Summary of dialog box Hiding Methods

In the process of program development, many applications need to be moved together to hide them. These programs run mostly as backend programs. To avoid affecting other windows, only one icon is displayed in the tray area. The following methods can be implemented.

1. Timer

The most intuitive and helpless way is to use a timer. Since showwindow (sw_hide) cannot be used to hide it before the dialog box starts to display it, you can give it a time to show it. When it is finished, we can hide it. The method is as follows:

1. Set the timer in the oninitdialog () function: (settimer (1, 1, null) in the Windows API Response Message wm_initdialog );

2. Add the message processing function ontimer for processing wm_timer and add the Code:

If (nidevent = 1)

{

Killtimer (1 );

Showwindow (sw_hide );

}

The disadvantage of this method is that it makes the stability of the program seem to be a discount; the window needs to be displayed first, so the effect is that the window disappears.

2. Change the dialog box display status

You can hide a dialog box by changing its display attribute during initialization. The method is to call the setwindowplacement function:

Bool cdialogexdlg: oninitdialog ()

{

Cdialog: oninitdialog ();

// Do something

Windowplacement WP;

WP. Length = sizeof (windowplacement );

WP. Flags = wpf_restoretomaximized;

WP. showcmd = sw_hide;

Setwindowplacement (& WP );

Return true;

}

When you need to display it (usually the mouse message that responds to the hot key or tray icon ):

Windowplacement WP;

WP. Length = sizeof (windowplacement );

WP. Flags = wpf_restoretomaximized;

WP. showcmd = sw_show;

 

Setwindowplacement (& WP );

This effect is not ideal: the window is displayed in the upper left corner of the screen and only has a title bar. to display the window normally, add the following code: Define a member variable crect rect; In oninitdialog () inside:

Getwindowrect (& rect );

In the desired area:

Setwindowpos (& wndnotopmost, wndrc. Left, wndrc. Top, wndrc. Right, wndrc. Bottom, swp_showwindow );

Centerwindow ();

Even so, the effect is still poor. Another drawback of this method is that when the program starts to run and is hidden, the original activated window becomes inactive, and after the dialog box is displayed, the dialog box itself is also inactive.

 3. Do not draw a window

When the dialog box is displayed, the message wm_paint will be returned to draw the customer area, and the corresponding message wm_ncpaint will draw the window border. We can hide the window when the window is self-painted for the first time, and we can enjoy good results. Since the window draws the window border first, we only need to process wm_ncpaint. The Code is as follows:

Add the wm_ncpaint handler.

Void cmydialog: onncpaint ()

{

Static int I = 2;

If (I> 0)

{

I --;

Showwindow (sw_hide );

}

Else

Cdialog: onncpaint ();

}

Here is a question: why do I need to define static variable I and set its value to 2?

As long as the window is hidden for the first time, we can define this variable to determine whether to display the window for the first time. When the program starts to run, the system sends the (sendmessage) wm_ncpaint message. The window border of the program should be displayed, but we did not perform any display operations, but hidden the window, showwindow (sw_hide) will remove the ws_visible attribute of the window and continue the execution. The program will check the ws_visible attribute. If not, the window will be displayed, so a wm_ncpaint message is sent. So we need to process the wm_ncpaint message twice.

Call showwindow (sw_show) when you need to display the window.

The execution result of the program is that the window in the activation status may flash twice and remain in the activation status. This processing method is much better than the above method.

4. Use the dialog box as a subwindow.

This method uses the SDI framework. The main window is always hidden. the dialog box is used as a member variable of the main window. Add the following code in cmainframe: oncreate:

If (! DLG. Create (idd_mydialog, this ))

 

{

Return-1;

}

DLG. showwindow (sw_hide );

Use DLG. showwindow (sw_show); to display the dialog box. Note that the main window must be hidden; otherwise, the dialog box may flash.

Hide the status bar window:

The methods for checking the dialog box are described above. If you have tried it, you may have noticed that the icon of the program will flash when the program starts in the system status bar, this is also to be hidden when hiding the dialog box. The method is simple:

Add modifystyleex (ws_ex_appwindow, ws_ex_toolwindow); To the oninitdialog () function. Add the code modifystyleex (ws_ex_toolwindow, ws_ex_appwindow) to the window to be displayed, and change the extended window style back.