xamarin android: showing ads in recycleview hide some articles in rss entries

I'm trying to show ads in recycleview and i succeeded to do it using the code below .. the problem is that in every "MspaceBetweenAds" position the ad show up but the article at this replaced with the ad i tried to fix it by modifying ItemCount() by Mposts.Count + (Mposts.count% MspaceBetweenAds) but i'm getting "IndexOutOfBounds " error any help please .. this is my code

public class AdsView : ListViewHolder
        {
            public AdView mAdView { get; private set; }
            public AdsView(View view) : base(view)
            {
               mAdView = view.FindViewById<AdView>(Resource.Id.AdsCard);
            }
        }

 public override RecyclerView.ViewHolder OnCreateViewHolder(ViewGroup parent, int viewType)
        {
            RecyclerView.ViewHolder vh = null;
            switch (viewType)
            {
                case 1:
                    View vBig = LayoutInflater.From(parent.Context).Inflate(Resource.Layout.BigCard, parent, false);
                    vh = new MyView(vBig);
                    break;
                case 2:                  
                    View vAds = LayoutInflater.From(parent.Context).Inflate(Resource.Layout.AdsCard, parent, false);
                    vh = new AdsView(vAds);
                    break;
            }
            return vh;
        } 
 public override void OnBindListViewHolder(ListViewHolder holder, int position)
        {
            var MyHolder = holder as MyView;
            switch (holder.ItemViewType)
            {
                case 1:
                    // code to show posts articles here
                    break;
                case 2:                 
                    var AdHolder = holder as AdsView;
                    fnc.AddBannerAd(AdHolder.mAdView);
                    break;
            }
        }
public override int GetItemViewType(int position)
        {
            if (position > 0 && position % mSpaceBetweenAds  == 0) { return 2; }
            else { return 1; }
        }

and this is a demo app https://drive.google.com/open?id=1Tk3G8dw9nqIffxmEFNGqIgXNzCJJPxD_

As the demo you posted contains 3rd party package, I cannot run it directly and modify the demo for you. The flowing is my solution to your problem:

Error causes: The way you do (modifying ItemCount() by Mposts.Count + (Mposts.count% MspaceBetweenAds) cannot change the real length of Mposts, as a result, it results in the "IndexOutOfBounds " error.

Solution If you want to insert ads into your recylerview, you need not only modify your adapter to show both item and ads, but also need to modify your layout resource file, that is, you need to insert the ads data into the data list for of your recylerview. Or you can simply add a duplicated item to the list every [MspaceBetweenAds]items.