TreeView - NSOutlineViewDataSource

TreeViewDataSource.cs

    public class TreeViewDataSource : NSOutlineViewDataSource
    {
        private readonly List<TreeItem> source = new List<TreeItem>();

        public TreeViewDataSource()
        {}

        public void Add(TreeItem item)
        {
            source.Add(item);
        }

        public void Add(IEnumerable<TreeItem> items)
        {
            source.AddRange(items);
        }

        public override int GetChildrenCount(NSOutlineView outlineView, NSObject item)
        {
            if (item == null) return source.Count;
            return (item as TreeItem).Children.Count;
        }

        public override bool ItemExpandable(NSOutlineView outlineView, NSObject item)
        {
            if(item == null) return false;
            return (item as TreeItem).Children.Count > 0;
        }

        public override NSObject GetChild(NSOutlineView outlineView, int childIndex, NSObject item)
        {
            if (item == null)
            {
                return source[childIndex];
            }
            return (item as TreeItem).Children[childIndex];
        }

        public override NSObject GetObjectValue(NSOutlineView outlineView, NSTableColumn tableColumn, NSObject item)
        {
            if (item != null)
            {
                return (NSString)item.ToString();
            }
            return (NSString)"Test";
        }
    }

    public class TreeItem : NSObject, IEnumerable<TreeItem>, IEnumerable
    {
        public TreeItem(string caption)
        {
            Caption = caption;
            Children = new List<TreeItem>();
        }

        public string Caption { get; set; }
        public List<TreeItem> Children { get; set; }

        public void Add(TreeItem child)
        {
            Children.Add(child);
        }

        public override string ToString()
        {
            return Caption;
        }

        #region IEnumerable

        IEnumerator<TreeItem> IEnumerable<TreeItem>.GetEnumerator()
        {
            return Children.GetEnumerator();
        }

        IEnumerator IEnumerable.GetEnumerator()
        {
            return Children.GetEnumerator();
        }

        #endregion
    }