Как создать расширяемый RecyclerView в xamarin.android

Question

Я пытаюсь преобразовать приведенный ниже код Android (Java-адаптер) в xamarin.android (C #).

1. ExpandableRecyclerAdapter.java

public abstract class ExpandableRecyclerAdapter<T extends ExpandableRecyclerAdapter.ListItem> extends RecyclerView.Adapter<ExpandableRecyclerAdapter.ViewHolder> {
protected Context mContext;
protected List<T> allItems = new ArrayList<>();
protected List<T> visibleItems = new ArrayList<>();
private List<Integer> indexList = new ArrayList<>();
private SparseIntArray expandMap = new SparseIntArray();
private int mode;

protected static final int TYPE_HEADER = 1000;

private static final int ARROW_ROTATION_DURATION = 150;

public static final int MODE_NORMAL = 0;
public static final int MODE_ACCORDION = 1;

public ExpandableRecyclerAdapter(Context context) {
    mContext = context;
}

public static class ListItem {
    public int ItemType;

    public ListItem(int itemType) {
        ItemType = itemType;
    }
}

@Override
public long getItemId(int i) {
    return i;
}

@Override
public int getItemCount() {
    return visibleItems == null ? 0 : visibleItems.size();
}

protected View inflate(int resourceID, ViewGroup viewGroup) {
    return LayoutInflater.from(mContext).inflate(resourceID, viewGroup, false);
}

public class ViewHolder extends RecyclerView.ViewHolder {
    public ViewHolder(View view) {
        super(view);
    }
}

public class HeaderViewHolder extends ViewHolder {
    ImageView arrow;

    public HeaderViewHolder(View view, final ImageView arrow) {
        super(view);

        this.arrow = arrow;

        view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                handleClick();
            }
        });
    }

    protected void handleClick() {
        if (toggleExpandedItems(getLayoutPosition(), false)) {
            openArrow(arrow);
        } else {
            closeArrow(arrow);
        }
    }

    public void bind(int position) {
        arrow.setRotation(isExpanded(position) ? 90 : 0);
    }
}

public boolean toggleExpandedItems(int position, boolean notify) {
    if (isExpanded(position)) {
        collapseItems(position, notify);
        return false;
    } else {
        expandItems(position, notify);

        if (mode == MODE_ACCORDION) {
            collapseAllExcept(position);
        }

        return true;
    }
}

public void expandItems(int position, boolean notify) {
    int count = 0;
    int index = indexList.get(position);
    int insert = position;

    for (int i=index+1; i<allItems.size() && allItems.get(i).ItemType != TYPE_HEADER; i++) {
        insert++;
        count++;
        visibleItems.add(insert, allItems.get(i));
        indexList.add(insert, i);
    }

    notifyItemRangeInserted(position + 1, count);

    int allItemsPosition = indexList.get(position);
    expandMap.put(allItemsPosition, 1);

    if (notify) {
        notifyItemChanged(position);
    }
}

public void collapseItems(int position, boolean notify) {
    int count = 0;
    int index = indexList.get(position);

    for (int i=index+1; i<allItems.size() && allItems.get(i).ItemType != TYPE_HEADER; i++) {
        count++;
        visibleItems.remove(position + 1);
        indexList.remove(position + 1);
    }

    notifyItemRangeRemoved(position + 1, count);

    int allItemsPosition = indexList.get(position);
    expandMap.delete(allItemsPosition);

    if (notify) {
        notifyItemChanged(position);
    }
}

public class StaticViewHolder extends ViewHolder {
    public StaticViewHolder(View view) {
        super(view);
    }
}

public class ItemViewHolder extends ViewHolder {
    public ItemViewHolder(View view) {
        super(view);
    }
}

protected boolean isExpanded(int position) {
    int allItemsPosition = indexList.get(position);
    return expandMap.get(allItemsPosition, -1) >= 0;
}

