From a3740275f1c5336831995b27dc8a7bb032e3aa98 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Jean-Philippe=20Bruy=C3=A8re?= <jp_bruyere@hotmail.com>
Date: Sat, 17 Feb 2018 12:13:48 +0100
Subject: [PATCH] first working test with hierarchical TemplatedGroup with only
 one root Level

---
 CrowIDE/ui/EditPaneItems.template        |  12 +-
 CrowIDE/ui/ProjectTree.template          |  27 ++---
 Templates/DirectoryView.template         |   3 +-
 src/CompilerServices/CompilerServices.cs |   3 +
 src/GraphicObjects/TemplatedGroup.cs     | 144 ++++++++++++-----------
 src/Instantiator.cs                      |  14 ++-
 src/ItemTemplate.cs                      |  71 +++++++----
 7 files changed, 155 insertions(+), 119 deletions(-)

diff --git a/CrowIDE/ui/EditPaneItems.template b/CrowIDE/ui/EditPaneItems.template
index 5879e2a7..ebe6120f 100644
--- a/CrowIDE/ui/EditPaneItems.template
+++ b/CrowIDE/ui/EditPaneItems.template
@@ -1,8 +1,10 @@
 <?xml version="1.0" encoding="UTF-8" ?>
-<ItemTemplate>
-	<TabItem Caption="{DisplayName}" QueryClose="OnQueryClose"/>
+<ItemTemplate>	
+	<TabItem Caption="{DisplayName}" QueryClose="OnQueryClose">
+		<Label Text="Error" Background="Red"/>
+	</TabItem>
 </ItemTemplate>
-<ItemTemplate DataType=".cs">
+<ItemTemplate DataType=".cs" DataTest="Extension">
 	<TabItem Caption="{DisplayName}" QueryClose="OnQueryClose">
 		<VerticalStack>
 			<HorizontalStack Height="Stretched" >
@@ -31,12 +33,12 @@
 		</VerticalStack>
 	</TabItem>
 </ItemTemplate>
-<ItemTemplate DataType=".svg">
+<ItemTemplate DataType=".svg" DataTest="Extension">
 	<TabItem Caption="{DisplayName}" QueryClose="OnQueryClose">
 		<Image Path="{AbsolutePath}"/>
 	</TabItem>
 </ItemTemplate>
-<ItemTemplate DataType=".crow">		
+<ItemTemplate DataType=".crow" DataTest="Extension">		
 	<TabItem Caption="{DisplayName}" QueryClose="OnQueryClose">
 		<VerticalStack>
 			<Label Width="Stretched" Margin="1" Text="{HoverWidget}"/>
diff --git a/CrowIDE/ui/ProjectTree.template b/CrowIDE/ui/ProjectTree.template
index 2ec8419a..eadb733c 100644
--- a/CrowIDE/ui/ProjectTree.template
+++ b/CrowIDE/ui/ProjectTree.template
@@ -2,7 +2,7 @@
 <ItemTemplate>
 	<Label Text="{}" Background="DarkRed" Foreground="White"/>
 </ItemTemplate>
-<ItemTemplate DataType="CrowIDE.Project" Data="RootItems">
+<ItemTemplate DataType="CrowIDE.Project" Data="RootItems" DataTest="Type">
 	<Expandable Caption="{Name}" ContextCommands="{Commands}" >
 		<Template>
 			<VerticalStack>
@@ -28,30 +28,27 @@
 		</Template>
 		<HorizontalStack Height="Fit">
 			<GraphicObject Width="8" Height="10"/>
-			<TreeView Name="List" Height="Fit" DataTest="Type"
-				Template="#Crow.Templates.treeList.template" />
+			<VerticalStack Height="Fit" Name="ItemsContainer"/>
 		</HorizontalStack>
 	</Expandable>
 </ItemTemplate>
-<ItemTemplate DataType="ReferenceGroup" Data="ChildNodes">
+<ItemTemplate DataType="ReferenceGroup" Data="ChildNodes" DataTest="Type">
 	<Expandable Caption="{DisplayName}" Template="#Crow.TreeExpandable.template" >
 		<HorizontalStack Height="Fit">
 			<GraphicObject Width="8" Height="10"/>
-			<TreeView Name="List" Height="Fit" DataTest="Type"
-				Template="#Crow.Templates.treeList.template" />
+			<VerticalStack Height="Fit" Name="ItemsContainer"/>
 		</HorizontalStack>
 	</Expandable>
 </ItemTemplate>
-<ItemTemplate DataType="VirtualGroup" Data="ChildNodes">
+<ItemTemplate DataType="VirtualGroup" Data="ChildNodes" DataTest="Type">
 	<Expandable Caption="{DisplayName}" Template="#Crow.TreeExpandable.template" >
 		<HorizontalStack Height="Fit">
 			<GraphicObject Width="8" Height="10"/>
-			<TreeView Name="List" Height="Fit" DataTest="Type"
-				Template="#Crow.Templates.treeList.template" />
+			<VerticalStack Height="Fit" Name="ItemsContainer"/>
 		</HorizontalStack>
 	</Expandable>
 </ItemTemplate>
-<ItemTemplate DataType="Folder">
+<ItemTemplate DataType="Folder" DataTest="Type">
 	<Border CornerRadius="2" Margin="0" Focusable="true"  Height="Fit" Width="Stretched" Foreground="Transparent"
