CListBox的CBN_SELCHANGE CCOMboBox的LBN_SELCHANGE

LRESULT CALLBACK WindowProc(
  HWND hwnd,       // handle to window
  UINT uMsg,       // WM_COMMAND
  WPARAM wParam,   // combo box identifier, CBN_SELCHANGE
  LPARAM lParam    // handle to combo box (HWND)
);

The CBN_SELCHANGE notification message is sent when the user changes the current selection in the list box of a combo box

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LRESULT CALLBACK WindowProc(
  HWND hwnd,       // handle to window
  UINT uMsg,       // WM_COMMAND
  WPARAM wParam,   // list box identifier, LBN_SELCHANGE
  LPARAM lParam    // handle to list box (HWND)
);

An application sends the LBN_SELCHANGE notification message when the selection in a list box is about to change.