@Override
public int getItemViewType(int position) {
    return visibleItems.get(position).ItemType;
}

public void setItems(List<T> items) {
    allItems = items;
    List<T> visibleItems = new ArrayList<>();
    expandMap.clear();
    indexList.clear();

    for (int i=0; i<items.size(); i++) {
        if (items.get(i).ItemType == TYPE_HEADER) {
            indexList.add(i);
            visibleItems.add(items.get(i));
        }
    }

    this.visibleItems = visibleItems;
    notifyDataSetChanged();
}

protected void notifyItemInserted(int allItemsPosition, int visiblePosition) {
    incrementIndexList(allItemsPosition, visiblePosition, 1);
    incrementExpandMapAfter(allItemsPosition, 1);

    if (visiblePosition >= 0) {
        notifyItemInserted(visiblePosition);
    }
}

protected void removeItemAt(int visiblePosition) {
    int allItemsPosition = indexList.get(visiblePosition);

    allItems.remove(allItemsPosition);
    visibleItems.remove(visiblePosition);

    incrementIndexList(allItemsPosition, visiblePosition, -1);
    incrementExpandMapAfter(allItemsPosition, -1);

    notifyItemRemoved(visiblePosition);
}

private void incrementExpandMapAfter(int position, int direction) {
    SparseIntArray newExpandMap = new SparseIntArray();

    for (int i=0; i<expandMap.size(); i++) {
        int index = expandMap.keyAt(i);
        newExpandMap.put(index < position ? index : index + direction, 1);
    }

    expandMap = newExpandMap;
}

private void incrementIndexList(int allItemsPosition, int visiblePosition, int direction) {
    List<Integer> newIndexList = new ArrayList<>();

    for (int i=0; i<indexList.size(); i++) {
        if (i == visiblePosition) {
            if (direction > 0) {
                newIndexList.add(allItemsPosition);
            }
        }

        int val = indexList.get(i);
        newIndexList.add(val < allItemsPosition ? val : val + direction);
    }

    indexList = newIndexList;
}

public void collapseAll() {
    collapseAllExcept(-1);
}

public void collapseAllExcept(int position) {
    for (int i=visibleItems.size()-1; i>=0; i--) {
        if (i != position && getItemViewType(i) == TYPE_HEADER) {
            if (isExpanded(i)) {
                collapseItems(i, true);
            }
        }
    }
}

public void expandAll() {
    for (int i=visibleItems.size()-1; i>=0; i--) {
        if (getItemViewType(i) == TYPE_HEADER) {
            if (!isExpanded(i)) {
                expandItems(i, true);
            }
        }
    }
}

public void expendSingle()
{
    if (!isExpanded(2)) {
        expandItems(2, true);
    }
}

public static void openArrow(View view) {
    view.animate().setDuration(ARROW_ROTATION_DURATION).rotation(90);
}

public static void closeArrow(View view) {
    view.animate().setDuration(ARROW_ROTATION_DURATION).rotation(0);
}

public int getMode() {
    return mode;
}

public void setMode(int mode) {
    this.mode = mode;
}}

2. PeopleAdapter.java

public class PeopleAdapter extends ExpandableRecyclerAdapter<PeopleAdapter.PeopleListItem> {
public static final int TYPE_PERSON = 1001;

public PeopleAdapter(Context context) {
    super(context);

    setItems(getSampleItems());
}

public static class PeopleListItem extends ExpandableRecyclerAdapter.ListItem {
    public String Text;

    public PeopleListItem(String group) {
        super(TYPE_HEADER);

        Text = group;
    }

    public PeopleListItem(String first, String last) {
        super(TYPE_PERSON);

        Text = first + " " + last;
    }
}

public class HeaderViewHolder extends ExpandableRecyclerAdapter.HeaderViewHolder {
    TextView name;

    public HeaderViewHolder(View view) {
        super(view, (ImageView) view.findViewById(R.id.item_arrow));

        name = (TextView) view.findViewById(R.id.item_header_name);
    }

    public void bind(int position) {
        super.bind(position);

        name.setText(visibleItems.get(position).Text);
    }
}

public class PersonViewHolder extends ExpandableRecyclerAdapter.ViewHolder {
    TextView name;

    public PersonViewHolder(View view) {
        super(view);

        name = (TextView) view.findViewById(R.id.item_name);
    }

    public void bind(int position) {
        name.setText(visibleItems.get(position).Text);
    }
}

@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    switch (viewType) {
        case TYPE_HEADER:
            return new HeaderViewHolder(inflate(R.layout.item_header, parent));
        case TYPE_PERSON:
        default:
            return new PersonViewHolder(inflate(R.layout.item_person, parent));
    }
}