 			MouseEnter="{Foreground=DimGray}"
 			MouseLeave="{Foreground=Transparent}">
@@ -62,7 +59,7 @@
 		</HorizontalStack>
 	</Border>
 </ItemTemplate>
-<ItemTemplate DataType="Reference">
+<ItemTemplate DataType="Reference" DataTest="Type">
 	<Border CornerRadius="2" Margin="0" Focusable="true"  Height="Fit" Width="Stretched" Foreground="Transparent"
 			MouseEnter="{Foreground=DimGray}"
 			MouseLeave="{Foreground=Transparent}">
@@ -73,7 +70,7 @@
 		</HorizontalStack>
 	</Border>
 </ItemTemplate>
-<ItemTemplate DataType="ProjectReference">
+<ItemTemplate DataType="ProjectReference" DataTest="Type">
 	<Border CornerRadius="2" Margin="0" Focusable="true"  Height="Fit" Width="Stretched" Foreground="Transparent"
 			MouseEnter="{Foreground=DimGray}"
 			MouseLeave="{Foreground=Transparent}">
@@ -84,7 +81,7 @@
 		</HorizontalStack>
 	</Border>
 </ItemTemplate>
-<ItemTemplate DataType="Compile">	
+<ItemTemplate DataType="Compile" DataTest="Type">	
 	<Border CornerRadius="2" Margin="0" Focusable="true"  Height="Fit" Width="Stretched" Foreground="Transparent"
 			MouseEnter="{Foreground=DimGray}"
 			MouseLeave="{Foreground=Transparent}">
@@ -95,7 +92,7 @@
 		</HorizontalStack>
 	</Border>
 </ItemTemplate>
-<ItemTemplate DataType="EmbeddedResource">
+<ItemTemplate DataType="EmbeddedResource" DataTest="Type">
 	<Border CornerRadius="2" Margin="0" Focusable="true"  Height="Fit" Width="Stretched" Foreground="Transparent"
 			MouseEnter="{Foreground=DimGray}"
 			MouseLeave="{Foreground=Transparent}">
@@ -106,7 +103,7 @@
 		</HorizontalStack>
 	</Border>
 </ItemTemplate>
-<ItemTemplate DataType="None">
+<ItemTemplate DataType="None" DataTest="Type">
 	<Border CornerRadius="2" Margin="0" Focusable="true"  Height="Fit" Width="Stretched" Foreground="Transparent"
 			MouseEnter="{Foreground=DimGray}"
 			MouseLeave="{Foreground=Transparent}">
diff --git a/Templates/DirectoryView.template b/Templates/DirectoryView.template
index 42e9020f..826dd3f8 100755
--- a/Templates/DirectoryView.template
+++ b/Templates/DirectoryView.template
@@ -37,8 +37,7 @@
 			</Template>
 			<HorizontalStack Height="Fit">
 				<GraphicObject Width="12" Height="10"/>
-				<TreeView Name="List" Height="Fit"
-					Template="#Crow.Templates.treeList.template" />
+				<VerticalStack Height="Fit" Name="ItemsContainer"/>
 			</HorizontalStack>
 		</Expandable>
 	</ItemTemplate>
diff --git a/src/CompilerServices/CompilerServices.cs b/src/CompilerServices/CompilerServices.cs
index 16d28490..dbd12d41 100644
--- a/src/CompilerServices/CompilerServices.cs
+++ b/src/CompilerServices/CompilerServices.cs
@@ -92,6 +92,9 @@ namespace Crow.IML
 		internal static MethodInfo miAddITemp = typeof(Dictionary<string, ItemTemplate>).GetMethod ("set_Item", new Type[] { typeof(string), typeof(ItemTemplate) });
 		internal static MethodInfo miGetITempFromDic = typeof(Dictionary<string, ItemTemplate>).GetMethod ("get_Item", new Type[] { typeof(string) });
 		internal static FieldInfo fldItemTemplates = typeof(TemplatedGroup).GetField("ItemTemplates");
+		internal static MethodInfo miLoadPage = typeof(TemplatedGroup).GetMethod ("loadPage", BindingFlags.Instance | BindingFlags.NonPublic| BindingFlags.Public);
+		internal static MethodInfo miIsAlreadyExpanded = typeof(TemplatedGroup).GetMethod("emitHelperIsAlreadyExpanded", BindingFlags.Instance | BindingFlags.NonPublic);
+		
 		internal static MethodInfo miCreateExpDel = typeof(ItemTemplate).GetMethod ("CreateExpandDelegate");
 		internal static FieldInfo fiFetchMethodName = typeof(ItemTemplate).GetField("fetchMethodName", BindingFlags.Instance | BindingFlags.NonPublic);
 		#region tree handling methods
diff --git a/src/GraphicObjects/TemplatedGroup.cs b/src/GraphicObjects/TemplatedGroup.cs
index ef099f93..c72bfbcb 100644
--- a/src/GraphicObjects/TemplatedGroup.cs
+++ b/src/GraphicObjects/TemplatedGroup.cs
@@ -34,6 +34,7 @@ using System.Collections;
 using System.Threading;
 using System.Linq;
 using Crow.IML;
+using System.Diagnostics;
 
