我正在使用 OpenGL 编写 MDI 图形应用程序。我有一个类 ControllerGL
,它基于 Controller
类,它将具有用于绘制到 MDI 子级的方法(其中一些方法需要它们自己的线程)。创建子窗口时,我将 WNDCLASSEX
的 cbWndExtra
设置为 sizeof(Win::Controller*)
并检索指向 ControllerGL 的指针
子窗口过程的 WM_NCCREACTE
类使用 Set/GetWindowLongPtr()
。
我有这个用于 SDI,所以我很确定所有用于设置/检索指向 ControllerGL
类的指针的代码都很好,并且在 MDI 应用程序中主窗口是显示,并且我从 MDI 子窗口过程的 WM_NCCREATE
函数中获得了 ControllerGL
类的功能实例。
resource.rc 文件中的菜单和字符串表:
IDM_MDI MENU
BEGIN
POPUP "&File"
BEGIN
MENUITEM "&New", ID_FILE_NEW
END
POPUP "&Window",
BEGIN
MENUITEM "&Cascade", ID_WINDOW_CASCADE
MENUITEM "Tile &Horizontal", ID_WINDOW_TILEHORIZONTAL
MENUITEM "Tile &Vertical", ID_WINDOW_TILEVERTICAL
MENUITEM "Arrange &Icons", ID_WINDOW_ARRANGEICONS
END
END
STRINGTABLE
BEGIN
IDS_MDI_TITLE "Win32 MDI"
IDS_MDI_CLASSNAME "MDIMAIN"
IDS_MDICHILD_TITLE "MDIChild"
IDS_MDICHILD_CLASSNAME "MDICHILD"
END
这是为 resource.h 文件准备的
#define IDI_MDI 101
#define IDI_MDI_SMALL 102
#define IDI_MDICHILD 103
#define IDI_MDICHILD_SMALL 104
#define IDS_MDI_TITLE 105
#define IDS_MDI_CLASSNAME 106
#define IDS_MDICHILD_TITLE 107
#define IDS_MDICHILD_CLASSNAME 108
#define IDM_MDI 109
#define ID_FILE_NEW 110
#define ID_WINDOW_CASCADE 111
#define ID_WINDOW_TILEHORIZONTAL 112
#define ID_WINDOW_TILEVERTICAL 113
#define ID_WINDOW_ARRANGEICONS 114
#define IDC_MDICHILD_FIRST 50000
ControllerGL 类的 ViewGL 和 ModelGL 类:
namespace Win
{
class ViewGL
{
public:
ViewGL();
~ViewGL();
};
}
class ModelGL
{
public:
ModelGL();
~ModelGL();
};
Controller 类:
#include <windows.h>
namespace Win
{
class Controller
{
public:
Controller();
virtual ~Controller ();
void setHandle(HWND handle);
virtual int close();
virtual int create();
virtual int destroy();
protected:
HWND handle;
};
inline void Controller::setHandle(HWND hWnd) { handle = hWnd; }
inline int Controller::close() { ::DestroyWindow(handle); return 0; }
inline int Controller::create() { return 0; }
inline int Controller::destroy() { return 0; }
}
ControllerGL类
#include "Controller.h"
#include "ViewGL.h"
#include "ModelGL.h"
namespace Win
{
class ControllerGL : public Controller
{
public:
ControllerGL(ModelGL* model, ViewGL* view);
~ControllerGL() {};
private:
ModelGL* modelGL;
ViewGL* viewGL;
};
}
程序.h
#include <windows.h>
namespace Win
{
LRESULT CALLBACK MDIChildWndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam);
}
程序.cpp
#include "procedure.h"
#include "Controller.h"
LRESULT CALLBACK Win::MDIChildWndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
LRESULT returnValue = 0;
Controller *ctrl;
if (uMsg == WM_NCCREATE)
{
CREATESTRUCT* pCreate = (CREATESTRUCT*)(lParam);
MDICREATESTRUCT* pMdiCreate = (MDICREATESTRUCT*)pCreate->lpCreateParams;
ctrl = (Controller*)pMdiCreate->lParam;
SetWindowLongPtr(hWnd, 0, reinterpret_cast<LONG_PTR>(ctrl));
ctrl->setHandle(hWnd);
SetWindowPos(hWnd, 0, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE | SWP_NOZORDER | SWP_FRAMECHANGED);
}
else
ctrl = reinterpret_cast<Controller *>(GetWindowLongPtr(hWnd, 0));
if (!ctrl)
return DefMDIChildProc(hWnd, uMsg, wParam, lParam);
