I recently ran into a problem using CodeIgniter where I kept receiving the error: “Call to a member function on a non-object”. This problem occurred when I was trying to use a method from one model from within another model.

I have a model named mGalleryImages. Within this model, I have a method named addGalleryImages. Within this method, I load another model and tried to call a method from the loaded model:

function addGalleryImages(){
     ...
     $this->load->model('mUtilImages');
     ...
     $this->mUtilImages->setImageFile($_FILES['uploadFile']);
}

I receive the error when the setImageFile method is called. The problem is that when the model sees “$this”, it is looking for a method within the mGalleryImages model. The solution was to use a CodeIgniter function named get_instance().

function addGalleryImages(){
     ...
     $CI =& get_instance();
     $this->load->model('mUtilImages');
     ...
     $CI->mUtilImages->setImageFile($_FILES['uploadFile']);
}

Easy enough, but I would never have thought that this was the problem. I played with this code for hours, trying to figure out why it didn’t work similarly to a regular PHP class. But now I know.