@Override
public void onBindViewHolder(ExpandableRecyclerAdapter.ViewHolder holder, int position) {
    switch (getItemViewType(position)) {
        case TYPE_HEADER:
            ((HeaderViewHolder) holder).bind(position);
            break;
        case TYPE_PERSON:
        default:
            ((PersonViewHolder) holder).bind(position);
            break;
    }
}

private List<PeopleListItem> getSampleItems() {
    List<PeopleListItem> items = new ArrayList<>();

    items.add(new PeopleListItem("Friends"));
    items.add(new PeopleListItem("Bill", "Smith"));
    items.add(new PeopleListItem("John", "Doe"));
    items.add(new PeopleListItem("Frank", "Hall"));
    items.add(new PeopleListItem("Sue", "West"));
    items.add(new PeopleListItem("Family"));
    items.add(new PeopleListItem("Drew", "Smith"));
    items.add(new PeopleListItem("Chris", "Doe"));
    items.add(new PeopleListItem("Alex", "Hall"));
    items.add(new PeopleListItem("Associates"));
    items.add(new PeopleListItem("John", "Jones"));
    items.add(new PeopleListItem("Ed", "Smith"));
    items.add(new PeopleListItem("Jane", "Hall"));
    items.add(new PeopleListItem("Tim", "Lake"));
    items.add(new PeopleListItem("Colleagues"));
    items.add(new PeopleListItem("Carol", "Jones"));
    items.add(new PeopleListItem("Alex", "Smith"));
    items.add(new PeopleListItem("Kristin", "Hall"));
    items.add(new PeopleListItem("Pete", "Lake"));
    items.add(new PeopleListItem("Friends"));
    items.add(new PeopleListItem("Bill", "Smith"));
    items.add(new PeopleListItem("John", "Doe"));
    items.add(new PeopleListItem("Frank", "Hall"));
    items.add(new PeopleListItem("Sue", "West"));
    items.add(new PeopleListItem("Family"));
    items.add(new PeopleListItem("Drew", "Smith"));
    items.add(new PeopleListItem("Chris", "Doe"));
    items.add(new PeopleListItem("Alex", "Hall"));
    items.add(new PeopleListItem("Associates"));
    items.add(new PeopleListItem("John", "Jones"));
    items.add(new PeopleListItem("Ed", "Smith"));
    items.add(new PeopleListItem("Jane", "Hall"));
    items.add(new PeopleListItem("Tim", "Lake"));
    items.add(new PeopleListItem("Colleagues"));
    items.add(new PeopleListItem("Carol", "Jones"));
    items.add(new PeopleListItem("Alex", "Smith"));
    items.add(new PeopleListItem("Kristin", "Hall"));
    items.add(new PeopleListItem("Pete", "Lake"));
    items.add(new PeopleListItem("Friends"));
    items.add(new PeopleListItem("Bill", "Smith"));
    items.add(new PeopleListItem("John", "Doe"));
    items.add(new PeopleListItem("Frank", "Hall"));
    items.add(new PeopleListItem("Sue", "West"));
    items.add(new PeopleListItem("Family"));
    items.add(new PeopleListItem("Drew", "Smith"));
    items.add(new PeopleListItem("Chris", "Doe"));
    items.add(new PeopleListItem("Alex", "Hall"));
    items.add(new PeopleListItem("Associates"));
    items.add(new PeopleListItem("John", "Jones"));
    items.add(new PeopleListItem("Ed", "Smith"));
    items.add(new PeopleListItem("Jane", "Hall"));
    items.add(new PeopleListItem("Tim", "Lake"));
    items.add(new PeopleListItem("Colleagues"));
    items.add(new PeopleListItem("Carol", "Jones"));
    items.add(new PeopleListItem("Alex", "Smith"));
    items.add(new PeopleListItem("Kristin", "Hall"));
    items.add(new PeopleListItem("Pete", "Lake"));
    return items;
}

}

Но я не могу переопределить метод "onCreateViewHolder" с возвращаемым типом ViewHolder & "onBindViewHolder" с типом аргумента ExpandableRecyclerAdapter.ViewHolder для класса PeopleAdapter в случае xamarin.

Заранее спасибо.

Вот мой код C #.

