I have to change the button text/size of a standard MessageBox in Windows (Win 7 actually). I'm coding in C++/CLI so the only way to show such a window is to do System::Windows::Forms::MessageBox::Show(...). I can modify the button by hooking a function to WH_CBT and getting the code HCBT_ACTIVATE...
So far so good. Now I want to resize the window itself to fit the buttons. I get the code HCBT_CREATEWND and I modify the struct CBT_CREATEWND (member cx for the width, etc.) And it works...
But it appears that the MessageBox buttons are drawn over a gray rectangle that spans the whole window width. This rectangle is not a window (using Spy++) but probably a draw done with FillRectangle() or something equivalent. And unfortunately my procedure won't allow to redraw it. In other words, if I widen the MessageBox, the gray rectangle under the buttons is not redrawn.
Here is my (oversimplified) function:
// Simplified code...
#define NEW_WIDTH 300
LRESULT CALLBACK CBTProc( int code, WPARAM wParam, LPARAM lParam )
{
HWND hwnd = (HWND)wParam;
switch ( code )
{
case HCBT_ACTIVATE:
// Change buttons here
return 0;
case HCBT_CREATEWND:
// Change window size here
LPCBT_CREATEWND cw = (LPCBT_CREATEWND)lParam;
if ( 'Main MessageBox Window, don't worry it works fine' )
{
cw.cx = NEW_WIDTH;
return 0;
}
}
}
return CallNextHookEx( hook, code, wParam, lParam );
}
So my question is quite simple: how, using the hook mechanism, can I force the MessageBox to draw the gray rectangle under the buttons correctly when it is resized by a hook function?
Related
I want to find all the top-level windows (children of the desktop) beneath a given point on the desktop. I can't find an API for this.
My scenario is that I'm dragging a window across the screen and want to drop it into another (known) window. I can hit test the bounds of the target window ok, but that doesn't tell me whether it's occluded by another (unknown) window. Using WindowFromPoint and friends won't work, because the window being dragged is necessarily directly under the mouse. So I'm wondering if I can obtain all windows at the mouse position, and review them to see whether one of the windows I'm tracking is directly beneath the window I'm dragging.
Is there a way to do this without resorting to EnumDesktopWindows/GetWindowRect on every mouse drag? Or perhaps there's another solution I'm missing.
If you ask kindly, WindowFromPoint will ignore your window (the one currently being dragged) and return the next window. This is what Internet Explorer does when you drag a tab.
To do that:
Handle WM_NCHITTEST in window being dragged
Return HTTRANSPARENT during dragging. Call default window proc otherwise.
WindowFromPoint will ignore HTTRANSPARENT windows, but only those belonging to the calling thread. This shouldn't be a problem for you, because you should be calling WindowFromPoint from the window owner thread anyway.
Make sure there're no child windows at point passed to WindowFromPoint, or handle WM_NCHITTEST for these child windows as well.
Troubleshooting (if you still get your window from WindowFromPoint)
Test GetCurrentThreadID() == GetWindowThreadProcessId(WindowFromPoint(), 0) to ensure you're calling from correct thread
In WM_NCHITTEST, test that hwnd parameter equals what you get from WindowFromPoint()
Example (the area within rectangle returns the underlying window from WindowFromPoint):
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
static const RECT s_TransparentRect = {100, 100, 200, 200};
switch (message)
{
case WM_NCCREATE:
SetTimer(hWnd, 1, 100, 0);
break;
case WM_TIMER:
{
POINT cursorPos;
GetCursorPos(&cursorPos);
TCHAR buffer[256];
_snwprintf_s(buffer, _countof(buffer), _TRUNCATE, _T("WindowFromPoint: %08X\n"), (int)WindowFromPoint(cursorPos));
SetWindowText(hWnd, buffer);
}
break;
case WM_PAINT:
{
PAINTSTRUCT ps;
BeginPaint(hWnd, &ps);
Rectangle(ps.hdc, s_TransparentRect.left, s_TransparentRect.top, s_TransparentRect.right, s_TransparentRect.bottom);
EndPaint(hWnd, &ps);
}
break;
case WM_NCHITTEST:
{
POINT cursorPos;
GetCursorPos(&cursorPos);
MapWindowPoints(HWND_DESKTOP, hWnd, &cursorPos, 1);
if (PtInRect(&s_TransparentRect, cursorPos))
return HTTRANSPARENT;
}
break;
}
return DefWindowProc(hWnd, message, wParam, lParam);
}
Right, you already know what WindowFromPoint() is going to return, should be the one you are dragging. Then use GetWindow() with uCmd = GW_HWNDNEXT to get the one below it in the Z-order. GetWindowRect() to get its bounds, IntersectRect() to compute the overlap.
