MFC "static_cast": Cannot convert from "void (__thiscall Cchatdlg::*) (Wparam,lparam)" to "LRESULT (__thiscall CWnd::*) (Wparam,lparam)"

Compile error prompt:

Error C2440: "static_cast": Cannot convert from "void (__thiscall Cchatdlg::*) (Wparam,lparam)" to "LRESULT (__thiscall CWnd::*) (WPARAM, LPARAM) "
1> a cast from a base type to a derived type requires dynamic_cast or static_cast

To change the definition:
afx_msg void onrecvdata (WPARAM WPARAM, LPARAM LPARAM);
For
afx_msg LRESULT onrecvdata (WPARAM WPARAM, LPARAM LPARAM);

Compiled by

LRESULT is a data type,
Msdn:32-bit value returned from a window procedure or callback function
Refers to a 32-bit value returned from a window program or callback function.

MFC "static_cast": Cannot convert from "void (__thiscall Cchatdlg::*) (Wparam,lparam)" to "LRESULT (__thiscall CWnd::*) (Wparam,lparam)"