I have the following code to create a 'message only' window, the window is always created fine, the problem happens when it is created.
Process A
...
auto hInstance = ::GetModuleHandle( nullptr );
WNDCLASSEX wcx;
wcx.cbSize = sizeof(wcx);
wcx.style = 0;
wcx.lpfnWndProc = MyWinProc;
wcx.cbClsExtra = 0;
wcx.cbWndExtra = 0;
wcx.hInstance = hInstance;
wcx.hIcon = LoadIcon(NULL, IDI_APPLICATION);
wcx.hCursor = LoadCursor(NULL, IDC_ARROW);
wcx.hbrBackground = (HBRUSH)GetStockObject( WHITE_BRUSH);
wcx.lpszMenuName = L"MainMenu";
wcx.lpszClassName = L"MyDummyClass";
wcx.hIconSm = (HICON)LoadImage(hInstance,
MAKEINTRESOURCE(5),
IMAGE_ICON,
GetSystemMetrics(SM_CXSMICON),
GetSystemMetrics(SM_CYSMICON),
LR_DEFAULTCOLOR);
if (!RegisterClassEx(&wcx))
{
throw "Bad 1.";
}
if (!this->CWnd::CreateEx(0, L"MyDummyClass", L"MyDummyWindow", 0, 0, 0, 0, 0, HWND_MESSAGE, nullptr))
{
throw "Bad 2.";
}
Process B
auto myWnd = FindWindow( L"MyDummyClass");
Now the problem I have is if process A create the window before OnInitDialog is called then process B can find the window.
But if process A creates the window at any other time after the main window was created then process B cannot find the window any longer.
In both cases the message pump is called fine, the window is created as expected, I just cannot FindWindow when I create it after the main application is started.
Why would that be, and how can I work around that?
Use FindWindowEx instead:
To find message-only windows, specify HWND_MESSAGE in the hwndParent
parameter of the FindWindowEx function. In addition, FindWindowEx
searches message-only windows as well as top-level windows if both the
hwndParent and hwndChildAfter parameters are NULL.
Related
When we create a pop up menu we call a function TrackPopupMenuEx . It displays a shortcut menu at the specified location and tracks the selection of items on the shortcut menu .
If you specify TPM_RETURNCMD in the fuFlags parameter, the return value is the menu-item identifier of the item that the user selected. If the user cancels the menu without making a selection, or if an error occurs, the return value is zero.
This command is blocking ie unless we click on menu or outside we are blocked.
I have created a window which has various static items which acts like a popup menu. Is there some function equalient to (TrackPopupMenuEx with TPM_RETURNCMD ) which can tell me which was the last WM_COMMAND CLICKED which is blocking . If a function does not exist , how can we create a good blocking in the view that it doesn't eat up the CPU in wait cycle.
What I did :
In the WM_COMAND I initialize the global variable which is whatIsLastClicked. In my function i wait till this variable is set but it seems to eat cpu.