Keep calling GetWindow() to find more windows that might be overlapped. Until it returns NULL or the overlap is good enough. If not then you'll normally favor the one that has the largest result rectangle from IntersectRect().
I'm using checkbox buttons and I want to make the button expand in width when I click it using LBUTTONDOWN
Would this involve using something like AppendMenu()? If so, how would I do it?
This is what I have so far for my button proc:
LRESULT CALLBACK ButtonWndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam){
static int x,y,btnwidth, btnheight;
switch (message){
case WM_USER:
btnwidth=wParam;
btnheight=lParam;
return 0;
case WM_LBUTTONDOWN:
btnwidth *= 2;
break;
}
You can expand the button by calling MoveWindow. You probably will want to first call GetWindowRect to get the current size and position, and then ScreenToClient to convert the rect to client coordinates. Then you can adjust the client coordinates as you wish and pass them to MoveWindow.
I am trying to send some simple mouse down/up messages to Windows Calculator using SendMessage. I have been able to press the buttons by sending the messages to the buttons directly. However, I have not been able to successfully send the same messages to the main calculator window handle. Given that hWnd is the window handle to calculator, this is my code.
IntPtr fiveKey = FindWindowEx(hWnd, IntPtr.Zero, "Button", "5");
int x = 5; // X coordinate of the click
int y = 5; // Y coordinate of the click
IntPtr lParam = (IntPtr)((y << 16) | x); // The coordinates
IntPtr wParam = IntPtr.Zero; // Additional parameters for the click (e.g. Ctrl)
const uint downCode = 0x201; // Left click down code
const uint upCode = 0x202; // Left click up code
SendMessage(fiveKey, downCode, wParam, lParam); // Mouse button down
SendMessage(fiveKey, upCode, wParam, lParam); // Mouse button up
Can anyone explain to me why sending the messages to hWnd instead of fiveKey with the x/y offsets changed to the position of the "5" key does not work? I would like to eventually use this code to simulate mouse clicks on a different application that doesn't have buttons like calculator.
I'm not sure I follow you. Are you trying to send WM_LBUTTONDOWN to the main window with the coordinates of where the 5 button is, with the hopes that the 5 button will get "clicked"? If so, that's just not going to work. WM_LBUTTONDOWN is only ever sent to the window under the mouse cursor. In theory the main window could handle WM_LBUTTONDOWN and see if any of its child windows are at that location, but nobody does that because that's not how WM_LBUTTONDOWN is designed to work.
Note: code samples have been simplified, but the overall structure remains intact.
I am working on a Win32 application whose main interface is a system tray icon. I create a dummy window, using HWND_MESSAGE as its parent, to receive the icon's messages:
WNDCLASSEX wndClass;
wndClass.lpfnWndProc = &iconWindowProc;
// ...
iconWindowHandle = CreateWindow(wndClass.lpszClassName, _T(""), 0, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, HWND_MESSAGE, NULL, GetModuleHandle(NULL), 0);
Then the icon is created, referring to this message-only window:
NOTIFYICONDATA iconData;
iconData.hWnd = iconWindowHandle;
iconData.uCallbackMessage = TRAYICON_MESSAGE;
// ...
Shell_NotifyIcon(NIM_ADD, &iconData)
When the tray icon is double-clicked, I create and show a property sheet (from comctl32.dll):
LRESULT CALLBACK iconWindowProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam) {
switch (uMsg) {
case TRAYICON_MESSAGE:
switch (lParam) { // that contains the "real" message
case WM_LBUTTONDBLCLK:
showPropertySheet();
return 0;
// ...