switch (uMsg)
{
case WM_CREATE:
//returnValue = ctrl->create(); For when ControllerGL works properly
break;
case WM_CLOSE:
//returnValue = ctrl->close();
break;
case WM_DESTROY:
//returnValue = ctrl->destroy();
break;
}
//return returnvalue;
return DefMDIChildProc(hWnd, uMsg, wParam, lParam);
}
主要.cpp
#include <windows.h>
#include "ControllerGL.h"
#include "ModelGL.h"
#include "ViewGL.h"
#include "procedure.h"
#include "resource.h"
#define MAX_LOADSTRING 100
char g_szMDIChild_Title[MAX_LOADSTRING];
char g_szMDIChild_ClassName[MAX_LOADSTRING];
static HINSTANCE g_hInst;
static HWND g_hMDI;
static HWND g_hMDIClient;
static LRESULT CALLBACK MDIWndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam) {
switch (uMsg)
{
case WM_CREATE:
{
DragAcceptFiles(hWnd, TRUE);
CLIENTCREATESTRUCT ccs;
ccs.hWindowMenu = GetSubMenu(GetMenu(hWnd), 1);
ccs.idFirstChild = IDC_MDICHILD_FIRST;
g_hMDIClient = CreateWindowEx(0,
"mdiclient",
NULL,
WS_VISIBLE | WS_CHILD | WS_CLIPCHILDREN | WS_VSCROLL | WS_HSCROLL,
CW_USEDEFAULT,
CW_USEDEFAULT,
CW_USEDEFAULT,
CW_USEDEFAULT,
hWnd,
0,
g_hInst,
(void*)(&ccs));
if (!g_hMDIClient)
MessageBox(hWnd, "Could not create MDI client!", "Error!", MB_OK | MB_ICONERROR);
return 0;
}
break;
case WM_CLOSE:
DestroyWindow(hWnd);
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
case WM_COMMAND:
{
switch LOWORD(wParam)
{
case ID_FILE_NEW:
{
ModelGL model;
Win::ViewGL view;
Win::ControllerGL glCtrl(&model, &view);
HWND hChild = CreateWindowEx(WS_EX_MDICHILD,
g_szMDIChild_ClassName,
g_szMDIChild_Title,
WS_CHILD | WS_VISIBLE | WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT,
CW_USEDEFAULT,
CW_USEDEFAULT,
CW_USEDEFAULT,
g_hMDIClient,
NULL,
g_hInst,
(LPVOID)&glCtrl);
}
break;
case ID_WINDOW_CASCADE:
PostMessage(g_hMDIClient, WM_MDICASCADE, 0, 0);
break;
case ID_WINDOW_TILEHORIZONTAL:
PostMessage(g_hMDIClient, WM_MDITILE, MDITILE_HORIZONTAL, 0);
break;
case ID_WINDOW_TILEVERTICAL:
PostMessage(g_hMDIClient, WM_MDITILE, MDITILE_VERTICAL, 0);
break;
case ID_WINDOW_ARRANGEICONS:
PostMessage(g_hMDIClient, WM_MDIICONARRANGE, 0, 0);
break;
default:
{
if (LOWORD(wParam) >= IDC_MDICHILD_FIRST)
{
DefFrameProc(hWnd, g_hMDIClient, uMsg, wParam, lParam);
}
else
{
HWND hChild;
hChild = (HWND)SendMessage(g_hMDIClient, WM_MDIGETACTIVE, 0, 0);
if (hChild)
{
SendMessage(hChild, WM_COMMAND, wParam, lParam);
}
}
}
};
}
break;
default:
return DefFrameProc(hWnd, g_hMDIClient, uMsg, wParam, lParam);
}
return 0;
}
int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrevInst, LPSTR lpCmdLine, int nCmdShow) {
UNREFERENCED_PARAMETER(hPrevInst);
UNREFERENCED_PARAMETER(lpCmdLine);
char g_szMDI_Title[MAX_LOADSTRING];
char g_szMDI_ClassName[MAX_LOADSTRING];
LoadString(hInst, IDS_MDI_TITLE, g_szMDI_Title, MAX_LOADSTRING);
LoadString(hInst, IDS_MDI_CLASSNAME, g_szMDI_ClassName, MAX_LOADSTRING);
LoadString(hInst, IDS_MDICHILD_TITLE, g_szMDIChild_Title, MAX_LOADSTRING);
LoadString(hInst, IDS_MDICHILD_CLASSNAME, g_szMDIChild_ClassName, MAX_LOADSTRING);