 namespace Crow
 {
@@ -45,7 +46,7 @@ namespace Crow
 		#endregion
 
 		protected Group items;
-		string _itemTemplate, _dataTest;
+		string _itemTemplate, dataTest;
 
 		#region events
 		public event EventHandler<SelectionChangeEventArgs> SelectedItemChanged;
@@ -66,6 +67,11 @@ namespace Crow
 		//but then i should test if null in msil gen
 		public Dictionary<string, ItemTemplate> ItemTemplates = new Dictionary<string, Crow.ItemTemplate>();
 
+		/// <summary>
+		/// Keep track of expanded subnodes and closed time to unload
+		/// </summary>
+		//Dictionary<GraphicObject, Stopwatch> nodes = new Dictionary<GraphicObject, Stopwatch>();
+		internal List<GraphicObject> nodes = new List<GraphicObject>();
 		/// <summary>
 		/// Item templates file path, on disk or embedded.
 		/// 
@@ -106,14 +112,14 @@ namespace Crow
 		/// <value>The data property test.</value>
 		[XmlAttributeAttribute][DefaultValue("TypeOf")]
 		public string DataTest {
-			get { return _dataTest; }
+			get { return dataTest; }
 			set {
-				if (value == _dataTest)
+				if (value == dataTest)
 					return;
 
-				_dataTest = value;
+				dataTest = value;
 
-				NotifyValueChanged("DataTest", _dataTest);
+				NotifyValueChanged("DataTest", dataTest);
 			}
 		}
 		#endregion
@@ -170,7 +176,7 @@ namespace Crow
 				if (value == data)
 					return;
 
