我使用的代码与您的代码不同，但是可以正常工作，而且很容易理解，首先将此功能放入模型文件中即可.

i have code that is different from yours but it works and also it is easy to understand first put this function in your model file

在模型文件中

function updatedata($tbname, $data, $parm)
    {
        return $this->db->update($tbname, $data, $parm);    
    }

在控制器文件中的用法如下

in your controller file use like this

  $this->load->model("Your_model_name");    
  $this->Your_model_name->updatedata('mytable',$data,$your_condition_in_array);

我希望这会有所帮助，我确信此代码可以正常工作，请让我知道此代码适合您.

i hope this will help, i am sure about that this code works, please let me know that this code is worked for you.