在C#中，接口可以实例化吗？

我正在阅读中的代码here。我发现private ITreeModel _model;在 TreeList.cs 中：

namespace Aga.Controls.Tree
{
    public class TreeList: ListView
    {
        #region Properties
        //...
        private ITreeModel _model;
        public ITreeModel Model
        {
            //...
        }
        //...
    }
}

ITreeModel 是 ITreeModel.cs 中的一个接口：

namespace Aga.Controls.Tree
{
    public interface ITreeModel
    {
        /// <summary>
        /// Get list of children of the specified parent
        /// </summary>
        IEnumerable GetChildren(object parent);

        /// <summary>
        /// returns wheather specified parent has any children or not.
        /// </summary>
        bool HasChildren(object parent);
    }
}

the _model是实例化对象吗？

Edited:

TreeList.cs:

namespace Aga.Controls.Tree
{
    public class TreeList: ListView
    {
        #region Properties

        /// <summary>
        /// Internal collection of rows representing visible nodes, actually displayed in the ListView
        /// </summary>
        internal ObservableCollectionAdv<TreeNode> Rows
        {
            get;
            private set;
        } 

        private ITreeModel _model;
        public ITreeModel Model
        {
            get { return _model; }
            set 
            {
                if (_model != value)
                {
                    _model = value;
                    _root.Children.Clear();
                    Rows.Clear();
                    CreateChildrenNodes(_root);
                }
            }
        }

        private TreeNode _root;
        internal TreeNode Root
        {
            get { return _root; }
        }
        //....
    }
}

}

Edited2:

某处：

public partial class RegistrySample : UserControl
{
    public RegistrySample()
    {
        InitializeComponent();
        _tree.Model = new RegistryModel();
    }
}

class RegistryModel : ITreeModel

当然你可以这样做，但是底层对象必须实现这个接口。所以你可以做类似的事情

ITreeModel _model  = new TreeModel();

Where

public class TreeModel:ITreeModel
{
  ...
}