Now I want to dynamically modify the GUI of a running WINDOWS program(assume this program is written in win32 API/MFC), for example, add a button to it's specific position.
But I'm not familiar with WINDOWS GUI programming.
So I want to ask if there is any normal way to implement this feature using win32 API or MFC.
If not, do I need any hacking tips?
You can dynamically create any Windows component by utilizing the CreateWindow function when processing (for example) a WM_COMMAND message inside your WndProc callback function. Or any other message for that matter. Provided that you have a button with an ID of IDC_BUTTON you can create a new button when clicked.
case WM_COMMAND: // process commands
switch (LOWORD(wParam))
{
case IDC_BUTTON: //check for our button ID
HWND hwndButton = CreateWindow(
L"BUTTON", // predefined class name
L"OK", // button text
WS_TABSTOP | WS_VISIBLE | WS_CHILD | BS_DEFPUSHBUTTON, // Styles
10, // x position
10, // y position
75, // width
24, // height
hWnd, // parent handle
(HMENU)IDC_BUTTON2, // button ID
hInst, // module instance
NULL); // lparam, pointer not needed
break;
}
Related
This question already has answers here:
Access a variable from a different switch case (from WM_CREATE to WM_CTLCOLORSTATIC in the WinApi)
(2 answers)
Closed last month.
I have created a basic button in case: WM_CREATE in the windows procedure with the following.
/*The "new_game_button" is declared as type HWND at the
start of the windows procedure function but not initialized.*/
new_game_button = CreateWindow ( "BUTTON", "New Game",
WS_CHILD | WS_BORDER ,
50, 50, 100, 100,
hwnd, NULL, NULL, NULL);
My intent is to create an instructions and "start new game" button as the first thing in my simple tictactoe app. It will immediately show as expected if I give the parameter WS_VISIBLE.
Further in the same case:WM_CREATE if I use the lines
if (!start_Game){ //global variable default is false
ShowWindow( new_game_button, SW_SHOW);
}
The button will show as expected.
Outside of those two cases I cannot get the button to show at a later stage.
Further, if I use one of those two methods to show the button I can never get it to go away using
ShowWindow ( new_game_button, SW_HIDE);
Once the button is showing, it stays for the duration of the programs execution. Doesn't matter which case. Command/Create/Paint
I have tried using
if (start_Game){
ShowWindow( new_game_button, SW_HIDE);
UpdateWindow ( new_game_button );
//UpdateWindow ( hwnd ); tried this as well
}
inside case WM_CREATE.
I have also tried the same SW_HIDE line inside case: WM_COMMAND where a new game is generated (compiles but doesn't hide the button.)
I have tried declaring the button child window outside the WM_CREATE inside the windows procedure function. Then using WM_CREATE to show the window - works -- still WM_COMMAND will not hide the window.
I have also tried creating the button window inside of case:WM_PAINT which works to show the button but not to get rid of it. I have even tried DestroyWindow which just fails. [returns 0]
In trying to understand the behaviour of the button window - I have found that I cannot get
ShowWindow( new_game_button, SW_SHOW);
to work in the case:WM_COMMAND.
You said (in a code comment in the question).
new_game_button is declared as type HWND at the start of the windows procedure function but not initialized.
Each incoming message means a new call to your window procedure. Variables which are local to a function don't retain their value between calls unless they are marked static.
When your window procedure returned from processing WM_CREATE, you lost the value of new_game_button. When you try to use it during WM_COMMAND processing later, it is uninitialized and your program causes undefined behavior by passing it to ShowWindow.
Every comment helped me solve this which I appreciate. I am too new to give reputation sadly.
case WM_CREATE:
{
new_game_button = CreateWindow ("BUTTON", "New Game",
WS_CHILD | WS_BORDER ,
50, 50, 100, 100,
hwnd, (HMENU) 1, NULL, NULL);
if (!start_Game){
ShowWindow( new_game_button, SW_SHOW);
}
}
break;
After I had an ID for the dialog I am able to use GetDlgItem function to show or hide as I please.
new_game_button = GetDlgItem (hwnd, 1);
ShowWindow( new_game_button, SW_HIDE);
I'm a beginner and today is my first day in learning to create Windows application.
I have two buttons.
#define BUTTON_SW 1
#define BUTTON_SW2 2
HWND Button1;
HWND Button2;
Button1 = CreateWindow("button", "Enter", WS_VISIBLE | WS_CHILD, 215, 10, 40, 25, hwnd, HMENU(BUTTON_SW), NULL, NULL);
Button2 = CreateWindow("button", "You'll be gone", WS_VISIBLE | WS_CHILD, 260, 10, 95, 25, hwnd, HMENU(BUTTON_SW2), NULL, NULL);
When Button1 is clicked, how can I hide Button2 or make it lose its WS_VISIBLE flag and reflect current situation correctly, like this?
LONG style = GetWindowLong(Button2,GWL_STYLE);
style = style | WS_VISIBLE; // style = style & ~WS_VISIBLE
SetWindowLong(Button2,GWL_STYLE,style);
This works very well. However, once WS_VISIBLE flag is assigned, button still stays invisible until the first mouseclick on it.
