Added parent selector.

Perspex.Styling/Selectors.cs

@@ -59,6 +59,13 @@ namespace Perspex.Styling
             return previous.OfType(typeof(T));
         }
 
+        public static Selector Parent(this Selector previous)
+        {
+            Contract.Requires<ArgumentNullException>(previous != null);
+
+            return new Selector(previous, x => MatchParent(x, previous), " < ", stopTraversal: true);
+        }
+
         public static Selector Template(this Selector previous)
         {
             Contract.Requires<ArgumentNullException>(previous != null);
@@ -128,6 +135,12 @@ namespace Perspex.Styling
             return new SelectorMatch(controlType == type);
         }
 
+        private static SelectorMatch MatchParent(IStyleable control, Selector previous)
+        {
+            var parent = ((ILogical)control).LogicalParent;
+            return previous.Match((IStyleable)parent);
+        }
+
         private static SelectorMatch MatchTemplate(IStyleable control, Selector previous)
         {
             IStyleable templatedParent = control.TemplatedParent as IStyleable;

Tests/Perspex.Styling.UnitTests/Perspex.Styling.UnitTests.csproj

@@ -83,6 +83,7 @@
   <ItemGroup>
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="SelectorTests_Class.cs" />
+    <Compile Include="SelectorTests_Parent.cs" />
     <Compile Include="SelectorTests_Descendent.cs" />
     <Compile Include="SelectorTests_Name.cs" />
     <Compile Include="SelectorTests_Multiple.cs" />

Tests/Perspex.Styling.UnitTests/SelectorTests_Parent.cs

@@ -0,0 +1,102 @@
+// -----------------------------------------------------------------------
+// <copyright file="SelectorTests_Descendent.cs" company="Steven Kirk">
+// Copyright 2014 MIT Licence. See licence.md for more information.
+// </copyright>
+// -----------------------------------------------------------------------
+
+namespace Perspex.Styling.UnitTests
+{
+    using System;
+    using System.Linq;
+    using System.Reactive.Linq;
+    using System.Threading.Tasks;
+    using Perspex.Collections;
+    using Perspex.Styling;
+    using Xunit;
+
+    public class SelectorTests_Parent
+    {
+        [Fact]
+        public void Parent_Matches_Control_When_It_Is_Child_OfType()
+        {
+            var parent = new TestLogical1();
+            var child = new TestLogical2();
+
+            child.LogicalParent = parent;
+
+            var selector = new Selector().OfType<TestLogical1>().Parent().OfType<TestLogical2>();
+
+            Assert.True(selector.Match(child).ImmediateResult);
+        }
+
+        [Fact]
+        public void Parent_Doesnt_Match_Control_When_It_Is_Grandchild_OfType()
+        {
+            var grandparent = new TestLogical1();
+            var parent = new TestLogical2();
+            var child = new TestLogical3();
+
+            parent.LogicalParent = grandparent;
+            child.LogicalParent = parent;
+
+            var selector = new Selector().OfType<TestLogical1>().Parent().OfType<TestLogical3>();
+
+            Assert.False(selector.Match(child).ImmediateResult);
+        }
+
+        [Fact]
+        public async Task Parent_Matches_Control_When_It_Is_Child_OfType_And_Class()
+        {
+            var parent = new TestLogical1();
+            var child = new TestLogical2();
+
+            child.LogicalParent = parent;
+
+            var selector = new Selector().OfType<TestLogical1>().Class("foo").Parent().OfType<TestLogical2>();
+            var activator = selector.Match(child).ObservableResult;
+
+            Assert.False(await activator.Take(1));
+            parent.Classes.Add("foo");
+            Assert.True(await activator.Take(1));
+            parent.Classes.Remove("foo");
+            Assert.False(await activator.Take(1));
+        }
+
+        public abstract class TestLogical : ILogical, IStyleable
+        {
+            public TestLogical()
+            {
+                this.Classes = new Classes();
+            }
+
+            public Classes Classes { get; }
+            public string Name { get; set; }
+            public IPerspexReadOnlyList<ILogical> LogicalChildren { get; set; }
+            public ILogical LogicalParent { get; set; }
+            public Type StyleKey { get; }
+            public ITemplatedControl TemplatedParent { get; }
+
+            public IDisposable Bind(PerspexProperty property, IObservable<object> source, BindingPriority priority)
+            {
+                throw new NotImplementedException();
+            }
+
+            public void SetValue(PerspexProperty property, object value, BindingPriority priority)
+            {
+                throw new NotImplementedException();
+            }
+        }
+
+        public class TestLogical1 : TestLogical
+        {
+        }
+
+        public class TestLogical2 : TestLogical
+        {
+        }
+
+        public class TestLogical3 : TestLogical
+        {
+        }
+    }
+}