1. The window maximizes, minimizes the implementation
When we cannot maximize, minimize and recover buttons in the title bar, you need to implement these features in other places, you can add:
WINDOWPLACEMENT WNDPL;
Windowplacement * PWNDPL;
PWNDPL = & WNDPL;
GetWindowPlacement (PWNDPL);
PWNDPL-> showcmd = sw_showminmized; // Implement the window minimization
SetwindowPlacement (PWNDPL);
Where the getWindowplacement () function gets the structure variable pointer of the Structure WindowPlacement of the current window layout, the structure of Windowplacement is defined as:
Typedef struct tagwindowplacement {
Uint Length;
Uint flags;
Uint showcmd;
Point PtminPosition;
Point ptmaxposition;
Rect rcNORMALPSITION;
WINDOWPLACEMENT;
The member variable showcmd determines the state of the current window, and the value is generally:
· SW_HIDE: Hide Window
· SW_MINIMIZE: Minimize the specified window
· SW_RESTORE: Restore the original size
· SW_SHOW: Activated and displayed in the original size
· SW_SHOWMAXIMIZED: Activate and maximize windows
The setWindowPlacement () function is to display the window according to the settings of WindowPlacement.
2. Why use a getsafehwnd () function
When we want to get a window object (CWnd derived object) pointer's handle (HWnd), the safest way is to use the getsafehwnd () function, to see the reason by the following example:
CWND * PWND = FindWindow ("ExplorewClass", NULL; // I hope to find the resource manager
HWND HWND = PWND-> m_hwnd; // Get it HWnd
This code will appear "General Protection Error" when the PWND started is empty, and closes the application because it is generally not accessing a NULL pointer, if using the following code:
CWND * PWND = FindWindow ("ExplorewClass", NULL; // I hope to find the resource manager
HWND HWND = PWND-> getsafehwnd (); // Get it HWnd
There will be no problem, because although when the PWND is NULL, getSafehWnd is still available, just returns NULL, and cleares the code through getSafehWnd (). Clear:
_AFXWIN_INLINE HWND CWND :: GetsafehWnd () Const
{
Return this == NULL? NULL: M_HWND;
}
3. How to make the program in a very small state
If we don't want the program's window to be seen by others, you can keep it in a very small state: When the recovery program window, Window sends a WM_QUERYOPEN message as long as false is returned in its message handler.
Bool cmainframe :: ONQUERYOPEN ()
{
Return False;
}
4. How to prohibit and use the shutdown button
CMenu * pmenu = AFXGETMAINWND () -> GetSystemMenu (false);
IF (PMenu)
{
PMenu-> EnableMenuItem (sc_close, mf_bycommand | mf_grayed);
}
Simply change MF_GRAYED to MF_ENABLED when recovering
5. How to delay in the program
method one:
Use the SLEEP function, such as delay 2 seconds, with SLEEP (2000);
Method Two:
Using the SLEEP function is unfavorable when delayed periods cannot handle other messages, if time is too long, it is like a crash, which does not have such problems with the COLEDATETIME class and the COLEDATETIMESPAN class:
COLEDATETIME Start_time = COLEDATETIME :: getcurrenttime ();
COLEDATETIMESPAN END_TIME = COLEDATETIME :: getcurrenttime () - start_time;
While (end_time.gettotalseconds () <= 2)
{
MSG msg;
GetMessage (& MSG, NULL, 0, 0);
PretranslateMessage (& MSG);
End_time = COLEDATETIME :: getcurrenttime-start_time;
}
In this way, we can also handle other messages when delayed.
I have seen some summary articles in the forum very well. I have written a little out of it. I don't know if there is any repetition. I hope I can have some micro role.
