already has a body?解决办法

already has a body?
void   CListTreeViewDlg::OnSelchangedTree(NMHDR*   pNMHDR,   LRESULT*   pResult)  
然后提醒我   function 'void_thiscall   CListTreeViewDlg::OnSelchangedTree(struct   tagNMHDR*,long*) 'already   has   a   body?
这是什么原因啊   我就是做一个简单的树而已....不会做   郁闷~~谢谢了哈~

[解决办法]
有两个实现？
搜索OnSelchangedTree