Code://Main.h #ifndef MAIN_H #define MAIN_H #define dim(x) (sizeof(x) / sizeof(x[0])) #define IDC_BUTTON_FORM1 1600 #define IDC_BUTTON_FORM2 1605 #define IDC_BUTTON_FORM3 1610 struct WndEventArgs { HWND hWnd; WPARAM wParam; LPARAM lParam; HINSTANCE hIns; }; struct EVENTHANDLER { unsigned int iMsg; LRESULT (*fnPtr)(WndEventArgs&); }; LRESULT fnWndProc_OnCreate (WndEventArgs&); //We need foreward declarations of LRESULT fnWndProc_OnCommand (WndEventArgs&); //the various functions in a main LRESULT fnWndProc_OnClose (WndEventArgs&); //header file so that the event //handlers can be attached below. LRESULT fnForm1_OnCreate (WndEventArgs&); LRESULT fnForm1_OnPaint (WndEventArgs&); LRESULT fnForm1_OnDestroy (WndEventArgs&); LRESULT fnForm2_OnCreate (WndEventArgs&); LRESULT fnForm2_OnPaint (WndEventArgs&); LRESULT fnForm2_OnDestroy (WndEventArgs&); LRESULT fnForm3_OnCreate (WndEventArgs&); LRESULT fnForm3_OnPaint (WndEventArgs&); LRESULT fnForm3_OnClose (WndEventArgs&); const EVENTHANDLER Form1EventHandler[]= { {WM_CREATE, fnForm1_OnCreate}, {WM_PAINT, fnForm1_OnPaint}, {WM_DESTROY, fnForm1_OnDestroy} }; const EVENTHANDLER Form2EventHandler[]= { {WM_CREATE, fnForm2_OnCreate}, {WM_PAINT, fnForm2_OnPaint}, {WM_DESTROY, fnForm2_OnDestroy} }; const EVENTHANDLER Form3EventHandler[]= { {WM_PAINT, fnForm3_OnPaint}, {WM_CLOSE, fnForm3_OnClose} }; #endifCode:// Main.cpp // cl Main.cpp Form1.cpp Form2.cpp Form3.cpp /O1 /Os /GS- /W2 /FeMultipleForms.exe TCLib.lib kernel32.lib user32.lib gdi32.lib // cl Main.cpp Form1.cpp Form2.cpp Form3.cpp /O1 /Os /GS- /MT /FeMultipleForms.exe kernel32.lib user32.lib gdi32.lib // 92,160 Bytes x64 VC19 (VS 2015) asci libcmt linked // 10,752 Bytes x64 VC19 (VS 2015) wide TCLib linked // 9,728 bytes x64 VC19 (VS 2015) asci TCLib linked #ifndef UNICODE #define UNICODE #endif #ifndef _UNICODE #define _UNICODE #endif // Main.cpp //Program displays a main Form/Window/Dialog With Three Buttons on it to simulate #include <windows.h> //a program started from a main Form with three modules/options/modalities within #include <tchar.h> //which it operates. When you click the top button a new Form/Window/Dialog is #include <stdio.h> //created with CreateWindow() of the "Form1" Window Class, and in the WM_CREATE #include "Main.h" //handler of this new window it disables the main form with the three buttons and #include "Form1.h" //therefore is an example of a modal dialog. When you dismiss this modal dialog #include "Form2.h" //and click on Button/Option #2 on the Main Form, a CreateWindow() call creates a #include "Form3.h" //window of "Form2" Window Class, and in the WM_CREATE handler it sets the visi- // bility of the main window to FALSE. const EVENTHANDLER EventHandler[]= //Since we foreward declared above { //the various event handling functions {WM_CREATE, fnWndProc_OnCreate}, //of the various forms, windows, dialogs {WM_COMMAND, fnWndProc_OnCommand}, //above, we can fill out the fields of {WM_CLOSE, fnWndProc_OnClose} //our EVENTHANDLER structures for the }; //various objects. LRESULT fnWndProc_OnCreate(WndEventArgs& Wea) //...for