Subclassing

[johncp]

Folks

I want to implement my own pop up menu box when the user right clicks the task bar at the top of a window, ie I want the windows of my app. to show my dialog box instead of the standard useless MS box showing the restore/move/minimise/maximise/close dialog.

I've looked at TPopupMenu and TForm::OnContextPopup() but these only fire when clicking in the client area, not the task bar.

Is subclassing the solution ?

I'm new to subclassing & haven't googled much stuff relevant to CBuilder. Best so far might be Butthead's post (31/7/05) here on TTs.

Don't spend time on this but if you already have the URL of a good subclassing tut./example then pls post it.

John

 

[2ffat]

See if any of these articles help:
Custom open dialogs, part I
Custom Open dialogs, part II
Extending the common dialogs

BTW, C++Builder Developer's Journal is a great mag, IMHO.

James P. Cottingham
^{I'm number 1,229!
I'm number 1,229!}

 

[johncp]

Hi James

Thanx for the links. Yes the C++ Dev. journal looks good. I've downloaded & am digesting "Extending the common dialogs" which is subscription free & shows subclassing.

John

 

[johncp]

James

After many problems, and the aid of Petzold's book "Programming Windows" which I came across on the net in pdf form - and which I think is a free download from his site - I arrived at a simple solution. The following adds 2 items to the system menu in positions 5 & 6 of Form9 and toggles the check mark against them. Thanks for your help.

//handler calls WndProc to insert menu item
void __fastcall TForm9::OnCreateWindow(TObject *Sender)
{
TMessage* Message ;
HWND WinHandle = Form9->Handle ;
HMENU MenuHandle = GetSystemMenu(WinHandle, false);

InsertMenu(MenuHandle, 5, MF_BYPOSITION | MF_CHECKED, 8, "Dock"); //or WM_APP+8 ?
InsertMenu(MenuHandle, 6, MF_BYPOSITION | MF_CHECKED, 9, "Stay On Top");
TForm:ispatch(&Message) ;
}
//---------------------------------------------------------------------------
void __fastcall TForm9::WndProc(TMessage& Message)
{
HWND WinHandle = Form9->Handle ;
HMENU MenuHandle = GetSystemMenu(WinHandle, false);

//switch(Message.Msg) //only works for bugs in client areas
switch(Message.WParam) //system menu handle
{
case 8 :
if(GetMenuState(MenuHandle, 8, MF_BYCOMMAND)==MF_CHECKED)
ModifyMenu(MenuHandle, 5, MF_BYPOSITION | MF_STRING | MF_UNCHECKED, 8, "Dock") ; //MUST include MF_BYPOSITION
else
ModifyMenu(MenuHandle, 5, MF_BYPOSITION | MF_STRING | MF_CHECKED, 8, "Dock") ;
break ;
case 9 :
if(GetMenuState(MenuHandle, 9, MF_BYCOMMAND)==MF_CHECKED)
ModifyMenu(MenuHandle, 6, MF_BYPOSITION | MF_STRING | MF_UNCHECKED, 9, "Stay on Top") ;
else
ModifyMenu(MenuHandle, 6, MF_BYPOSITION | MF_STRING | MF_CHECKED, 9, "Stay on Top") ;
break ;
default : ;
}
TForm::WndProc(Message);
}