-				cancelLoadingThread ();
+				//cancelLoadingThread ();
 
 				if (data is IObservableList) {
 					IObservableList ol = data as IObservableList;
@@ -188,15 +194,17 @@ namespace Crow
 
 				NotifyValueChanged ("Data", data);
 
-				lock (CurrentInterface.LayoutMutex)
+				//lock (CurrentInterface.LayoutMutex)
 					ClearItems ();
 
 				if (data == null)
 					return;
 
-				loadingThread = new CrowThread (this, loading);
-				loadingThread.Finished += (object sender, EventArgs e) => (sender as TemplatedGroup).Loaded.Raise (sender, e);
-				loadingThread.Start ();
+//				loadingThread = new CrowThread (this, loading);
+//				loadingThread.Finished += (object sender, EventArgs e) => (sender as TemplatedGroup).Loaded.Raise (sender, e);
+//				loadingThread.Start ();
+
+				loadPage (data, items, dataTest);
 
 				NotifyValueChanged ("SelectedIndex", _selectedIndex);
 				NotifyValueChanged ("SelectedItem", SelectedItem);
@@ -223,7 +231,7 @@ namespace Crow
 //				int i = e.Index % itemPerPage;
 //				(items.Children [p] as Group).InsertChild (i, e.Element);
 			} else
-				loadItem (e.Index, items);
+				loadItem (e.Element, items, dataTest);
 		}
 
 		[XmlAttributeAttribute][DefaultValue("SteelBlue")]
@@ -319,69 +327,62 @@ namespace Crow
 		/// <summary>
 		/// Items loading thread
 		/// </summary>
-		void loading(){
-			//if (!ItemTemplates.ContainsKey ("default"))
-			//	ItemTemplates ["default"] = Interface.GetItemTemplate (ItemTemplate);
-
-			for (int i = 1; i <= (data.Count / itemPerPage) + 1; i++) {
-				if ((bool)loadingThread?.cancelRequested) {
-					this.Dispose ();
-					return;
-				}
-				loadPage (i);
-				Thread.Sleep (1);
-			}
-		}
+//		void loading(){
+//			//if (!ItemTemplates.ContainsKey ("default"))
+//			//	ItemTemplates ["default"] = Interface.GetItemTemplate (ItemTemplate);
+//
+//			for (int i = 1; i <= (data.Count / itemPerPage) + 1; i++) {
+//				if ((bool)loadingThread?.cancelRequested) {
+//					this.Dispose ();
+//					return;
+//				}
+//				loadPage (i);
+//				Thread.Sleep (1);
+//			}
+//		}
 		void cancelLoadingThread(){
 			if (loadingThread != null)
 				loadingThread.Cancel ();
 		}
-		void loadPage(int pageNum)
+		void loadPage(IList _data, Group page, string _dataTest)
 		{
 			#if DEBUG_LOAD
 			Stopwatch loadingTime = new Stopwatch ();
 			loadingTime.Start ();
 			#endif
 
-			Group page;
-			if (typeof(TabView).IsAssignableFrom (items.GetType ())||
-				typeof(Menu).IsAssignableFrom (this.GetType())||
-				typeof(Wrapper).IsAssignableFrom (items.GetType ())) {
-				page = items;
-				itemPerPage = int.MaxValue;
-			} else if (typeof(GenericStack).IsAssignableFrom (items.GetType ())) {
-				GenericStack gs = new GenericStack (items.CurrentInterface);
-				gs.Orientation = (items as GenericStack).Orientation;
-				gs.Width = items.Width;
-				gs.Height = items.Height;
-				gs.VerticalAlignment = items.VerticalAlignment;
-				gs.HorizontalAlignment = items.HorizontalAlignment;
-				page = gs;
-				page.Name = "page" + pageNum;
-				isPaged = true;
-			} else {
-				page = Activator.CreateInstance (items.GetType ()) as Group;
-				page.CurrentInterface = items.CurrentInterface;
-				page.Initialize ();
-				page.Name = "page" + pageNum;
-				isPaged = true;
-			}
-
-			for (int i = (pageNum - 1) * itemPerPage; i < pageNum * itemPerPage; i++) {
-				if (i >= data.Count)
-					break;
-				if ((bool)loadingThread?.cancelRequested) {
-					page.Dispose ();
-					return;
-				}
 
