Question

i am using C++ win32 API…

i have a Windows messagebox contain OKCANCEL Button…

the messagebox have a close(X-Button) on the right top…

retun1=MessageBox(hDlg,TEXT("Your password will expired,you must change the password"),TEXT("Logon Message"),MB_OK | MB_ICONINFORMATION);

i only want to close the messagebox using the CANCEL Button…

So,i want to disable the X-Button Icon…

i am already try MB_ICONMASK MB_MODEMASK Somethink like that.

But i cant get it,what i need…

How can i Resolve it?

Answer 1

There’s most likely a bigger problem beyond what you’ve given us, but one way to disable the close button is to set the class style to include CS_NOCLOSE, which you can do with a window handle and SetClassLongPtr. Consider the following full example:

#include <windows.h>

DWORD WINAPI CreateMessageBox(void *) { //threaded so we can still work with it
    MessageBox(nullptr, "Message", "Title", MB_OKCANCEL);
    return 0;
}

int main() {
    HANDLE thread = CreateThread(nullptr, 0, CreateMessageBox, nullptr, 0, nullptr);

    HWND msg;
    while (!(msg = FindWindow(nullptr, "Title"))); //The Ex version works well for you

    LONG_PTR style = GetWindowLongPtr(msg, GWL_STYLE); //get current style
    SetWindowLongPtr(msg, GWL_STYLE, style & ~WS_SYSMENU); //remove system menu 

    WaitForSingleObject(thread, INFINITE); //view the effects until you close it
}