[C] Lookup in RD also lookup in merged RDs (#861)

3 files changed, 58 insertions, 9 deletions

diff --git a/Xamarin.Forms.Core.UnitTests/ResourceDictionaryTests.cs b/Xamarin.Forms.Core.UnitTests/ResourceDictionaryTests.cs
index 3621d955..d1a43732 100644
--- a/Xamarin.Forms.Core.UnitTests/ResourceDictionaryTests.cs
+++ b/Xamarin.Forms.Core.UnitTests/ResourceDictionaryTests.cs
@@ -290,7 +290,7 @@ namespace Xamarin.Forms.Core.UnitTests
 			rd0.MergedWith = typeof(MyRD);
 
 			object _;
-			Assert.True(rd0.TryGetMergedValue("foo", out _));
+			Assert.True(rd0.TryGetValue("foo", out _));
 			Assert.AreEqual("Foo", _);
 		}
 
@@ -307,5 +307,56 @@ namespace Xamarin.Forms.Core.UnitTests
 			}
 			Assert.Fail();
 		}
+
+		[Test]
+		public void ContainsReturnsValuesForMergedRD()
+		{
+			var rd = new ResourceDictionary {
+				{"baz", "BAZ"},
+				{"qux", "QUX"},
+			};
+			rd.MergedWith = typeof(MyRD);
+
+			Assert.That(rd.Contains(new KeyValuePair<string, object>("foo", "Foo")), Is.True);
+		}
+
+		[Test]
+		public void CountDoesNotIncludeMerged()
+		{
+			var rd = new ResourceDictionary {
+				{"baz", "Baz"},
+				{"qux", "Qux"},
+			};
+			rd.MergedWith = typeof(MyRD);
+
+			Assert.That(rd.Count, Is.EqualTo(2));
+		}
+
+		[Test]
+		public void IndexerLookupInMerged()
+		{
+			var rd = new ResourceDictionary {
+				{"baz", "BAZ"},
+				{"qux", "QUX"},
+			};
+			rd.MergedWith = typeof(MyRD);
+
+			Assert.That(() => rd["foo"], Throws.Nothing);
+			Assert.That(rd["foo"], Is.EqualTo("Foo"));
+		}
+
+		[Test]
+		public void TryGetValueLookupInMerged()
+		{
+			var rd = new ResourceDictionary { 
+				{"baz", "BAZ"},
+				{"qux", "QUX"},
+			};
+			rd.MergedWith = typeof(MyRD);
+
+			object _;
+			Assert.That(rd.TryGetValue("foo", out _), Is.True);
+			Assert.That(rd.TryGetValue("baz", out _), Is.True);
+}
 	}
 }
\ No newline at end of file
diff --git a/Xamarin.Forms.Core/ResourceDictionary.cs b/Xamarin.Forms.Core/ResourceDictionary.cs
index c9413eb3..2fc11ffc 100644
--- a/Xamarin.Forms.Core/ResourceDictionary.cs
+++ b/Xamarin.Forms.Core/ResourceDictionary.cs
@@ -48,7 +48,8 @@ namespace Xamarin.Forms
 
 		bool ICollection<KeyValuePair<string, object>>.Contains(KeyValuePair<string, object> item)
 		{
-			return ((ICollection<KeyValuePair<string, object>>)_innerDictionary).Contains(item);
+			return ((ICollection<KeyValuePair<string, object>>)_innerDictionary).Contains(item)
+				|| (_mergedInstance != null && _mergedInstance.Contains(item));
 		}
 
 		void ICollection<KeyValuePair<string, object>>.CopyTo(KeyValuePair<string, object>[] array, int arrayIndex)
@@ -91,6 +92,8 @@ namespace Xamarin.Forms
 			{
 				if (_innerDictionary.ContainsKey(index))
 					return _innerDictionary[index];
+				if (_mergedInstance != null && _mergedInstance.ContainsKey(index))
+					return _mergedInstance[index];
 				throw new KeyNotFoundException($"The resource '{index}' is not present in the dictionary.");
 			}
 			set
@@ -137,11 +140,6 @@ namespace Xamarin.Forms
 
 		public bool TryGetValue(string key, out object value)
 		{
-			return _innerDictionary.TryGetValue(key, out value);
-		}
-
-		internal bool TryGetMergedValue(string key, out object value)
-		{
 			return _innerDictionary.TryGetValue(key, out value) || (_mergedInstance != null && _mergedInstance.TryGetValue(key, out value));
 		}
 
diff --git a/Xamarin.Forms.Xaml/MarkupExtensions/StaticResourceExtension.cs b/Xamarin.Forms.Xaml/MarkupExtensions/StaticResourceExtension.cs
index 16c80533..14e0b8be 100644
--- a/Xamarin.Forms.Xaml/MarkupExtensions/StaticResourceExtension.cs
+++ b/Xamarin.Forms.Xaml/MarkupExtensions/StaticResourceExtension.cs
@@ -31,7 +31,7 @@ namespace Xamarin.Forms.Xaml
 				var resDict = ve?.Resources ?? p as ResourceDictionary;
 				if (resDict == null)
 					continue;
-				if (resDict.TryGetMergedValue(Key, out resource))
+				if (resDict.TryGetValue(Key, out resource))
 					break;
 			}
 			resource = resource ?? GetApplicationLevelResource(Key, xmlLineInfo);
@@ -59,7 +59,7 @@ namespace Xamarin.Forms.Xaml
 		internal object GetApplicationLevelResource(string key, IXmlLineInfo xmlLineInfo)
 		{
 			object resource;
-			if (Application.Current == null || Application.Current.Resources == null || !Application.Current.Resources.TryGetMergedValue(Key, out resource))
+			if (Application.Current == null || Application.Current.Resources == null || !Application.Current.Resources.TryGetValue(Key, out resource))
 				throw new XamlParseException($"StaticResource not found for key {Key}", xmlLineInfo);
 			return resource;
 		}