-				loadItem (i, page);
+//			if (typeof(TabView).IsAssignableFrom (items.GetType ())||
+//				typeof(Menu).IsAssignableFrom (this.GetType())||
+//				typeof(Wrapper).IsAssignableFrom (items.GetType ())) {
+				//page = items;
+				itemPerPage = int.MaxValue;
+//			} else if (typeof(GenericStack).IsAssignableFrom (items.GetType ())) {
+//				GenericStack gs = new GenericStack (items.CurrentInterface);
+//				gs.Orientation = (items as GenericStack).Orientation;
+//				gs.Width = items.Width;
+//				gs.Height = items.Height;
+//				gs.VerticalAlignment = items.VerticalAlignment;
+//				gs.HorizontalAlignment = items.HorizontalAlignment;
+//				page = gs;
+//				page.Name = "page" + pageNum;
+//				isPaged = true;
+//			} else {
+//				page = Activator.CreateInstance (items.GetType ()) as Group;
+//				page.CurrentInterface = items.CurrentInterface;
+//				page.Initialize ();
+//				page.Name = "page" + pageNum;
+//				isPaged = true;
+//			}
+
+			for (int i = 0; i < _data.Count; i++) {
+				loadItem (_data[i], page, _dataTest);
 			}
 
-			if (page == items)
-				return;
-			lock (CurrentInterface.LayoutMutex)
-				items.AddChild (page);
+//			if (page == items)
+//				return;
+//			lock (CurrentInterface.LayoutMutex)
+//				items.AddChild (page);
 
 			#if DEBUG_LOAD
 			loadingTime.Stop ();
@@ -390,23 +391,23 @@ namespace Crow
 			loadingTime.ElapsedMilliseconds, this.ToString());
 			#endif
 		}
-		string getItempKey(Type dataType, object o){
+		string getItempKey(Type dataType, object o, string propertyName){
 			try {
-				return dataType.GetProperty (_dataTest).GetGetMethod ().Invoke (o, null)?.ToString();
+				return dataType.GetProperty (propertyName).GetGetMethod ().Invoke (o, null)?.ToString();
 			} catch  {
 				return dataType.FullName;
 			}
 		}
-		protected void loadItem(int i, Group page){
-			if (data [i] == null)//TODO:surely a threading sync problem
+		protected void loadItem(object o, Group page, string _dataTest){
+			if (o == null)//TODO:surely a threading sync problem
 				return;
 			GraphicObject g = null;
 			ItemTemplate iTemp = null;
-			Type dataType = data [i].GetType ();
+			Type dataType = o.GetType ();
 			string itempKey = dataType.FullName;
 
 			if (_dataTest != "TypeOf")
-				itempKey = getItempKey (dataType, data [i]);
+				itempKey = getItempKey (dataType, o, _dataTest);
 
 			if (ItemTemplates.ContainsKey (itempKey))
 				iTemp = ItemTemplates [itempKey];
@@ -437,7 +438,7 @@ namespace Crow
 				(g as Expandable).GetIsExpandable = iTemp.HasSubItems;
 			}
 
-			g.DataSource = data [i];
+			g.DataSource = o;
 		}
 		protected virtual void registerItemClick(GraphicObject g){
 			g.MouseClick += itemClick;
@@ -475,6 +476,13 @@ namespace Crow
 			SelectedIndex = data.IndexOf((sender as GraphicObject).DataSource);
 		}
 