Some code
WNDCLASSW wc = { 0 };
wc.hbrBackground = (HBRUSH)COLOR_WINDOW;
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hInstance = hInst;
wc.lpszClassName = L"mywindowsclass";
wc.lpfnWndProc = windowprocedure;
//<== all handlers WM_COMMAND defined in this fucntion
if (!RegisterClassW(&wc))
{
return -1; // registration failed
}
HWND hWnd = CreateWindowW(L"mywindowsclass",
L"My window", WS_OVERLAPPEDWINDOW | WS_VISIBLE,
100, 100, 500, 500, NULL, NULL, NULL, NULL);
//POINT : need some blocking code here which is efficient to find what i clicked
I am creating a Win32 application, ASCII only. However, when I create the window, the title bar shows chinese characters, instead of the intended text:
//registering the window class:
WNDCLASSEXA wc = { };
wc.hInstance = hThisInstance;
wc.lpszClassName = g_classname;
wc.lpfnWndProc = WndPrc;
wc.style = 0;
wc.cbSize = sizeof (WNDCLASSEXA);
wc.hIcon = (HICON) LoadImage(GetModuleHandle(NULL),
MAKEINTRESOURCE(IDI_APPICO), IMAGE_ICON, 0, 0, LR_DEFAULTCOLOR);
wc.hIconSm = (HICON) LoadImage(GetModuleHandle(NULL), MAKEINTRESOURCE(IDI_APPICO),
IMAGE_ICON, 0, 0, LR_DEFAULTCOLOR);
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.lpszMenuName = MAKEINTRESOURCE(IDR_MENU);
wc.cbClsExtra = 0; /* no extra bytes after the window class */
wc.cbWndExtra = 0; /* structure or the window instance */
wc.hbrBackground = GetSysColorBrush(COLOR_3DFACE); /*(HBRUSH) GetStockObject(WHITE_PEN);*/
if (!RegisterClassEx(&wc))
return FAIL;
return OK;
g_hwndMain = CreateWindow(g_classname, "Hello World", WS_OVERLAPPEDWINDOW,
g_progsettings.winX,
g_progsettings.winY,
g_progsettings.winWidth,
g_progsettings.winHeight,
0, 0, NULL, 0);
if (!g_hwndMain) {
MessageBox(NULL, "Couldn't make window", "CreateWindowEx",
MB_OK | MB_ICONERROR);
exit(EXIT_FAILURE);
}
if (g_progsettings.winX == -1 && g_progsettings.winY == -1)
centerwin(g_hwndMain);
/* Make the window visible on the screen */
ShowWindow(g_hwndMain, nCmdShow);
UpdateWindow(g_hwndMain);
Here is the titlebar:
When I run the program repeatedly, I still get the same titlebar. UNICODE is not #defined.
Unlike other similar questions, I am not casting a const char * into a LPCWSTR or vice versa, so that shouldn't be the cause of the problem.
Here is my WinMain (a lot of irrelevant details)
INT WINAPI WinMain(HINSTANCE hInst,HINSTANCE hPrevInstance,LPSTR lpszArgument, int nCmdShow)
{
MSG msg;
HACCEL hAccel;
BOOL msgRet;
INITCOMMONCONTROLSEX icex;
if (signal(SIGSEGV, onSegfault) == SIG_ERR) {
errmsg("Failed to register handler for SIGSEGV", "");
return EXIT_FAILURE;
}
icex.dwSize = sizeof(INITCOMMONCONTROLSEX);
icex.dwICC = ICC_STANDARD_CLASSES;
if (InitCommonControlsEx(&icex) == FALSE) {
fmtmsgbox(MB_ICONERROR, "extended common controls err: %s", fmtmsg());
return EXIT_FAILURE;
}
if (winregister(hInst) == FAIL)
errmsg("window class error", "window class");
memset(&g_progsettings, 0, sizeof (settings));
if (g_progsettings.readSettings() == FAIL)
g_progsettings.setDefaults();
mainwindow(hInst, nCmdShow);
hAccel = LoadAccelerators(hInst, MAKEINTRESOURCEA(IDR_ACCEL));
onCreat();
while ((msgRet = GetMessageW(&msg, NULL, 0, 0)) != 0) {
if (msgRet == -1) {
errmsg("GetMessage -1", fmtmsg());
exit(EXIT_FAILURE);
}
if (!g_fd.isdlgmsg(&msg)) {
if (!TranslateAcceleratorW(g_hwndMain, hAccel, &msg)) {
TranslateMessage(&msg);
DispatchMessage(&msg);
}
}
}
return 0;
}
You are creating an Ansi-based window via RegisterClassExA() and CreateWindowA(), but you are running a Unicode-based message loop by calling GetMessageW() (and TranslateAcceleratorW()) instead of GetMessageA() (and TranslateAcceleratorA()), and then you are using DispatchMessageA() to dispatch those messages. Presumably your WndProc is also calling DefWindowProcA() instead of DefWindowProcW(). So, even though you are creating an Ansi window with an Ansi title, the default window painting is not going to draw the title data correctly when processing Unicode messages as Ansi (or vise versa). You should not mix Ansi and Unicode APIs together when handling your windows. If you create an Ansi window, use an Ansi message loop. If you create a Unicode window (which you should be), use a Unicode message loop.