1. ExpandableRecyclerAdapter.cs

public abstract class ExpandableRecyclerAdapter : RecyclerView.Adapter
{
    protected internal Context mContext;
    protected internal IList<ListItem> allItems = new List<ListItem>();
    protected internal IList<ListItem> visibleItems = new List<ListItem>();
    private IList<int> indexList = new List<int>();
    private SparseIntArray expandMap = new SparseIntArray();
    private int mode;

    protected internal const int TYPE_HEADER = 1000;

    private const int ARROW_ROTATION_DURATION = 150;

    public const int MODE_NORMAL = 0;
    public const int MODE_ACCORDION = 1;

    public ExpandableRecyclerAdapter(Context context)
    {
        mContext = context;
    }

    public class ListItem
    {
        public int ItemType;

        public ListItem(int itemType)
        {
            ItemType = itemType;
        }
    }

    public override long GetItemId(int i)
    {
        return i;
    }

    public override int ItemCount
    {
        get
        {
            return visibleItems == null ? 0 : visibleItems.Count;
        }
    }

    protected internal virtual View inflate(int resourceID, ViewGroup viewGroup)
    {
        return LayoutInflater.From(mContext).Inflate(resourceID, viewGroup, false);
    }

    public class ViewHolder : RecyclerView.ViewHolder
    {
        public ViewHolder(View view) : base(view)
        {

        }
    }

    public class HeaderViewHolder : ViewHolder,View.IOnClickListener
    {
        internal ImageView arrow;
        public HeaderViewHolder(View view, ImageView arrow) : base(view)
        {
            this.arrow = arrow;
            view.SetOnClickListener(this);
        }

        protected internal virtual void handleClick()
        {
            if (toggleExpandedItems(LayoutPosition, false))
            {
                openArrow(arrow);
            }
            else
            {
                closeArrow(arrow);
            }
        }

        public virtual void bind(int position)
        {
            arrow.Rotation = isExpanded(position) ? 90 : 0;
        }
        public void OnClick(View v)
        {
            handleClick();
        }
    }

    public virtual bool toggleExpandedItems(int position, bool notify)
    {
        if (isExpanded(position))
        {
            collapseItems(position, notify);
            return false;
        }
        else
        {
            expandItems(position, notify);

            if (mode == MODE_ACCORDION)
            {
                collapseAllExcept(position);
            }

            return true;
        }
    }

    public virtual void expandItems(int position, bool notify)
    {
        int count = 0;
        int index = indexList[position];
        int insert = position;

        for (int i = index + 1; i < allItems.Count && allItems[i].ItemType != TYPE_HEADER; i++)
        {
            insert++;
            count++;
            visibleItems.Insert(insert, allItems[i]);
            indexList.Insert(insert, i);
        }

        NotifyItemRangeInserted(position + 1, count);

        int allItemsPosition = indexList[position];
        expandMap.Put(allItemsPosition, 1);

        if (notify)
        {
            NotifyItemChanged(position);
        }
    }

    public virtual void collapseItems(int position, bool notify)
    {
        int count = 0;
        int index = indexList[position];

        for (int i = index + 1; i < allItems.Count && allItems[i].ItemType != TYPE_HEADER; i++)
        {
            count++;
            visibleItems.RemoveAt(position + 1);
            indexList.RemoveAt(position + 1);
        }

        NotifyItemRangeRemoved(position + 1, count);

        int allItemsPosition = indexList[position];
        expandMap.Delete(allItemsPosition);

        if (notify)
        {
            NotifyItemChanged(position);
        }
    }
    public class StaticViewHolder : ViewHolder
    {
        public StaticViewHolder(View view):base(view)
        {
        }
    }

    public class ItemViewHolder : ViewHolder
    {
        public ItemViewHolder(View view) : base(view)
        {
        }
    }   
    protected bool isExpanded(int position)
    {
        int allItemsPosition = indexList[position];
        return expandMap.Get(allItemsPosition, -1) >= 0;
    }

    public override int GetItemViewType(int position)
    {
        return  visibleItems[position].ItemType;
    }

    public void setItems(List<ListItem> items)
    {
        allItems = items;
        List<ListItem> visibleItems = new List<ListItem>();
        expandMap.Clear();
        indexList.Clear();

        for (int i = 0; i < items.Count; i++)
        {
            if (items[i].ItemType == TYPE_HEADER)
            {
                indexList.Add(i);
                visibleItems.Add(items[i]);
            }
        }

        this.visibleItems = visibleItems;
        NotifyDataSetChanged();
    }

    protected void notifyItemInserted(int allItemsPosition, int visiblePosition)
    {
        incrementIndexList(allItemsPosition, visiblePosition, 1);
        incrementExpandMapAfter(allItemsPosition, 1);

        if (visiblePosition >= 0)
        {
            NotifyItemInserted(visiblePosition);
        }
    }


    protected void removeItemAt(int visiblePosition)
    {
        int allItemsPosition = indexList[visiblePosition];