+		bool emitHelperIsAlreadyExpanded (GraphicObject go){
+			if (nodes.Contains (go))
+				return true;
+			nodes.Add (go);
+			return false;
+		}
+
 		protected override void Dispose (bool disposing)
 		{
 			if (disposing && loadingThread != null)
diff --git a/src/Instantiator.cs b/src/Instantiator.cs
index a97f19d2..b01052ca 100644
--- a/src/Instantiator.cs
+++ b/src/Instantiator.cs
@@ -225,7 +225,7 @@ namespace Crow.IML
 		/// <param name="reader">current xml text reader</param>
 		/// <param name="itemTemplatePath">file containing the templates if its a dedicated one</param>
 		string[] parseItemTemplateTag (XmlReader reader, string itemTemplatePath = "") {
-			string dataType = "default", datas = "", path = "";
+			string dataType = "default", datas = "", path = "", dataTest = "TypeOf";
 			while (reader.MoveToNextAttribute ()) {
 				if (reader.Name == "DataType")
 					dataType = reader.Value;
@@ -233,6 +233,8 @@ namespace Crow.IML
 					datas = reader.Value;
 				else if (reader.Name == "Path")
 					path = reader.Value;
+				else if (reader.Name == "DataTest")
+					dataTest = reader.Value;
 			}
 			reader.MoveToElement ();
 
@@ -241,7 +243,7 @@ namespace Crow.IML
 			if (string.IsNullOrEmpty (path)) {
 				itemTmpID += Guid.NewGuid ().ToString ();
 				Interface.Instantiators [itemTmpID] =
-					new ItemTemplate (new MemoryStream (Encoding.UTF8.GetBytes (reader.ReadInnerXml ())), dataType, datas);
+					new ItemTemplate (new MemoryStream (Encoding.UTF8.GetBytes (reader.ReadInnerXml ())), dataTest, dataType, datas);
 
 			} else {
 				if (!reader.IsEmptyElement)
@@ -249,9 +251,9 @@ namespace Crow.IML
 				itemTmpID += path+dataType+datas;
 				if (!Interface.Instantiators.ContainsKey (itemTmpID))
 					Interface.Instantiators [itemTmpID] =
-						new ItemTemplate (Interface.GetStreamFromPath (path), dataType, datas);
+						new ItemTemplate (Interface.GetStreamFromPath (path), dataTest, dataType, datas);
 			}
-			return new string [] { dataType, itemTmpID, datas };
+			return new string [] { dataType, itemTmpID, datas, dataTest };
 		}
 		/// <summary>
 		/// process template and item template definition prior to
@@ -312,7 +314,7 @@ namespace Crow.IML
 												//the file contains a single template to use as default
 												Interface.Instantiators [itemTemplatePath] =
 													new ItemTemplate (itr);
-												itemTemplateIds.Add (new string [] { "default", itemTemplatePath, "" });
+												itemTemplateIds.Add (new string [] { "default", itemTemplatePath, "", "TypeOf" });
 												break;//we should be at the end of the file
 											}
 											itemTemplateIds.Add (parseItemTemplateTag (itr, itemTemplatePath));
@@ -327,7 +329,7 @@ namespace Crow.IML
 					return;
 				//add the default item template if no default is defined
 				if (!itemTemplateIds.Any(ids=>ids[0] == "default"))
-					itemTemplateIds.Add (new string [] { "default", "#Crow.DefaultItem.template", "" });
+					itemTemplateIds.Add (new string [] { "default", "#Crow.DefaultItem.template", "", "TypeOf"});
 				//copy item templates (review this)
 				foreach (string [] iTempId in itemTemplateIds) {
 					ctx.il.Emit (OpCodes.Ldloc_0);//load TempControl ref
diff --git a/src/ItemTemplate.cs b/src/ItemTemplate.cs
index 52bd5207..5ede1d94 100644
--- a/src/ItemTemplate.cs
+++ b/src/ItemTemplate.cs
@@ -52,6 +52,7 @@ namespace Crow
 		public BooleanTestOnInstance HasSubItems;
 		string strDataType;
 		string fetchMethodName;
+		string dataTest;
 