I'm trying to learn some windows and directX programming and I was messing around trying some different things. When suddently my the windows stopped appearing, even tho it was a successful build. I figured I must have messed something up and I undid everything until i got back to the place where I last managed to get the window to appear, but now when I run (with a successful build) it still doesn't show :( And I'm starting to run out of ideas what the problem could be, it so strange. One of the thing I did since last time I got it to work was add some libs directories but I have a hard time seeing how that would affect the program this way. Have anyone of you run in to this problem before, and if so how did you solve it? Here is the code of the func creating the window (and yes I am aware of the infinite loop, it shouldn't cause this problem tho, right?) :
ps. I have also tried changing between WINDCLASSEX and WINDCLASS, with all the functions that need to be change with it, didn't make any difference ds.
int WINAPI wWinMain(HINSTANCE hInstance, HINSTANCE, PWSTR pCmdLine, int nCmdShow){
// Register the window class.
const wchar_t CLASS_NAME[] = L"Sample Window Class";
WNDCLASS wc = { };
wc.lpfnWndProc = WindowProc;
wc.hInstance = hInstance;
wc.lpszClassName = CLASS_NAME;
wc.style = CS_HREDRAW | CS_VREDRAW;
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = (HBRUSH)COLOR_WINDOW;
RegisterClass(&wc);
RECT wr = {0, 0, 500, 400}; // set the size, but not the position
AdjustWindowRect(&wr, WS_OVERLAPPEDWINDOW, FALSE); // adjust the size
// Create the window.
HWND hwnd = CreateWindowEx(
0, // Optional window styles.
CLASS_NAME, // Window class
L"My first window", // Window text
WS_OVERLAPPEDWINDOW, // Window style
CW_USEDEFAULT, CW_USEDEFAULT,//position x,y
wr.right-wr.left, wr.bottom-wr.top,//width, height
NULL, // Parent window
NULL, // Menu
hInstance, // Instance handle
NULL // Additional application data
);
if (hwnd == NULL){
return 0;
}
InitD3D(hwnd);
// Run the message loop.
MSG msg = { };
while (true){
if(PeekMessage(&msg, NULL, 0, 0, PM_REMOVE)){
TranslateMessage(&msg);
DispatchMessage(&msg);
}
else{
}
}
return 0;
}
looks like you need a ShowWindow call in there (unless InitD3D does that, you haven't shown the code)
windows are by default created non-visible, so that you can do various initialization without the user seeing what goes on
as an alternative you can create the window already visible, but generally it's a good idea to keep to a single convention
by the way, you can just use a standard int main, no need to use the Microsoft monstrosity
with GNU toolchain that's all, with Microsoft's tools you then have to tell the linker to accept the standard code, if you use the GUI subsystem, via linker option /entry:mainCRTStartup.
also, the call to non-blocking PeekMessage means your message loop will most likely be a CPU hog
instead, use blocking GetMessage
and remember to exit the loop when GetMessage returns 0 (which indicates a WM_QUIT message has been posted)
I'm trying to create an application in Win32 api with c++ and I want to make it FullScreen without any bar , i succeeded but i still have a problem in the background image. The image is repeated but i want it to be stretched. Have you any idea?
