public override void OnBindViewHolder(RecyclerView.ViewHolder holder, int position)
 {
     vh = holder as FileViewHolder;
     if (FileTitleList != null)
     {
         vh.Caption.Text = FileTitleList[position];
     }
 }
            public override RecyclerView.ViewHolder OnCreateViewHolder(ViewGroup parent, int viewType)
            {
                View itemView = LayoutInflater.From(parent.Context).
                                Inflate(Resource.Layout.FileCardView, parent, false);
                CardView cv = itemView.FindViewById <CardView>(Resource.Id.fileCardView);

                cv.SetBackgroundColor(_darkGrey);
                vh = new FileViewHolder(itemView, OnClick);

                return(vh);
            }