public function edit(){
    $article=D('article');
    if(IS_POST){
        $data['title']=I('title');
        $data['content']=I('content');
        $data['desc']=I('desc');
        $data['cateid']=I('cateid');
        $data['id']=I('id');
        if($_FILES['pic']['tmp_name']!=''){
            $upload = new \Think\Upload();// 实例化上传类
            $upload->maxSize   =     3145728 ;// 设置附件上传大小
            $upload->exts      =     array('jpg', 'gif', 'png', 'jpeg');// 设置附件上传类型
            $upload->savePath  =      './Public/Uploads/'; // 设置附件上传目录
            $upload->rootPath  =      './'; // 设置附件上传目录
            $info   =   $upload->uploadOne($_FILES['pic']);
            if(!$info){
                $this->error($upload->getError());
            }else{
               $data['pic']=$info['savepath'].$info['savename'];
            }
        }
        if($article->create($data)){
            $save=$article->save();
            if($save !== false){
                $this->success('修改文章成功！',U('lst'));
            }else{
                $this->error('修改文章失败！');
            }
        }else{
            $this->error($article->getError());
        }
 
        return;
    }
    $articles=$article->find(I('id'));
    $this->assign('articles',$articles);
    $cateres=D('cate')->select();
    $this->assign('cateres',$cateres);
    $this->display();
}

如果没有改任何内容，会返回0的，如果是0你提示“没有作任何修改”，大于0提示修改成功。