HACCEL hAccelTable = LoadAccelerators(hInst, MAKEINTRESOURCE(IDI_MDI));
WNDCLASSEX wcex;
ZeroMemory(&wcex, sizeof(WNDCLASSEX));
wcex.cbSize = sizeof(WNDCLASSEX);
wcex.style = CS_HREDRAW | CS_VREDRAW;
wcex.lpfnWndProc = Win::MDIChildWndProc;
wcex.cbClsExtra = 0;
wcex.cbWndExtra = sizeof(Win::Controller*);
wcex.hInstance = hInst;
wcex.hIcon = LoadIcon(hInst, MAKEINTRESOURCE(IDI_MDICHILD));
wcex.hCursor = LoadCursor(nullptr, IDC_ARROW);
wcex.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
wcex.lpszMenuName = nullptr;
wcex.lpszClassName = g_szMDIChild_ClassName;
wcex.hIconSm = LoadIcon(hInst, MAKEINTRESOURCE(IDI_MDICHILD_SMALL));
if (!RegisterClassEx(&wcex))
{
MessageBox(0, "Failed to create MDI child window class", "Error!", MB_ICONEXCLAMATION | MB_OK);
return 0;
}
ZeroMemory(&wcex, sizeof(WNDCLASSEX));
wcex.cbSize = sizeof(WNDCLASSEX);
wcex.style = CS_OWNDC;
wcex.lpfnWndProc = MDIWndProc;
wcex.cbClsExtra = 0;
wcex.cbWndExtra = 0;
wcex.hInstance = hInst;
wcex.hIcon = LoadIcon(hInst, MAKEINTRESOURCE(IDI_MDI));
wcex.hCursor = LoadCursor(0, IDC_ARROW);
wcex.hbrBackground = (HBRUSH)GetStockObject(NULL_BRUSH);
wcex.lpszMenuName = MAKEINTRESOURCE(IDM_MDI);
wcex.lpszClassName = g_szMDI_ClassName;
wcex.hIconSm = LoadIcon(hInst, MAKEINTRESOURCE(IDI_MDI_SMALL));
if (!RegisterClassEx(&wcex))
{
MessageBox(0, "Failed to create MDI main window class", "Error!", MB_ICONEXCLAMATION | MB_OK);
return 0;
}
g_hMDI = CreateWindowEx(0,
g_szMDI_ClassName,
g_szMDI_Title,
WS_VISIBLE | WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT,
CW_USEDEFAULT,
CW_USEDEFAULT,
CW_USEDEFAULT,
0,
0,
hInst,
NULL);
if (g_hMDI == NULL)
{
MessageBox(NULL, "Failed to create MDI main window!", "Error!", MB_ICONEXCLAMATION | MB_OK);
return 0;
}
g_hInst = hInst;
MSG uMsg;
while (GetMessage(&uMsg, 0, 0, 0)) {
if (!TranslateMDISysAccel(g_hMDIClient, &uMsg) &&
!TranslateAccelerator(uMsg.hwnd, hAccelTable, &uMsg))
{
TranslateMessage(&uMsg);
DispatchMessage(&uMsg);
}
};
return (int)uMsg.wParam;
}
使用 FILE>NEW 打开新文档时:
所有子窗口都不可见。
只有第一个子窗口在主窗体的 Windows 菜单中有一个条目,创建任何更多窗口都会删除该条目。
我没有收到任何错误,附加调试器也没有显示任何内容。
有人遇到过这个问题吗?
或者这不是问题而是哥伦布彩蛋,而我遗漏了一些明显的东西?
抱歉,代码太多了。老实说,我确实尝试过修剪它。
最佳答案
我发现您的代码中至少有 2 个主要错误需要修复:
WM_MDICREATE
是应用程序发送到 MDI 客户端窗口以创建 MDI 子窗口的消息。子 WndProc 将收到WM_(NC)CREATE
包含MDICREATESTRUCT*
的消息在lParam
中传递的指针的WM_MDICREATE
(如果您使用CreateMDIWindow()
而不是WM_MDICREATE
,它将为您创建必要的MDICREATESTRUCT
)。但是,您的代码未使用WM_MDICREATE
(或CreateMDIWindow()
)来创建其 MDI 子窗口,您正在使用CreateWindowEx(WS_EX_MDICHILD, ...)
直接,你没有传递MDICREATESTRUCT*
在lpParam
参数,您传递的是ControllerGL*
指针代替。因此,在您的 child WndProc 的WM_(NC)CREATE
中处理程序,CREATESTRUCT::lpCreateParam
字段将是ControllerGL*
指针,不是MDICREATESTRUCT*
指针。你的
ID_FILE_NEW
处理程序正在传递指向CreateWindowEx()
的指针到本地ControllerGL
超出范围并在CreateWindowEx()
之后销毁的对象退出,留下新创建的 MDI 子窗口悬空Controller*
指向所有后续消息的无效内存的指针。您需要动态分配ControllerGL
通过new
对象然后delete
当 MDI 子窗口被销毁时,例如在其WM_(NC)DESTROY
中处理程序。
关于c++ - 为什么在 WM_NCCREATE 之后 MDI 子窗口不存在?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/58517012/