this window it hides or makes invisible the main { //window. After dismssing this window you'll find that you DWORD dwStyle=WS_CHILD|WS_VISIBLE; //can click on the Option #3 button as many times as you like TCHAR szClassName[16]; //because the window-form-dialog it creates neither disables WNDCLASSEX wc; //nor makes invisible the main window. Further note that these //Option #3 windows can be interacted with regardless of what- Wea.hIns=((LPCREATESTRUCT)Wea.lParam)->hInstance; //ever is going on with the other windows. CreateWindow(_T("button"),_T("Option #1"),dwStyle,65,15,120,25,Wea.hWnd,(HMENU)IDC_BUTTON_FORM1,Wea.hIns,0); CreateWindow(_T("button"),_T("Option #2"),dwStyle,65,55,120,25,Wea.hWnd,(HMENU)IDC_BUTTON_FORM2,Wea.hIns,0); CreateWindow(_T("button"),_T("Option #3"),dwStyle,65,95,120,25,Wea.hWnd,(HMENU)IDC_BUTTON_FORM3,Wea.hIns,0); //Register Window Classes For Form1, Form2 and Form3 wc.cbSize=sizeof(WNDCLASSEX), wc.style=CS_HREDRAW | CS_VREDRAW; wc.cbClsExtra=0, wc.cbWndExtra=0; wc.hInstance=Wea.hIns, wc.hIcon=LoadIcon(NULL, IDI_APPLICATION); wc.hIconSm=0, wc.hCursor=LoadCursor(NULL, IDC_ARROW); wc.hbrBackground=(HBRUSH)GetStockObject(WHITE_BRUSH), wc.lpszMenuName=NULL; _tcscpy(szClassName,_T("Form1")), wc.lpszClassName=szClassName; wc.lpfnWndProc=fnForm1_WndProc; RegisterClassEx(&wc); _tcscpy(szClassName,_T("Form2")); wc.lpfnWndProc=fnForm2_WndProc; wc.lpszClassName=szClassName; //Note that a WM_CREATE call is akin to a constructor call in typical RegisterClassEx(&wc); //C++ class architecture. When you receive this call/message Windows //has finished doing what it needs to support the Window object, and _tcscpy(szClassName,_T("Form3")); //is 'passing the ball' to you. In my apps with multiple windows I wc.lpszClassName=szClassName; //typically use the WM_CREATE handler to register any window classes wc.lpfnWndProc=fnForm3_WndProc; //I need in the app, so that I can make CreateWindow() calls when I RegisterClassEx(&wc); //need to instantiate a window of some type. return 0; } long btnForm1_Click(WndEventArgs& Wea) //This is an 'Event Handler' for a click of the top button on the { //main Form. It uses CreateWindowEx() to instantiate a new Window DWORD dwStyle,dwExStyle; //of class "Form1" Note that the last parameter of the call is HWND hDlg; //Wea.hWnd. That is the HWND of the main program Window. The MSG Msg; //last parameter is the Creation Parameters parameter. It can be //retrieved (as can all the others) through the CREATIONSTRUCT a dwStyle = WS_CAPTION | WS_POPUPWINDOW | WS_VISIBLE; //pointer to which is received in the lParam of the WM_CREATE dwExStyle = WS_EX_DLGMODALFRAME | WS_EX_CONTROLPARENT; //message for the newly instantiating Window. hDlg=CreateWindowEx(dwExStyle,_T("Form1"),_T("Form1"),dwStyle,50,25,310,185,Wea.hWnd,(HMENU)0,GetModuleHandle(0),Wea.hWnd); ShowWindow(hDlg,SW_SHOWNORMAL); UpdateWindow(hDlg); while(GetMessage(&Msg,NULL,0,0)) // The IsDialogMessage function determines whether a message is intended for the specified { // dialog box and, if it is, processes the message. If