Added logical tree extension methods.

Perspex.SceneGraph/LogicalTree/LogicalExtensions.cs

@@ -0,0 +1,80 @@
+// -----------------------------------------------------------------------
+// <copyright file="LogicalExtensions.cs" company="Steven Kirk">
+// Copyright 2014 MIT Licence. See licence.md for more information.
+// </copyright>
+// -----------------------------------------------------------------------
+
+namespace Perspex.LogicalTree
+{
+    using System;
+    using System.Collections.Generic;
+    using System.Linq;
+
+    public static class LogicalExtensions
+    {
+        public static IEnumerable<ILogical> GetLogicalAncestors(this ILogical logical)
+        {
+            Contract.Requires<NullReferenceException>(logical != null);
+
+            logical = logical.LogicalParent;
+
+            while (logical != null)
+            {
+                yield return logical;
+                logical = logical.LogicalParent;
+            }
+        }
+
+        public static IEnumerable<ILogical> GetSelfAndLogicalAncestors(this ILogical logical)
+        {
+            yield return logical;
+
+            foreach (var ancestor in logical.GetLogicalAncestors())
+            {
+                yield return ancestor;
+            }
+        }
+
+       
+        public static IEnumerable<ILogical> GetLogicalChildren(this ILogical logical)
+        {
+            return logical.LogicalChildren;
+        }
+
+        public static IEnumerable<ILogical> GetLogicalDescendents(this ILogical logical)
+        {
+            foreach (ILogical child in logical.LogicalChildren)
+            {
+                yield return child;
+
+                foreach (ILogical descendent in child.GetLogicalDescendents())
+                {
+                    yield return descendent;
+                }
+            }
+        }
+
+        public static ILogical GetLogicalParent(this ILogical logical)
+        {
+            return logical.LogicalParent;
+        }
+
+        public static T GetLogicalParent<T>(this ILogical logical) where T : class
+        {
+            return logical.LogicalParent as T;
+        }
+
+        public static IEnumerable<ILogical> GetLogicalSiblings(this ILogical logical)
+        {
+            ILogical parent = logical.LogicalParent;
+
+            if (parent != null)
+            {
+                foreach (ILogical sibling in parent.LogicalChildren)
+                {
+                    yield return sibling;
+                }
+            }
+        }
+    }
+}

Perspex.SceneGraph/Perspex.SceneGraph.csproj

@@ -92,6 +92,7 @@
     <Compile Include="Thickness.cs" />
     <Compile Include="Vector.cs" />
     <Compile Include="Visual.cs" />
+    <Compile Include="LogicalTree\LogicalExtensions.cs" />
     <Compile Include="VisualTree\VisualExtensions.cs" />
   </ItemGroup>
   <ItemGroup>