How would I go about disabling the close button? - c

Question

First of all, let me get my point for this:
This is an emergency alert system, it pulls from a website which we manipulate in the back office, the program can be minimized but cannot be closed (easily, at least none of the people that will use it will know how). As you can see, if the program was closed the Emergency Alerts wouldn't be seen/heard....that's an issue. I have to deploy this application on over 200 computers so I want it simple, I don't want to create a scheduled task, etc.. to keep it running. I simply want it to not be easy to close.
See my code, below:
/* example.c
This is a Win32 C application (ie, no MFC, WTL, nor even any C++ -- just plain C) that demonstrates
how to embed a browser "control" (actually, an OLE object) in your own window (in order to display a
web page, or an HTML file on disk). The bulk of the OLE/COM code is in DLL.c which creates a DLL that
we use in this simple app. Furthermore, we use LoadLibrary and GetProcAddress, so our DLL is not
actually loaded until/unless we need it.
NOTE: The DLL we create does not normally use UNICODE strings. If you compile this example as UNICODE,
then you should do the same with DLL.C.
*/
#include <windows.h>
#include "..\CWebPage.h" /* Declarations of the functions in DLL.c */
// A running count of how many windows we have open that contain a browser object
unsigned char WindowCount = 0;
// The class name of our Window to host the browser. It can be anything of your choosing.
static const TCHAR ClassName[] = "EAS";
// Where we store the pointers to CWebPage.dll's functions
EmbedBrowserObjectPtr *lpEmbedBrowserObject;
UnEmbedBrowserObjectPtr *lpUnEmbedBrowserObject;
DisplayHTMLPagePtr *lpDisplayHTMLPage;
DisplayHTMLStrPtr *lpDisplayHTMLStr;
/****************************** WindowProc() ***************************
* Our message handler for our window to host the browser.
*/
LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
if (uMsg == WM_CREATE)
{
// Embed the browser object into our host window. We need do this only
// once. Note that the browser object will start calling some of our
// IOleInPlaceFrame and IOleClientSite functions as soon as we start
// calling browser object functions in EmbedBrowserObject().
if ((*lpEmbedBrowserObject)(hwnd)) return(-1);
// Another window created with an embedded browser object
++WindowCount;
// Success
return(0);
}
if (uMsg == WM_DESTROY)
{
// Detach the browser object from this window, and free resources.
(*lpUnEmbedBrowserObject)(hwnd);
// One less window
--WindowCount;
// If all the windows are now closed, quit this app
if (!WindowCount) PostQuitMessage(0);
return(TRUE);
}
// NOTE: If you want to resize the area that the browser object occupies when you
// resize the window, then handle WM_SIZE and use the IWebBrowser2's put_Width()
// and put_Height() to give it the new dimensions.
return(DefWindowProc(hwnd, uMsg, wParam, lParam));
}
/****************************** WinMain() ***************************
* C program entry point.
*
* This creates a window to host the web browser, and displays a web
* page.
*/
int CALLBACK WinMain(HINSTANCE hInstance, HINSTANCE hInstNULL, LPSTR lpszCmdLine, int nCmdShow)
{
HINSTANCE cwebdll;
MSG msg;
WNDCLASSEX wc;
// Load our DLL containing the OLE/COM code. We do this once-only. It's named "cwebpage.dll"
if ((cwebdll = LoadLibrary("cwebpage.dll")))
{
// Get pointers to the EmbedBrowserObject, DisplayHTMLPage, DisplayHTMLStr, and UnEmbedBrowserObject
// functions, and store them in some globals.
// Get the address of the EmbedBrowserObject() function. NOTE: Only Reginald has this one
lpEmbedBrowserObject = (EmbedBrowserObjectPtr *)GetProcAddress((HINSTANCE)cwebdll, "EmbedBrowserObject");
// Get the address of the UnEmbedBrowserObject() function. NOTE: Only Reginald has this one
lpUnEmbedBrowserObject = (UnEmbedBrowserObjectPtr *)GetProcAddress((HINSTANCE)cwebdll, "UnEmbedBrowserObject");
// Get the address of the DisplayHTMLPagePtr() function
lpDisplayHTMLPage = (DisplayHTMLPagePtr *)GetProcAddress((HINSTANCE)cwebdll, "DisplayHTMLPage");
// Get the address of the DisplayHTMLStr() function
lpDisplayHTMLStr = (DisplayHTMLStrPtr *)GetProcAddress((HINSTANCE)cwebdll, "DisplayHTMLStr");
// Register the class of our window to host the browser. 'WindowProc' is our message handler
// and 'ClassName' is the class name. You can choose any class name you want.
ZeroMemory(&wc, sizeof(WNDCLASSEX));
wc.cbSize = sizeof(WNDCLASSEX);
wc.hInstance = hInstance;
wc.lpfnWndProc = WindowProc;
wc.lpszClassName = &ClassName[0];
RegisterClassEx(&wc);
// Create another window with another browser object embedded in it.
if ((msg.hwnd = CreateWindowEx(0, &ClassName[0], "Emergency Alert System", WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, 0, CW_USEDEFAULT, 0,
HWND_DESKTOP, NULL, hInstance, 0)))
{
// For this window, display a URL. This could also be a HTML file on disk such as "c:\\myfile.htm".
(*lpDisplayHTMLPage)(msg.hwnd, "http://www.google.com");
// Show the window.
ShowWindow(msg.hwnd, nCmdShow);
UpdateWindow(msg.hwnd);
}
// Do a message loop until WM_QUIT.
while (GetMessage(&msg, 0, 0, 0))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
// Free the DLL.
FreeLibrary(cwebdll);
return(0);
}
MessageBox(0, "Can't open cwebpage.dll! You are not protected by Emergency Alerting System. Click OK to terminate this application. Contact the developer, Scott Plunkett.", "ERROR", MB_OK);
return(-1);
}
It took this from an example tutorial I found, I have never done any windows programming before so I had to figure out a quick solution.
I appreciate any and all help on this.

Answer 1

If you create a handler for the WM_SYSCOMMAND message and check for the SC_SYSCLOSE parameter, you can stop it from executing the default action of closing the window.

Answer 2

I noticed it's not an MFC application, so you have to call Win32 Library to enable the feature.
Try this out:http://www.davekb.com/browse_programming_tips:win32_disable_close_button:txt
---EDIT---
Sorry the code did not work out. I did not have resources to debug it.
To disable the X of the window, you can either set CS_NOCLOSE property of WNDCLASSEX:
wc.style = CS_NOCLOSE;//in your code
or rewrite the WM_CLOSE message handler function. Thanks.