MFC obtains the main window and parent window pointer

In MFC programming, parameters are often transferred from the Child Window to the parent window, which requires the pointer of the parent window.

For example, in the main dialog box, cmymaindlg uses the button buttona to enter the cmyparentdlg, and cmyparentdlg uses the button buttonb to enter the cmychilddlg. To access the contents of cmyparentdlg and cmymaindlg in cmychilddlg, add the following two statements to cmychilddlg:

Cmymaindlg * pmmd = (cmymaindlg *) afxgetmainwnd (); // obtain the main window pointer
Cmyparentdlg * pmpd = (cmyparentdlg *) This-> getparent (); // obtain the parent window pointer

Here, this indicates the current window pointer, pointing to cmychilddlg; pmmd and pmpd are pointers to the main window and parent window.