the message has been processed, the if(!IsDialogMessage(hDlg,&Msg)) // return value is nonzero. If the message has not been processed, the return value is zero. { // Because the IsDialogMessage function performs all necessary translating and dispatching of TranslateMessage(&Msg); // messages, a message processed by IsDialogMessage must not be passed to the TranslateMessage DispatchMessage(&Msg); // or DispatchMessage function.If the return value is zero, its not a message for hDlg. So } // process it. } return 0; } long btnForm2_Click(WndEventArgs& Wea) { HWND hWnd; hWnd=CreateWindowEx ( 0, _T("Form2"), _T("Form2"), WS_OVERLAPPEDWINDOW, 200,250,310,185, 0, (HMENU)0, GetModuleHandle(0), Wea.hWnd ); ShowWindow(hWnd,SW_SHOWNORMAL); UpdateWindow(hWnd); return 0; } long btnForm3_Click(WndEventArgs& Wea) { HWND hWnd; hWnd=CreateWindowEx ( 0, _T("Form3"), _T("Form3"), WS_OVERLAPPEDWINDOW, CW_USEDEFAULT,CW_USEDEFAULT,300,260, 0, (HMENU)0, GetModuleHandle(0), Wea.hWnd ); ShowWindow(hWnd,SW_SHOWNORMAL); UpdateWindow(hWnd); return 0; } LRESULT fnWndProc_OnCommand(WndEventArgs& Wea) { switch(LOWORD(Wea.wParam)) { case IDC_BUTTON_FORM1: return btnForm1_Click(Wea); case IDC_BUTTON_FORM2: return btnForm2_Click(Wea); case IDC_BUTTON_FORM3: return btnForm3_Click(Wea); } return 0; } LRESULT fnWndProc_OnClose(WndEventArgs& Wea) //Search And Destroy Mission For Any Form3 { //Windows Hanging Around. HWND hForm; if(MessageBox(Wea.hWnd,_T("Do You Wish To Exit?"),_T("Exit App?"),MB_YESNO)==IDYES) { do //If FindWindow() returns something other { //than zero, it found a window matching hForm=FindWindow(_T("Form3"),_T("Form3")); //the description of what you are looking if(hForm) //for. In that case, send a WM_CLOSE SendMessage(hForm,WM_CLOSE,0,0); //message. If NULL is returned then just else //break out of the loop and terminate the break; //app. I don't believe this code is really }while(TRUE); //necessary, but I left it in. DestroyWindow(Wea.hWnd); PostQuitMessage(0); } return 0; } LRESULT CALLBACK fnWndProc(HWND hwnd, unsigned int msg, WPARAM wParam,LPARAM lParam) { WndEventArgs Wea; for(unsigned int i=0; i<dim(EventHandler); i++) { if(EventHandler[i].iMsg==msg) { Wea.hWnd=hwnd, Wea.lParam=lParam, Wea.wParam=wParam; return (*EventHandler[i].fnPtr)(Wea); } } return (DefWindowProc(hwnd, msg, wParam, lParam)); } int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevIns, LPSTR lpszArgument, int iShow) { TCHAR szClassName[]=_T("Multiple Forms"); WNDCLASSEX wc={}; MSG messages; HWND hWnd; wc.lpszClassName=szClassName; wc.lpfnWndProc=fnWndProc; wc.cbSize=sizeof (WNDCLASSEX); wc.hIcon=LoadIcon(NULL,IDI_APPLICATION); wc.hInstance=hInstance, wc.hCursor=LoadCursor(NULL,IDC_ARROW); wc.hbrBackground=(HBRUSH)COLOR_BTNSHADOW; RegisterClassEx(&wc); hWnd=CreateWindowEx(0,szClassName,szClassName,WS_OVERLAPPEDWINDOW,250,500,260,180,HWND_DESKTOP,0,hInstance,0); ShowWindow(hWnd,iShow); while(GetMessage(&messages,NULL,0,0)) { TranslateMessage(&messages); DispatchMessage(&messages); } return messages.wParam; }Code://Form1.cpp #ifndef UNICODE #define UNICODE #endif #ifndef _UNICODE #define _UNICODE #endif #include <Windows.h> #include <tchar.h> #include "Form1.h" #include "Main.h" LRESULT fnForm1_OnCreate(WndEventArgs& Wea) { CREATESTRUCT* pCreateStruct; HWND hMain; pCreateStruct=(CREATESTRUCT*)Wea.lParam; hMain=(HWND)pCreateStruct->lpCreateParams; SetWindowLongPtr(Wea.hWnd,GWLP_USERDATA,(LONG_PTR)hMain); EnableWindow(hMain,FALSE); return 0; } LRESULT fnForm1_OnPaint(WndEventArgs& Wea) { PAINTSTRUCT ps; HDC hDC; hDC=BeginPaint(Wea.hWnd,&ps); TextOut(hDC,0,0,_T("This Is Form1. It Disables The Main"),36); TextOut(hDC,0,16,_T("Window, And That Makes It Modal. Note"),38); TextOut(hDC,0,32,_T("That We Passed The Handle Of The Main"),37); TextOut(hDC,0,48,_T("Window In The Last Parameter Of The"),35); TextOut(hDC,0,64,_T("CreateWindow() Call, And Retrieved It In"),40); TextOut(hDC,0,80,_T("fnForm1_OnCreate(). We Then Stored It So"),41); TextOut(hDC,0,96,_T("We Could EnableWindow(TRUE) The Main"),36); TextOut(hDC,0,112,_T("Window When This Modal Form Is"),30); TextOut(hDC,0,128,_T("Dismissed."),10); EndPaint(Wea.hWnd,&ps); return 0; } LRESULT fnForm1_OnDestroy(WndEventArgs& Wea) { HWND hMain; hMain=(HWND)GetWindowLongPtr(Wea.hWnd,GWLP_USERDATA); EnableWindow(hMain,TRUE); PostQuitMessage(0); return 0; } LRESULT CALLBACK fnForm1_WndProc(HWND hWnd, unsigned int msg, WPARAM wParam, LPARAM lParam) { WndEventArgs Wea; for(unsigned int i=0; i<dim(Form1EventHandler); i++) { if(Form1EventHandler[i].iMsg==msg) { Wea.hWnd=hWnd, Wea.lParam=lParam, Wea.wParam=wParam; return (*Form1EventHandler[i].fnPtr)(Wea); } } return (DefWindowProc(hWnd, msg, wParam, lParam)); }Code://Form1.h //Needs to be included in Main.cpp because the WM_CREATE handler there #ifndef FORM1_H //references fnForm1_WndProc as the Window Procedure for the Form1 Class. #define FORM1_H //This would be needed to register the class. LRESULT CALLBACK fnForm1_WndProc(HWND, unsigned int, WPARAM, LPARAM); #endifCode://Form2.cpp #ifndef UNICODE #define UNICODE #endif #ifndef _UNICODE #define _UNICODE #endif #include <Windows.h> #include <tchar.h> #include "Main.h" #include "Form2.h" LRESULT fnForm2_OnCreate(WndEventArgs& Wea) { CREATESTRUCT* pCreateStruct; HWND hMain; pCreateStruct=(CREATESTRUCT*)Wea.lParam; hMain=(HWND)pCreateStruct->lpCreateParams; SetWindowLongPtr(Wea.hWnd,GWLP_USERDATA,(LONG_PTR)hMain); ShowWindow(hMain,SW_HIDE); return 0; } LRESULT fnForm2_OnPaint(WndEventArgs& Wea) { PAINTSTRUCT ps; HDC hDC; hDC=BeginPaint(Wea.hWnd,&ps); TextOut(hDC,0,0,_T("This Is Form2. It SW_HIDEs The Main"),36); TextOut(hDC,0,16,_T("Window, And SW_SHOWs It Upon Closing."),37); TextOut(hDC,0,32,_T("This Technique Can Be Used Similiarly"),37); TextOut(hDC,0,48,_T("To A Modal Dialog If It Isn't Necessary To"),42); TextOut(hDC,0,64,_T("View Simultaneously A Form Underneath The"),41); TextOut(hDC,0,80,_T("Dialog With Which You Can't Interact"),36); TextOut(hDC,0,96,_T("Anyway"),6); EndPaint(Wea.hWnd,&ps); return 0; } LRESULT fnForm2_OnDestroy(WndEventArgs& Wea) { HWND hMain; hMain=(HWND)GetWindowLongPtr(Wea.hWnd,GWLP_USERDATA); EnableWindow(hMain,TRUE); ShowWindow(hMain,TRUE); return 