}
break;
// ...
}
return DefWindowProc(hWnd, uMsg, wParam, lParam);
}
The property sheet has no parent window. The PropertySheet function is called from the window procedure of the message-only window. The PSH_MODELESS flag is not set; thus, PropertySheet only returns after the property sheet window is closed again:
void showPropertySheet() {
PROPSHEETPAGE pages[NUM_PAGES];
pages[0].pfnDlgProc = &firstPageDialogProc;
// ...
PROPSHEETHEADER header;
header.hwndParent = NULL;
header.dwFlags = PSH_PROPSHEETPAGE | PSH_USECALLBACK;
header.ppsp = pages;
// ...
PropertySheet(&header);
}
Now all this works just fine, until I set a breakpoint inside the dialog procedure of one of the property sheet's pages:
BOOL CALLBACK firstPageDialogProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam) {
return FALSE; // breakpoint here
}
When the program stops on the breakpoint, the entire taskbar locks up!
The call stack is quite useless; it shows that the dialog procedure is called from somewhere inside comctl32.dll, via some calls inside user32.dll. No window procedure of my own is in between.
Making the property sheet modeless doesn't seem to help. Also, I'd rather not do this because it makes the code more complex.
As long as my dialog procedure returns quickly enough, this shouldn't be a problem. But it seems so weird that a longer operation inside the dialog procedure would not only lock up the dialog itself, but the entire shell. I can imagine that the message-only window procedure has the power to cause this behaviour, since it's more closely related to the tray icon... but this function is not shown on the call stack.
Am I doing something fundamentally wrong? Can anyone shed some light on this issue?
Actually, it's rather obvious, and the confusion must have been due to a lack of coffee.
The taskbar probably uses SendMessage to send the message to my application, which causes it to block until the message is handled. SendMessageTimeout is apparently not used.
I still think it's strange that no function of my own shows up on the call stack. Surely, such a message must flow through my message loop in order to be processed? Maybe the warning that "stack frames below this line may be incomplete or missing" was actually right, then.
I want to create an array of 256 colored buttons with the owner draw extended style to a dialog box created with the visual studio dialog design tool. I added a loop to the WM_INITDIALOG message handler in the dialog procedure to do this:
for (i=0; i<=255; i++)
{
int xp, yp;
HWND status;
xp = rect_pos.left+16*(i%16);
yp = rect_pos.top+16*(i>>4);
status = CreateWindow (
TEXT("button"),
"\0",
WS_CHILD|WS_VISIBLE|BS_OWNERDRAW|BS_PUSHBUTTON,
xp,
yp,
15,
15,
hDlg,
(HMENU) 5000+i, // id used to report events
hInst,
NULL
);
if (status == NULL)
xp =7;
}
I added a message handler for the WM_CTLCOLORBTN message.
case WM_CTLCOLORBTN:
{
int zz;
zz = GetWindowLong ((HWND) lParam, GWL_ID); // window identifier
zz -= 5000;
if ((zz >= 0) && (zz <= 255))
{
HBRUSH BS;
SetTextColor ((HDC) wParam, Collector.Color);
SetBkColor ((HDC) wParam, Collector.Color);
return ((LRESULT) Collector.Brush);
}
break;
}
It more or less works but only the first 64 buttons are displayed. I intend to use a different brush to color each button but for debug puproses, I substituted a single well defined brush. I've debugged the code and satisfied myself the x/y coordinates are proper for each button and that the ID provided in the hMenu createwindow call is proper. I watched all 256 buttons get colored in the WM_CTLCOLORBTN handler. I included a check to make sure the createwindow call does not return failure (NULL). I can get either 4 rows of 16 buttons or 4 columns of 16 buttons by interchanging the x/y parameters on the createwindow call.
If I remove the BS_OWNERDRAW bit from the createwindow call, all 256 buttons are drawn.
It's as if there a limit of 64 buttons with BS_OWNERDRAW :-(
Any help would be greatly appreciated!
TIA, Mike
Are you handling the WM_DRAWITEM message in conjunction with the BS_OWNERDRAW style?