        //allItems.Remove(allItemsPosition);
        //visibleItems.Remove(visiblePosition);

        incrementIndexList(allItemsPosition, visiblePosition, -1);
        incrementExpandMapAfter(allItemsPosition, -1);

        NotifyItemRemoved(visiblePosition);
    }

    private void incrementExpandMapAfter(int position, int direction)
    {
        SparseIntArray newExpandMap = new SparseIntArray();

        for (int i = 0; i < expandMap.Size(); i++)
        {
            int index = expandMap.KeyAt(i);
            newExpandMap.Put(index < position ? index : index + direction, 1);
        }

        expandMap = newExpandMap;
    }

    private void incrementIndexList(int allItemsPosition, int visiblePosition, int direction)
    {
        List<int> newIndexList = new List<int>();

        for (int i = 0; i < indexList.Count; i++)
        {
            if (i == visiblePosition)
            {
                if (direction > 0)
                {
                    newIndexList.Add(allItemsPosition);
                }
            }

            int val = indexList[i];
            newIndexList.Add(val < allItemsPosition ? val : val + direction);
        }

        indexList = newIndexList;
    }

    public void collapseAll()
    {
        collapseAllExcept(-1);
    }

    public void collapseAllExcept(int position)
    {
        for (int i = visibleItems.Count - 1; i >= 0; i--)
        {
            if (i != position && GetItemViewType(i) == TYPE_HEADER)
            {
                if (isExpanded(i))
                {
                    collapseItems(i, true);
                }
            }
        }
    }

    public void expandAll()
    {
        for (int i = visibleItems.Count - 1; i >= 0; i--)
        {
            if (GetItemViewType(i) == TYPE_HEADER)
            {
                if (!isExpanded(i))
                {
                    expandItems(i, true);
                }
            }
        }
    }

    public void expendSingle()
    {
        if (!isExpanded(2))
        {
            expandItems(2, true);
        }
    }

    public static void openArrow(View view)
    {
        view.Animate().SetDuration(ARROW_ROTATION_DURATION).Rotation(90);
    }

    public static void closeArrow(View view)
    {
        view.Animate().SetDuration(ARROW_ROTATION_DURATION).Rotation(0);
    }

    public int getMode()
    {
        return mode;
    }

    public void setMode(int mode)
    {
        this.mode = mode;
    }
}

2. PeopleAdapter.cs

public class PeopleAdapter : ExpandableRecyclerAdapter
{
    public const int TYPE_PERSON = 1001;

    public PeopleAdapter(Context context):base(context)
    {         
        setItems(getSampleItems());
    }

    public class PeopleListItem : ExpandableRecyclerAdapter.ListItem
    {
        public string Text;

        public PeopleListItem(String group):base(TYPE_HEADER)
        {
            Text = group;
        }

        public PeopleListItem(String first, String last) : base(TYPE_PERSON)
        {
            Text = first + " " + last;
        }
    }

    public class HeaderViewHolder : ExpandableRecyclerAdapter.HeaderViewHolder
    {
        TextView name;

        public HeaderViewHolder(View view): base(view, (ImageView)view.FindViewById(Resource.Id.item_arrow))
        {
            name = (TextView)view.FindViewById(Resource.Id.item_header_name);
        }

        public void bind(int position)
        {
            base.bind(position);
            name.SetText(visibleItems[position].Text);
        }
    }

    public class PersonViewHolder : ExpandableRecyclerAdapter.ViewHolder
    {
        TextView name;

        public PersonViewHolder(View view):base(view)
        {
            name = (TextView)view.FindViewById(Resource.Id.item_name);
        }
        public void bind(int position)
        {
            name.SetText(visibleItems[position].Text);
        }
    }