below part from the code :
int WINAPI WinMain (HINSTANCE cetteInstance, HINSTANCE precedenteInstance,
LPSTR lignesDeCommande, int modeDAffichage)
{
HWND fenetrePrincipale;
MSG message;
WNDCLASS classeFenetre;
instance = cetteInstance;
classeFenetre.style = 0;
classeFenetre.lpfnWndProc = procedureFenetrePrincipale;
classeFenetre.cbClsExtra = 0;
classeFenetre.cbWndExtra = 0;
classeFenetre.hInstance = NULL;
classeFenetre.hIcon = LoadIcon(NULL, MAKEINTRESOURCE(IDI_APPLICATION));
classeFenetre.hCursor = LoadCursor(NULL, IDC_ARROW);
// classeFenetre.hbrBackground = (HBRUSH)(1 + COLOR_BTNFACE);
//classeFenetre.hbrBackground = CreatePatternBrush(LoadBitmap( instance, MAKEINTRESOURCE("images\Image1.bmp" ) ) );
HBITMAP hbmp = LoadBitmap(instance,MAKEINTRESOURCE(IDB_BITMAP1));
if(NULL == hbmp)
{
MessageBox(NULL,L"BitMap Loading Failed.",L"Error",MB_ICONEXCLAMATION | MB_OK);
}
else
{
HBRUSH hbr = CreatePatternBrush(hbmp);
if(NULL == hbr)
{
MessageBox(NULL,L"Brush Creation Failed.",L"Error",MB_ICONEXCLAMATION | MB_OK);
}
else
{
//StretchBlt();
HDC hdcMem = GetDC (NULL) ;
HDC wndHDC = GetDC (fenetrePrincipale) ;
StretchBlt(hdcMem, 0, 0, 800, 600, wndHDC, 0, 0, 1280, 1024, SRCCOPY);
classeFenetre.hbrBackground = hbr ;
}
}
classeFenetre.lpszMenuName = NULL;
classeFenetre.lpszClassName = L"classeF";
//fullscreen mode and delete minimize and max buttons
// On prévoit quand même le cas où ça échoue
if(!RegisterClass(&classeFenetre)) return FALSE;
//WS_OVERLAPPEDWINDOW
fenetrePrincipale = CreateWindow(L"classeF", L"Ma premiere fenetre winAPI !",WS_MAXIMIZE|WS_POPUP ,
CW_USEDEFAULT, CW_USEDEFAULT, 800, 630,
NULL,
NULL,//LoadMenu(instance, L"ID_MENU"),
cetteInstance,
NULL);
if (!fenetrePrincipale) return FALSE;
//ShowWindow(fenetrePrincipale, modeDAffichage);
ShowWindow(fenetrePrincipale,SW_MAXIMIZE);
UpdateWindow(fenetrePrincipale);
while (GetMessage(&message, NULL, 0, 0))
{
TranslateMessage(&message);
DispatchMessage(&message);
}
return message.wParam;
}
thanks
You haven't shown the exact code, but it appears that you load a bitmap, create a brush from it, and then set that brush as the brush for your window. Brushes would indeed lead to the repeating-image behavior you report. To get a stretched bitmap, you may skip any brush-related code. Instead, handle the WM_ERASEBKGND message sent to your window. In it, call StretchBlt to paint your bitmap onto the client area of your window. The HDC to paint to is given in the message's wParam argument.