In your case, it seems surprising to me that any buttons are displayed while using the BS_OWNERDRAW style, while BS_PUSHBUTTON is set.
As mentioned in the following link to the documentation for BS_OWNERDRAW, you need to handle WM_DRAWITEM and avoid specifying any other BS_ button styles.
Button Styles from MSDN
Also curious is that the WM_CTLCOLORBUTTON message may be received and then ignored for buttons containing the BS_PUSHBUTTON style. Check out the following link for the documentation on that window message.
WM_CTLCOLORBUTTON from MSDN
From what I can see in your code snippet, most likely you will want to do the following:
Set BS_OWNERDRAW when creating the child buttons.
Handle WM_DRAWITEM on the dialog and draw the button in its correct state. Note that you don't have to handle WM_CTLCOLORBUTTON, just use the Brushes and Fonts and modify the DC as you wish inside your WM_DRAWITEM handler.
Also, depending on your application, you might benefit from making your own window class to represent a grid of buttons on your own, and just drawing the items to taste. This is preferable if you're just displaying internal state and not really looking for the user to manage or interact with a grid of buttons.
Thanks to all who gave advice and help. I now have this working to my satisfaction. I have successfully colored the buttons and surrounded them with a black outline if selected or if they have the input focus. I'll add some code snippets below to show the final state of things but here is synopsis. First, I believe there is some legacy code in my system which makes owner drawn buttons respond to the WM_CTLCOLORBTN for the first child 64 buttons created. Second, I believe the only thing one needs to do is create the buttons, respond properly to the WM_DRAWITEM and WM_COMMAND/BN_CLICKED messages.
Here are the code snippets from my dialog box handler.
In the WM_INITDIALOG code -- create the buttons
for (i=0; i<=255; i++)
{
int xp, yp;
HWND status;
xp = rect_pos.left+16*(i&0x0F);
yp = rect_pos.top+16*(i>>4);
status = CreateWindow
(
TEXT("button"),
"\0",
WS_CHILD|WS_VISIBLE|WS_TABSTOP|BS_OWNERDRAW,
xp,
yp,
15,
15,
hDlg,
(HMENU) (5000+i), // id used to report events
hInst,
NULL
);
if (status == NULL)
xp =7;
SetFocus (status);
}
Respond to the WM_DRAWITEM message
case WM_DRAWITEM: // Owner drawn botton
{
LPDRAWITEMSTRUCT lpDrawItem;
HBRUSH BS, BS_Old;
HPEN PN_Old;
int sz=15;
int cntl;
cntl = LOWORD (wParam) - 5000;
lpDrawItem = (LPDRAWITEMSTRUCT) lParam;
if (lpDrawItem->CtlType != ODT_BUTTON)
return FALSE;
BS = CreateSolidBrush (ColorRef[cntl]);
if (lpDrawItem->itemState & (ODS_SELECTED | ODS_FOCUS))
{
sz = 14;
PN_Old = (HPEN) SelectObject(lpDrawItem->hDC, GetStockObject(BLACK_PEN));
}
else
PN_Old = (HPEN) SelectObject(lpDrawItem->hDC, GetStockObject(NULL_PEN));
BS_Old = (HBRUSH) SelectObject(lpDrawItem->hDC, BS);
Rectangle (lpDrawItem->hDC, 0, 0, sz, sz);
SelectObject(lpDrawItem->hDC, PN_Old);
SelectObject(lpDrawItem->hDC, BS_Old);
DeleteObject (BS);
return true;
}
and finally in the WM_COMMAND code
if (HIWORD(wParam) == BN_CLICKED)
{
if ((LOWORD(wParam) >= 5000) && (LOWORD(wParam) <=5255))
{
Color[0] = ColorRef[LOWORD(wParam)-5000] & 0xFF;
Color[1] = (ColorRef[LOWORD(wParam)-5000] >> 16) & 0xFF;
Color[2] = (ColorRef[LOWORD(wParam)-5000] >> 8 ) & 0xFF;
InvalidateRect (hDlg, NULL, TRUE);
goto Set_Color;
}
}