    public override void OnBindViewHolder(ExpandableRecyclerAdapter.ViewHolder holder, int position)
    {
        switch (GetItemViewType(position))
        {
            case TYPE_HEADER:
                ((HeaderViewHolder)holder).bind(position);
                break;
            case TYPE_PERSON:
            default:
                ((PersonViewHolder)holder).bind(position);
                break;
        }
    }

    public override ViewHolder OnCreateViewHolder(ViewGroup parent, int viewType)
    {
        switch (viewType)
        {
            case TYPE_HEADER:
                return new HeaderViewHolder(inflate(Resource.Layout.item_header, parent));
            case TYPE_PERSON:
            default:
                return new PersonViewHolder(inflate(Resource.Layout.item_person, parent));
        }
    }

    private List<PeopleListItem> getSampleItems()
    {
        List<PeopleListItem> items = new List<PeopleListItem>();

        items.Add(new PeopleListItem("Friends"));
        items.Add(new PeopleListItem("Bill", "Smith"));
        items.Add(new PeopleListItem("John", "Doe"));
        items.Add(new PeopleListItem("Frank", "Hall"));
        items.Add(new PeopleListItem("Sue", "West"));
        items.Add(new PeopleListItem("Family"));
        items.Add(new PeopleListItem("Drew", "Smith"));
        items.Add(new PeopleListItem("Chris", "Doe"));
        items.Add(new PeopleListItem("Alex", "Hall"));
        items.Add(new PeopleListItem("Associates"));
        items.Add(new PeopleListItem("John", "Jones"));
        items.Add(new PeopleListItem("Ed", "Smith"));
        items.Add(new PeopleListItem("Jane", "Hall"));
        items.Add(new PeopleListItem("Tim", "Lake"));
        items.Add(new PeopleListItem("Colleagues"));
        items.Add(new PeopleListItem("Carol", "Jones"));
        items.Add(new PeopleListItem("Alex", "Smith"));
        items.Add(new PeopleListItem("Kristin", "Hall"));
        items.Add(new PeopleListItem("Pete", "Lake"));
        items.Add(new PeopleListItem("Friends"));
        items.Add(new PeopleListItem("Bill", "Smith"));
        items.Add(new PeopleListItem("John", "Doe"));
        items.Add(new PeopleListItem("Frank", "Hall"));
        items.Add(new PeopleListItem("Sue", "West"));
        items.Add(new PeopleListItem("Family"));
        items.Add(new PeopleListItem("Drew", "Smith"));
        items.Add(new PeopleListItem("Chris", "Doe"));
        items.Add(new PeopleListItem("Alex", "Hall"));
        items.Add(new PeopleListItem("Associates"));
        items.Add(new PeopleListItem("John", "Jones"));
        items.Add(new PeopleListItem("Ed", "Smith"));
        items.Add(new PeopleListItem("Jane", "Hall"));
        items.Add(new PeopleListItem("Tim", "Lake"));
        items.Add(new PeopleListItem("Colleagues"));
        items.Add(new PeopleListItem("Carol", "Jones"));
        items.Add(new PeopleListItem("Alex", "Smith"));
        items.Add(new PeopleListItem("Kristin", "Hall"));
        items.Add(new PeopleListItem("Pete", "Lake"));
        items.Add(new PeopleListItem("Friends"));
        items.Add(new PeopleListItem("Bill", "Smith"));
        items.Add(new PeopleListItem("John", "Doe"));
        items.Add(new PeopleListItem("Frank", "Hall"));
        items.Add(new PeopleListItem("Sue", "West"));
        items.Add(new PeopleListItem("Family"));
        items.Add(new PeopleListItem("Drew", "Smith"));
        items.Add(new PeopleListItem("Chris", "Doe"));
        items.Add(new PeopleListItem("Alex", "Hall"));
        items.Add(new PeopleListItem("Associates"));
        items.Add(new PeopleListItem("John", "Jones"));
        items.Add(new PeopleListItem("Ed", "Smith"));
        items.Add(new PeopleListItem("Jane", "Hall"));
        items.Add(new PeopleListItem("Tim", "Lake"));
        items.Add(new PeopleListItem("Colleagues"));
        items.Add(new PeopleListItem("Carol", "Jones"));
        items.Add(new PeopleListItem("Alex", "Smith"));
        items.Add(new PeopleListItem("Kristin", "Hall"));
        items.Add(new PeopleListItem("Pete", "Lake"));
        return items;
    }}