编译过程中经常提示出错

各位前辈，我是初学者，在编译过程中经常出现以下错误，我知道出错的意思，就是不知道如何去修改，请各位指点迷津，万分感谢！！！
--------------------Configuration: Hello World - Win32 Debug--------------------
Compiling...
MainFrm.cpp
C:\Program Files\Microsoft Visual Studio\MyProjects\Hello World\MainFrm.cpp(49) : error C2509: 'OnCreate' : member function not declared in 'CMainFrame'
        c:\program files\microsoft visual studio\myprojects\hello world\mainfrm.h(13) : see declaration of 'CMainFrame'
C:\Program Files\Microsoft Visual Studio\MyProjects\Hello World\MainFrm.cpp(79) : error C2509: 'PreCreateWindow' : member function not declared in 'CMainFrame'
        c:\program files\microsoft visual studio\myprojects\hello world\mainfrm.h(13) : see declaration of 'CMainFrame'
Error executing cl.exe.

Hello World.exe - 2 error(s), 0 warning(s)