Steps
1, CreateWindowEx to create the window
2, SetWindowPos to place your window on top of all windows and Fullscreen
3, On your windows's WindowProce handle WM_PAINT message
4, Load your bitmap
5, Create a memory dc using CreateCompatibleDC
6, Selet your bitmap into memory dc by calling SelectObject
7, Do the StretchBlt to your actual dc, using the prepared memory dc as the source, you should know the actual width and height of the bitmap for proper stretching
I've got a function:
HWND createMainWindow(P2p_Socket_Machine * toSend){
HWND hMainWnd = CreateWindow(
L"Class",/*(LPCWSTR) nameOfConference.c_str()*/L"Chat", WS_OVERLAPPED | WS_MINIMIZEBOX | WS_SYSMENU,
CW_USEDEFAULT, 0, 600,400,
(HWND)NULL, (HMENU)NULL,
/*(HINSTANCE)hlnstance*/NULL, NULL
);
if (!hMainWnd) {
MessageBox(NULL, L"Cannot create main window", L"Error", MB_OK);
return 0;
}
CreateWindowA("LISTBOX",NULL, WS_CHILD|WS_VISIBLE|WS_BORDER|WS_VSCROLL|LBS_NOTIFY|LBS_MULTIPLESEL,310,30,255,275,hMainWnd,(HMENU)List_Box,NULL,NULL);
CreateWindowExA(NULL,"BUTTON", "Refresh", WS_TABSTOP|WS_VISIBLE|WS_CHILD|BS_DEFPUSHBUTTON,385,310,100,24,hMainWnd,(HMENU)Button_Refresh, NULL ,NULL);
CreateWindowExA(NULL,"BUTTON", "Send", WS_TABSTOP|WS_VISIBLE|WS_CHILD|BS_DEFPUSHBUTTON,385,334,100,24,hMainWnd,(HMENU)Button_Send, NULL ,NULL);
CreateWindowExA(NULL,"BUTTON", "New", WS_TABSTOP|WS_VISIBLE|WS_CHILD|BS_DEFPUSHBUTTON,385,354,100,24,hMainWnd,(HMENU)Button_New, NULL ,NULL);
CreateWindowA("EDIT",0,WS_BORDER|WS_VISIBLE|WS_CHILD|ES_LEFT|ES_MULTILINE|WS_VSCROLL|WS_DISABLED,
10,30,265,275,hMainWnd,(HMENU)Text_Box_Get,NULL,NULL);
CreateWindowA("EDIT",0,WS_BORDER|WS_VISIBLE|WS_CHILD|ES_LEFT|ES_MULTILINE|WS_VSCROLL,
10,320,265,45,hMainWnd,(HMENU)Text_Box_Send,NULL,NULL);
SetWindowLongPtr(hMainWnd,GWLP_USERDATA,(LONG_PTR)toSend);
ShowWindow(hMainWnd, SW_SHOW);
//UpdateWindow(hMainWnd);
return hMainWnd;
}
And this is main part of my program:
int WINAPI WinMain(HINSTANCE hlnstance, HINSTANCE hPrevInstance, LPSTR IpCmdLine, int
nCmdShow)
{
WNDCLASSEX wc;
wc.cbSize = sizeof(wc);
wc.style = CS_HREDRAW | CS_VREDRAW;
wc.lpfnWndProc = MyFunc;
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = hlnstance;
wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
wc.lpszMenuName = NULL;
wc.lpszClassName = L"Class";
wc.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
HWND toSend = createMainWindow(P2pSocket);
//some code
hThread = CreateThread(NULL, 0, ClientThread,
Message2, 0, &dwThreadId);
if (hThread == NULL)
{
cout<<"Create thread filed";
exit(10);
}
while (GetMessage(&msg, NULL, 0, 0)) {
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return msg.wParam;
When i call function createMainWindow() in main part of my program
it works as it should, but when i run it in
my thread(ClientThread) it doesn't work. i've read that i should create windows only in main thread. Is it true? And if it's true, what is the simplest way to call this function from another thead to be done in main thread?
Thanks everyone. Now i know the problem, but i'm stuck with solution.