0; } LRESULT CALLBACK fnForm2_WndProc(HWND hWnd, unsigned int msg, WPARAM wParam, LPARAM lParam) { WndEventArgs Wea; for(unsigned int i=0; i<dim(Form2EventHandler); i++) { if(Form2EventHandler[i].iMsg==msg) { Wea.hWnd=hWnd, Wea.lParam=lParam, Wea.wParam=wParam; return (*Form2EventHandler[i].fnPtr)(Wea); } } return (DefWindowProc(hWnd, msg, wParam, lParam)); }Code://Form2.h //Needs to be included in Main.cpp because the WM_CREATE handler there #ifndef FORM2_H //references fnForm2_WndProc as the Window Procedure for the Form1 Class. #define FORM2_H //This would be needed to register the class. LRESULT CALLBACK fnForm2_WndProc(HWND, unsigned int, WPARAM, LPARAM); #endifCode://Form3.cpp #ifndef UNICODE #define UNICODE #endif #ifndef _UNICODE #define _UNICODE #endif #include <Windows.h> #include <tchar.h> #include "Main.h" #include "Form3.h" LRESULT fnForm3_OnPaint(WndEventArgs& Wea) { PAINTSTRUCT ps; HDC hDC; hDC=BeginPaint(Wea.hWnd,&ps); TextOut(hDC,0,0,_T("This Is Form3. Not Only Does It Neither"),40); TextOut(hDC,0,16,_T("Hide Nor Disable The Main Window, But"),37); TextOut(hDC,0,32,_T("You'll Find That You Can Create As Many"),39); TextOut(hDC,0,48,_T("Of These As You Like By Continually"),35); TextOut(hDC,0,64,_T("Clicking The Bottom Button On The Main"),38); TextOut(hDC,0,80,_T("Form. However, You'll Have To Drag One"),39); TextOut(hDC,0,96,_T("From On Top Of The Other Because They"),37); TextOut(hDC,0,112,_T("All Appear In The Same Location (I"),34); TextOut(hDC,0,128,_T("Changed That). You May Further Note"),36); TextOut(hDC,0,144,_T("That Since These Windows Are Neither"),36); TextOut(hDC,0,160,_T("Disabled Nor Hidden At Any Time, You"),36); TextOut(hDC,0,176,_T("May Interact With Them Irregardless Of"),38); TextOut(hDC,0,192,_T("The State Of Form1 Or Form2. Pretty"),35); TextOut(hDC,0,208,_T("Neat, Don't You Think?"),22); EndPaint(Wea.hWnd,&ps); return 0; } LRESULT fnForm3_OnClose(WndEventArgs& Wea) { HWND hMain; MessageBox ( Wea.hWnd, _T("Good Way To Release Any Resources, Memory, etc., You May Have Allocated"), _T("Window Close Report!"), MB_OK ); hMain=(HWND)GetWindowLongPtr(Wea.hWnd,GWLP_USERDATA); EnableWindow(hMain,TRUE); DestroyWindow(Wea.hWnd); ShowWindow(hMain,TRUE); return 0; } LRESULT CALLBACK fnForm3_WndProc(HWND hWnd, unsigned int msg, WPARAM wParam, LPARAM lParam) { WndEventArgs Wea; for(unsigned int i=0; i<dim(Form3EventHandler); i++) { if(Form3EventHandler[i].iMsg==msg) { Wea.hWnd=hWnd, Wea.lParam=lParam, Wea.wParam=wParam; return (*Form3EventHandler[i].fnPtr)(Wea); } } return (DefWindowProc(hWnd, msg, wParam, lParam)); }A worthwhile addition to the above program would be modifications to enable resolution independence at altered user DPI (dots per inch) settings.Code://Form3.h //Needs to be included in Main.cpp because the WM_CREATE handler there #ifndef FORM3_H //references fnForm3_WndProc as the Window Procedure for the Form1 Class. #define FORM3_H //This would be needed to register the class. LRESULT CALLBACK fnForm3_WndProc(HWND, unsigned int, WPARAM, LPARAM); #endif