Vice versa, when I use style = style & ~WS_VISIBLE; once WS_VISIBLE flag is removed, button becomes passive (unclickable) but stays visible.
How to fix this? Tried many things that I've found online but couldn't fix it. Also please don't suggest me to buy a decent book, I don't have the money for now.
(P.S: ShowWindow function with SW_HIDE/SW_SHOW somehow doesn't work for me, perhaps I'm using it wrong. Can you help me on how I can hide this Button2 correctly? I'm trying the following command, but nothing happens.)
ShowWindow(GetDlgItem(Button2, 2), SW_HIDE);
#Edit: I've noticed that when I minimize the app and maximize it
again, the state of button updates. But how will it automatically
update the state?
This should work
ShowWindow(Button2, SW_HIDE);
or
ShowWindow(GetDlgItem(DialogHWND, BUTTON_SW2), SW_HIDE);
GetDlgItem needs HWND of the parent window (dialog) as first argument.
In order to a window to reflect changes you must ask the OS to do it.
Learn about RedrawWindow and the invalidated area.
Note that some actions, like resizing or restoring from minimized, automatically makes the OS to invalidate the region and redraw it.
Use:
RedrawWindow(Button2,NULL,NULL,RDW_INVALIDATE | RDW_INTERNALPAINT);
I'm creating a small WinAPI application in C++. I am trying to create a button on my form by using the code:
HWND hwndButton = CreateWindow(
TEXT("BUTTON"),
TEXT("Click Here"),
WS_TABSTOP | WS_VISIBLE | WS_CHILD | BS_PUSHBUTTON, // Styles
10,
10,
100,
30,
hwnd,
NULL,
(HINSTANCE)GetWindowLong(hwnd, GWL_HINSTANCE),
NULL);
This code is based off of an MSDN sample. My issue is that it uses a bold font on the button like this:
When I want to use the standard font like this:
I already have the preprocessor directive at the top of my file to enable visual styles.
#pragma comment(linker,"\"/manifestdependency:type='win32' \
name='Microsoft.Windows.Common-Controls' version='6.0.0.0' \
processorArchitecture='*' publicKeyToken='6595b64144ccf1df' language='*'\"")
What steps should I take to use the standard system wide font?
Thanks
GetStockObject isn't the recommended way of retrieving the GUI font (it doesn't take themes into account, and different fonts can be chosen for buttons, menus, etc). Instead you should use SystemParametersInfo (see Remarks section of GetStockObject).
It is not recommended that you employ this method to obtain the current font used by dialogs and windows. Instead, use the SystemParametersInfo function with the SPI_GETNONCLIENTMETRICS parameter to retrieve the current font. SystemParametersInfo will take into account the current theme and provides font information for captions, menus, and message dialogs.
NONCLIENTMETRICS metrics = {};
metrics.cbSize = sizeof(metrics);
SystemParametersInfo(SPI_GETNONCLIENTMETRICS, metrics.cbSize, &metrics, 0);
HFONT guiFont = CreateFontIndirect(&metrics.lfCaptionFont);
// When you're done with the font, don't forget to call
DeleteObject(guiFont);
There's no such thing as default system wide font for controls, initially you get a control created with "System" font, that's what you see on first picture. When button is created as part of a dialog, it uses a font from dialog template, so using something like "MS Shell Dlg" with appropriate size + WM_SETFONT on a button should give you the same result as on picture 2. Note that there's no physical MS Shell Dlg font on a system, it's mapped to particular font according to registry settings.
Common control manifest has nothing to do with this, behavior has not changed with comctl32 version 6.
The default GUI font is stored in DEFAULT_GUI_FONT, and can be retrieved via
GetStockObject(DEFAULT_GUI_FONT);
To set the font of the button you can use:
HWND yourButton; // use CreateWindow or anything else to get this
SendMessage(yourButton, WM_SETFONT, (LPARAM)GetStockObject(DEFAULT_GUI_FONT), true);
A convenient way of doing this without calling SendMessage on every single child window manually is to use the EnumChildWindows function with the following callback function -
Create the callback function EnumChildProc:
BOOL CALLBACK EnumChildProc(
HWND hWnd,
LPARAM lParam
)
{
HFONT hfDefault = *(HFONT *) lParam;
SendMessageW(hWnd, WM_SETFONT, (WPARAM) hfDefault, MAKELPARAM(TRUE, 0));
return TRUE;
}
At the start of your (w)WinMain function, add the code:
NONCLIENTMETRICSW ncm;
HFONT hfDefault;
ZeroMemory(&ncm, sizeof(NONCLIENTMETRICSW));
ncm.cbSize = sizeof(NONCLIENTMETRICSW);
SystemParametersInfo(SPI_GETNONCLIENTMETRICS, sizeof(NONCLIENTMETRICS), &ncm, FALSE);
hfDefault = CreateFontIndirectW(&ncm.lfMessageFont);
Then, after the ShowWindow call, add this line:
EnumChildWindows(hWnd, EnumChildProc, (LPARAM)&hfDefault);
So I am new to programming in C++ and new to using Visual Studio 2010. Basically I have a FLIR thermal camera; and I need to edit a GUI provided in an eBUS SDK that suits my needs.