 		#region CTOR
 		/// <summary>
@@ -60,10 +61,11 @@ namespace Crow
 		/// <param name="path">IML file to parse</param>
 		/// <param name="_dataType">type this item will be choosen for, or member of the data item</param>
 		/// <param name="_fetchDataMethod">for hierarchical data, method to call for children fetching</param>
-		public ItemTemplate(string path, string _dataType = null, string _fetchDataMethod = null)
+		public ItemTemplate(string path, string _dataTest = "TypeOf", string _dataType = null, string _fetchDataMethod = null)
 			: base(path) {
 			strDataType = _dataType;
 			fetchMethodName = _fetchDataMethod;
+			dataTest = _dataTest;
 
 		}
 		/// <summary>
@@ -72,11 +74,12 @@ namespace Crow
 		/// <param name="path">IML fragment to parse</param>
 		/// <param name="_dataType">type this item will be choosen for, or member of the data item</param>
 		/// <param name="_fetchDataMethod">for hierarchical data, method to call for children fetching</param>
-		public ItemTemplate (Stream ImlFragment, string _dataType, string _fetchDataMethod)
+		public ItemTemplate (Stream ImlFragment, string _dataTest, string _dataType, string _fetchDataMethod)
 			:base(ImlFragment)
 		{
 			strDataType = _dataType;
 			fetchMethodName = _fetchDataMethod;
+			dataTest = _dataTest;
 		}
 		/// <summary>
 		/// Initializes a new instance of the <see cref="Crow.ItemTemplate"/> class using the opened XmlReader in args.
@@ -84,11 +87,12 @@ namespace Crow
 		/// <param name="path">XML reader positionned before or at the root node</param>
 		/// <param name="_dataType">type this item will be choosen for, or member of the data item</param>
 		/// <param name="_fetchDataMethod">for hierarchical data, method to call for children fetching</param>
-		public ItemTemplate (XmlReader reader, string _dataType = null, string _fetchDataMethod = null)
+		public ItemTemplate (XmlReader reader, string _dataTest = "TypeOf" , string _dataType = null, string _fetchDataMethod = null)
 			:base(reader)
 		{
 			strDataType = _dataType;
 			fetchMethodName = _fetchDataMethod;
+			dataTest = _dataTest;
 		}
 		#endregion
 
@@ -108,7 +112,7 @@ namespace Crow
 			Type tmpGrpType = typeof(TemplatedGroup);
 			Type evtType = typeof(EventHandler);
 
-			PropertyInfo piData = tmpGrpType.GetProperty ("Data");
+			//PropertyInfo piData = tmpGrpType.GetProperty ("Data");
 
 			MethodInfo evtInvoke = evtType.GetMethod ("Invoke");
 			ParameterInfo [] evtParams = evtInvoke.GetParameters ();
@@ -120,41 +124,55 @@ namespace Crow
 			//DM is bound to templatedGroup root (arg0)
 			//arg1 is the sender of the expand event
 			DynamicMethod dm = new DynamicMethod ("dyn_expand_" + fetchMethodName,
-				typeof (void), args, true);
+				typeof (void), args,typeof(TemplatedGroup), true);
 
 			System.Reflection.Emit.Label gotoEnd;
 			System.Reflection.Emit.Label ifDataIsNull;
+			System.Reflection.Emit.Label gotoItemsContainerNotFound;
 
 			ILGenerator il = dm.GetILGenerator (256);
 			il.DeclareLocal(typeof(GraphicObject));
 
 			gotoEnd = il.DefineLabel ();
 			ifDataIsNull = il.DefineLabel ();
+			gotoItemsContainerNotFound = il.DefineLabel ();
 
 			il.Emit (OpCodes.Ldarg_1);//load sender of expand event
-
-			il.Emit(OpCodes.Ldstr, "List");
+			il.Emit(OpCodes.Ldstr, "ItemsContainer");//load name to find
 			il.Emit (OpCodes.Callvirt, CompilerServices.miFindByName);
-			il.Emit (OpCodes.Stloc_0);
+			il.Emit (OpCodes.Stloc_0);//save items container as loc0
 
