How do I get the CDC of the modal dialog under MFC?

How can I use getdlgitem and getdc before the dialog box is created?

Who said that the text displayed by the static control cannot be dynamically refreshed, modify the id number of the static control, as long as it is not IDC static, you can use setdlgitemtext to dynamically update it, provided that it is displayed in the dialog box.

The first one you do: your is p=null;

Of course you can't go to p->getdc();

My thoughts in No. 2.

Mine is this kind of learning;

c***dlg* dlg=new c***dlg();Modal dialogs.

dlg->showwindow(sw_show);

dlg->upwindow();

cdc* pdc=dlg->getdc();

Set a member variable flag bit in c to determine whether it is a or b, such as int flag;

a, ccdlg dlg;;;

bWhen called, ccdlg dlg;;;

You do this by adding a flag to the category C:

class c

Then whether it's a or b, do it when domodal out of the c dialog;

true or false");It can be set to true for a and false for b.

afxgetmainwnd, but note that you can't access interface-related content, such as control variables in the main window.

cmainframe *)afxgetmainwnd()) variable name;

Get the handle to get the form via findwindow and then sendmessage closes!

There are many ways to do this: 1. overload onok(), 2. postmessage(window handle, wm close); 3. Call enddialog

Postmessage or SendMessage sends a message to the dialog box.

You describe that there is a problem. What you want to get is the pixel of the desktop.

cwnd* desk = getdesktopwindow();

cdc* pdc = desk->getdc();

colorref cr = pdc->getpixel(30,30);

desk->releasedc(pdc);I guess you forgot about that.

The modal dialog cannot execute the following statement without returning, so if lz does not need to use the modal dialog, you can use the ideasoft method, and if you insist on using the modal dialog, you can overload the oncreate function in the dialog class to complete the relevant functions.

In general, non-modal is used, but if you have to use modal, you can use what IdealSoft says, set a variable in the DLG to hold the function pointer (or save the pointer of the instance if you want to call the method of an instance of a class).

PS: I do this a lot, but it's a serious undermine of the aesthetics of C++ programs.

csheetdiadlg dlg;

m_pmainwnd = &dlg;

int_ptr nresponse = ;

if (nresponse == idok)else if (nresponse == idcancel)Here you can see the ** displayed in the main dialog, you will write a non-modal dialog, naturally you know how to change it.

But I look at your needs, this method is not good, look at MFC's cpropertysheet and cpropertypage classes, maybe you will find a better way, reference.