My client thread code is:
while(1){
vector<HWND> AllHandlers;
pair<string,string> Answer = Pointer->receiveMsgByUdp();
if(!Pointer->isMyLocalAddress(Answer.first)){
int type = messageUdpContentType(Answer.second);
switch(type){
case 0 :
Pointer->sendMsgToIpUdp(Answer.first,"<?xml version='1.0'?><accepted/>");
AllHandlers = getAllHandlersOfElementsOnWindowsByIdentityCode(Pointer->getAllHandlers(),List_Box);
for(vector<HWND>::iterator j = AllHandlers.begin();j!=AllHandlers.end();j++)
if(SendMessageA(*j, LB_FINDSTRINGEXACT, 0, (LPARAM)Answer.first.c_str())==LB_ERR)
SendMessageA(*j, LB_ADDSTRING, 0, (LPARAM)Answer.first.c_str());
break;
case 1 :
AllHandlers = getAllHandlersOfElementsOnWindowsByIdentityCode(Pointer->getAllHandlers(),List_Box);
for(vector<HWND>::iterator j = AllHandlers.begin();j!=AllHandlers.end();j++)
if(SendMessageA(*j, LB_FINDSTRINGEXACT, 0, (LPARAM)Answer.first.c_str())==LB_ERR)
SendMessageA(*j, LB_ADDSTRING, 0, (LPARAM)Answer.first.c_str());
break;
case 2 :
AllHandlers = getAllHandlersOfElementsOnWindowsByIdentityCode(Pointer->getAllHandlers(),List_Box);
for(vector<HWND>::iterator j = AllHandlers.begin();j!=AllHandlers.end();j++)
if((i = SendMessageA(*j, LB_FINDSTRINGEXACT, 0, (LPARAM)Answer.first.c_str()))!=LB_ERR)
SendMessageA(*j,LB_DELETESTRING, 0, (LPARAM)Answer.first.c_str());
break;
case 3 :
userReply = MessageBoxW(NULL, L"Принять приглашение на конференцию?",
L"", MB_YESNO | MB_ICONQUESTION);
if (userReply==IDYES){
//todo: Проверка на создание встречи, в которой уже состоишь
string nameOfConf = fetchNameOfInviteConf(Answer.second);
Pointer->createConference(nameOfConf);
HWND toSendTo = createMainWindow(Pointer);
Pointer->setHandlerInfo(nameOfConf,toSendTo);
Pointer->addNewMemberToConference_ServerType(nameOfConf,Answer.first);
string toSend = string("<?xml version='1.0'?><inviteAccepted>") + nameOfConf + string("</inviteAccepted>");
Pointer->sendMsgToIpUdp(Answer.first,toSend);
}
break;
case 4 :
string nameOfConf = fetchNameOfInviteAcceptConf(Answer.second);
toSend.clear();
Participants.clear();
Participants = Pointer->getCurrentParticipants(nameOfConf);
toSend+="<?xml version='1.0'?>";
toSend+="<conference>";
toSend+="<nameOfConference>";
toSend+=nameOfConf;
toSend+="</nameOfConference>";
for(vector<string>::iterator i = Participants.begin();i!=Participants.end();i++){
toSend+="<participant>" + *i + "</participant>";
}
toSend+="</conference>";
Pointer->addNewMemberToConference_ClientType(nameOfConf,Answer.first);
Pointer->sendToIpTcp(Answer.first,toSend);
break;
}
the function receiveMsgByUdp() stops this thread until receives message. I apologize for lack of knowledge, but what functions can i use or another stuff to solve this. Should i rewrite my method receiveMsgByUdp() to be asynchronous or how can i call function createMainWindow() to be run on main thread?About the last variant : how can i do this in pure winapi, i couldn't found any simple examples. Can someone give code snippet. Thanks one more time)
You can indeed create windows in threads other than the main UI thread. However, those windows will have affinity to the thread that created them and you will need to run a message pump in each and every thread that creates windows.
So whilst you can do what you ask, Win32 is really designed to work with all windows in a process having affinity to the same thread. There's really nothing to be gained from creating multiple UI threads. All you will succeed in doing is making your life extraordinarily and needlessly complex.
You can create windows on "non-main" threads but be aware that those windows are attached to the creation thread, and you need to make sure to implement a message loop there and keep dispatching messages posted on the queue. If you don't do this, your windows are going to freeze.
See:
Using Messages and Message Queues
Message Handling -- About Messages and Message Queues
The system does not automatically create a message queue for each
thread. Instead, the system creates a message queue only for threads
that perform operations which require a message queue. If the thread
creates one or more windows, a message loop must be provided; this
message loop retrieves messages from the thread's message queue and
dispatches them to the appropriate window procedures.
If you create a window in another thread, you will also need to implement a message loop on that thread since queued messages are posted to the message queue of thread which owns the window.