-			//check that 'Data' of list is not already set
+			//ensure ItemsContainer is not null
 			il.Emit (OpCodes.Ldloc_0);
-			il.Emit (OpCodes.Callvirt, piData.GetGetMethod ());
-			il.Emit (OpCodes.Brfalse, ifDataIsNull);
-			il.Emit (OpCodes.Br, gotoEnd);
+			il.Emit (OpCodes.Brfalse, gotoItemsContainerNotFound);
+
+			//check that node is not already expanded
+			il.Emit (OpCodes.Ldarg_0);//push root TemplatedGroup into the stack
+			il.Emit (OpCodes.Ldarg_1);
+			il.Emit (OpCodes.Call, CompilerServices.miIsAlreadyExpanded);
+			il.Emit (OpCodes.Brtrue, gotoEnd);
+//			il.Emit (OpCodes.Ldloc_0);
+//			il.Emit (OpCodes.Callvirt, piData.GetGetMethod ());
+//			il.Emit (OpCodes.Brfalse, ifDataIsNull);
+//			il.Emit (OpCodes.Br, gotoEnd);
+
+//			il.MarkLabel(ifDataIsNull);
 
-			il.MarkLabel(ifDataIsNull);
 			//copy the ref of ItemTemplates list TODO: maybe find another way to share it among the nodes?
-			FieldInfo fiTemplates = tmpGrpType.GetField("ItemTemplates");
-			il.Emit (OpCodes.Ldloc_0);
-			il.Emit (OpCodes.Ldarg_0);
-			il.Emit (OpCodes.Ldfld, fiTemplates);
-			il.Emit (OpCodes.Stfld, fiTemplates);
+//			FieldInfo fiTemplates = tmpGrpType.GetField("ItemTemplates");
+//			il.Emit (OpCodes.Ldloc_0);
+//			il.Emit (OpCodes.Ldarg_0);
+//			il.Emit (OpCodes.Ldfld, fiTemplates);
+//			il.Emit (OpCodes.Stfld, fiTemplates);
 
 			//call 'fetchMethodName' from the dataSource to build the sub nodes list
-			il.Emit (OpCodes.Ldloc_0);//push 'List' (of sub nodes) into the stack
-			il.Emit (OpCodes.Ldarg_1);//get the dataSource of the sender
-			il.Emit (OpCodes.Callvirt, CompilerServices.miGetDataSource);
+			//il.Emit (OpCodes.Ldarg_0);//load root templatedGroop
+
+			il.Emit (OpCodes.Ldarg_0);//push root TemplatedGroup into the stack
+			il.Emit (OpCodes.Ldarg_1);//load sender node of expand
+			il.Emit (OpCodes.Callvirt, CompilerServices.miGetDataSource);//get the dataSource of the sender
+
+
 
 			if (fetchMethodName != "self") {//special keyword self allows the use of recurent list<<<
 				if (dataType == null) {
@@ -167,7 +185,15 @@ namespace Crow
 					emitGetSubData(il, dataType);			
 			}
 			//set 'return' from the fetch method as 'data' of the list
-			il.Emit (OpCodes.Callvirt, piData.GetSetMethod ());
+			//il.Emit (OpCodes.Callvirt, piData.GetSetMethod ());
+			il.Emit (OpCodes.Ldloc_0);//load second arg of loadPage, the sender node
+			il.Emit (OpCodes.Ldstr, dataTest);//load 3rd arg, dataTest kind on subitems
+			il.Emit (OpCodes.Callvirt, CompilerServices.miLoadPage);
+			il.Emit (OpCodes.Br, gotoEnd);
+
+			il.MarkLabel(gotoItemsContainerNotFound);
+			il.EmitWriteLine("ItemsContainer not found in ItemTemplate for " + host.ToString());
+
 
 			il.MarkLabel(gotoEnd);
 			il.Emit (OpCodes.Ret);
@@ -203,7 +229,6 @@ namespace Crow
 			HasSubItems = (BooleanTestOnInstance)dm.CreateDelegate (typeof(BooleanTestOnInstance));
 			#endregion
 		}
-
 		//data is on the stack
 		void emitGetSubData(ILGenerator il, Type dataType){
 			MethodInfo miGetDatas = dataType.GetMethod (fetchMethodName, new Type[] {});
-- 
2.47.3