private ImageViewPlus iv_roundRect;//圆角矩形图片
        protected override void OnCreate(Bundle savedInstanceState)
        {
            base.OnCreate(savedInstanceState);

            // Create your application here
            SetContentView(Resource.Layout.main_content_item);
            iv_roundRect = FindViewById <ImageViewPlus>(Resource.Id.roundRect);
            iv_roundRect.SetType(ImageViewPlus.TYPE_ROUND);
            iv_roundRect.SetRoundRadius(120);
        }
        public MainItemAdapterViewHolder(View itemView, Action <MainItemAdapterClickEventArgs> clickListener,
                                         Action <MainItemAdapterClickEventArgs> longClickListener) : base(itemView)
        {
            _v_title   = (TextView)itemView.FindViewById(Resource.Id.v_title);
            _v_time    = itemView.FindViewById <TextView>(Resource.Id.v_time);
            _v_comment = itemView.FindViewById <TextView>(Resource.Id.v_commont);
            _v_collect = itemView.FindViewById <TextView>(Resource.Id.v_collect);
            imagePlus  = itemView.FindViewById <ImageViewPlus>(Resource.Id.roundRect);
            imagePlus.SetType(ImageViewPlus.TYPE_ROUND);
            imagePlus.SetRoundRadius(120);

            itemView.Click += (sender, e) => clickListener(new MainItemAdapterClickEventArgs
            {
                View     = itemView,
                Position = AdapterPosition
            });
            itemView.LongClick += (sender, e) => longClickListener(new MainItemAdapterClickEventArgs {
                View = itemView, Position = AdapterPosition
            });
        }