CHILD 样式的窗口的创建请求。现在，我只是返回了一个零，一切正常！
顺便说一下，WM_CREATE 之前的 _hwnd 必须非零，因为 CBT-Hook 已捕获它并将其放入地图（hwnd-window）。再次感谢您！【参考方案2】：
我知道了，CBThook回调函数出现了一个愚蠢的错误，当第二次调用这个函数时，我拒绝了创建WS_CHILD风格窗口的请求。它只需要返回一个零！请查看 cmets 中的错误。现在它起作用了！谢谢Rost's 提示。
static LRESULT CALLBACK MyCBTProc(int nCode, WPARAM wParam, LPARAM lParam)
if (nCode == HCBT_CREATEWND)
//get the new window from gpInitWnd
CMyWindow * pwnd = GetInitPwnd();
if (pwnd)
//first time call this proc
//add this window to WindowManager
pwnd->Attach((HWND)wParam);
return (0);
else
//sencond time call this proc
return (0);
////
/// below was my stupid code,
////
/*CREATESTRUCT * cs = ((CBT_CREATEWND *)lParam)->lpcs;
if (!(cs->style & WS_CHILD))
//we can do something here
return (0);
else
return (1); //error, destroy the window
//or, maybe, CallNextHookEx
*/
else
return CallNextHookEx(ghook, nCode, wParam, lParam);
【讨论】：
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