Item-Level Presentation Models for WPF

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;

using HappyNomad.Examples.PresentationModel.GUI.Model;

namespace HappyNomad.Examples.PresentationModel.GUI {

	/// <summary>
	/// Interaction logic for Demo2.xaml
	/// </summary>
	public partial class Demo2 : UserControl {
		private SampleTreeNodeView rootWrapper;
		
		public Demo2() {
			InitializeComponent();

			//Build sample presentation-model objects:
			rootWrapper = new SampleTreeNodeView();
			sampleTreeView.ItemsSource = rootWrapper.SubItems; //SampleTreeNode.Root.SubNodes;
		}

		private void addButton_Click( object sender, RoutedEventArgs args ) {
			SampleTreeNodeView selected = (SampleTreeNodeView)sampleTreeView.SelectedItem; //get selected item
			SampleTreeNode newItem = new SampleTreeNode( editItemBox.Text ); //create new item
			int newIndex = selected.Parent.SubItems.IndexOf( selected ) + 1; //determine new item's position

			//Insert new item into domain-model tree structure:
			selected.Parent.DomainItem.SubNodes.Insert( newIndex, newItem );

			//Select new item in UI:
			rootWrapper.FindDescendant( newItem ).IsSelected = true;
			sampleTreeView.Focus();
		}

		private void updateButton_Click( object sender, RoutedEventArgs args ) {
			BindingExpression be = editItemBox.GetBindingExpression( TextBox.TextProperty );
			be.UpdateSource(); //update sampleTreeView.SelectedItem.DomainItem.Name with editItemBox.Text's value
			sampleTreeView.Focus();
		}

		private void demoteButton_Click( object sender, RoutedEventArgs args ) {
			SampleTreeNodeView viewToMove = (SampleTreeNodeView)sampleTreeView.SelectedItem; //get selected item
			SampleTreeNode itemToMove = viewToMove.DomainItem; //get selected domain object

			SampleTreeNode oldParent = itemToMove.ParentNode; //Determine former parent...
			int oldIndex = oldParent.SubNodes.IndexOf( itemToMove ); //and index.
			if ( oldIndex == 0 ) return; //nowhere to demote to, so finished

			SampleTreeNode newParent = oldParent.SubNodes[oldIndex - 1]; //Determine new parent...
			int newIndex = newParent.SubNodes.Count; //and index.

			itemToMove.ParentNode = null; //move the selected item
			newParent.SubNodes.Insert( newIndex, itemToMove );

			viewToMove.Parent.IsExpanded = true; //Make sure the moved item is visible
			viewToMove.IsSelected = true; //and that it's selected.
			sampleTreeView.Focus(); //avoid some strange WPF behaviour
		}

		private void deleteButton_Click( object sender, RoutedEventArgs args ) {
			SampleTreeNodeView selected = (SampleTreeNodeView)sampleTreeView.SelectedItem; //get selected item
			selected.DomainItem.ParentNode = null; //remove subtree
			sampleTreeView.Focus();
		}
	}
}