What I want to do is open a new dialog box when I click the settings button. I am just not sure what code to use in the button handler to make the dialog box open. I have put different code in the button handler to test it and the settings button works fine.
This is the button handler that the code needs to go into.
void PvSimpleUISampleDlg::OnBnClickedSettings()
{
}
This is the dialog box in the resource file that I want to connect the button to. It is called IDD_SETTINGS. The actual button is called IDB_SETTINGS, not sure if that's relevant.
IDD_SETTINGS DIALOGEX 0, 0, 506, 300
STYLE DS_SETFONT | DS_MODALFRAME | DS_FIXEDSYS | WS_MINIMIZEBOX | WS_MAXIMIZEBOX | WS_POPUP | WS_CAPTION | WS_SYSMENU
CAPTION "Settings"
FONT 8, "MS Shell Dlg", 400, 0, 0x1
BEGIN
DEFPUSHBUTTON "OK",IDOK,449,279,50,14
END
I am not sure what other code to add, but I am completely new so any help/advice you can give no matter how small would be greatly appreciated.
If you are using the MFC framework (the CDialog class), then you can create a new CDialog object using the settings-dialog resource you've created.
The CDialog::DoModal() function is what you want, if you want a simple popup box that grabs your attention until it is dismissed with OK or Cancel.
In your source file:
void PvSimpleUISampleDlg::OnBnClickedSettings()
{
CDialog mySettings( IDD_SETTINGS );
INT_PTR returnCode = -1;
returnCode = mySettings.DoModal();
switch( returnCode ) {
case IDOK :
//gather your input fields here
break;
case IDCANCEL :
//do something
break;
case -1:
default:
//error creating box
}
}
Here is a link for using the CDialog class as a starting point for extracting information from the box once OK is clicked:
https://msdn.microsoft.com/en-us/library/619z63f5.aspx
In my application I am handling the WM_HELP message and then creating a tooltip for a control using this method:
Taken from: http://msdn.microsoft.com/en-us/library/bb760252(v=vs.85).aspx
HWND CreateToolTip(int toolID, HWND hDlg, PTSTR pszText)
{
if (!toolID || !hDlg || !pszText)
{
return FALSE;
}
// Get the window of the tool.
HWND hwndTool = GetDlgItem(hDlg, toolID);
// Create the tooltip. g_hInst is the global instance handle.
HWND hwndTip = CreateWindowEx(NULL, TOOLTIPS_CLASS, NULL,
WS_POPUP |TTS_ALWAYSTIP | TTS_BALLOON,
CW_USEDEFAULT, CW_USEDEFAULT,
CW_USEDEFAULT, CW_USEDEFAULT,
hDlg, NULL,
g_hInst, NULL);
if (!hwndTool || !hwndTip)
{
return (HWND)NULL;
}
// Associate the tooltip with the tool.
TOOLINFO toolInfo = { 0 };
toolInfo.cbSize = sizeof(toolInfo);
toolInfo.hwnd = hDlg;
toolInfo.uFlags = TTF_IDISHWND | TTF_SUBCLASS;
toolInfo.uId = (UINT_PTR)hwndTool;
toolInfo.lpszText = pszText;
SendMessage(hwndTip, TTM_ADDTOOL, 0, (LPARAM)&toolInfo);
return hwndTip;
}
The tooltip vanishes as soon as I move my mouse pointer.
My questions are:
Is tooltip is destroyed or is it just hidden ?
If it is hidden then how to destroy it and when?
Thanks.
It's been a while since I've done any WinAPI programming but if my memory serves me...
The call to CreateWindowEx passes the hDlg as the hWndParent parameter meaning the dialog window is now the parent of the tooltip.
From the MSDN documentation on the DestroyWindow function it says:
If the specified window is a parent or owner window, DestroyWindow automatically destroys the associated child or owned windows when it destroys the parent or owner window. The function first destroys child or owned windows, and then it destroys the parent or owner window.
So you can assume your tooltip window will be destroyed eventually. Be careful if you are calling CreateToolTip in response to every WM_HELP message as you will end up with a number of tooltip windows hanging around in memory until your dialog is closed and DestroyWindow is finally called.
As vz0 pointed out you could create the tooltip once, hang on to the window handle, then show the tooltip in response to the help message rather than creating it again.
In your comment to vz0's answer you said:
there are multiple ways in which a tooltip goes awya. example: mouse move, timeout etc.
All of those only result in the window being hidden so the handle to the tooltip is still valid and can be redisplayed using ShowWindow.
For every CreateWindowEx call you need a matching DestroyWindow call.
As an alternative, instead of creating and destroying the window every time you can use the ShowWindow call with SW_SHOW and SW_HIDE to show and hide the popup.
In my experience, I had to DestroyWindow() on the tooltip so an HFONT (font GDI resource) was properly released. There was a parent-child bond of the two windows at one time - but my system changes this at run-time and could be to blame. Probably no harm in doing it if your system generalizes it.