Can now bind to a non-IList/Array indexer (with any parameter type convertible via TypeUtilities).

src/Markup/Perspex.Markup/Data/IndexerNode.cs

@@ -1,10 +1,12 @@
 // Copyright (c) The Perspex Project. All rights reserved.
 // Licensed under the MIT license. See licence.md file in the project root for full license information.
 
+using Perspex.Utilities;
 using System;
 using System.Collections;
 using System.Collections.Generic;
 using System.Collections.Specialized;
+using System.Globalization;
 using System.Linq;
 using System.Reflection;
 
@@ -104,6 +106,34 @@ namespace Perspex.Markup.Data
                     return list[_intArgs[0]];
                 }
             }
+            else
+            {
+                PropertyInfo indexerProperty = null;
+                ParameterInfo[] indexerParameters = null;
+                foreach (var property in typeInfo.DeclaredProperties)
+                {
+                    var indexParams = property.GetIndexParameters();
+                    if (indexParams.Length > 0)
+                    {
+                        indexerProperty = property;
+                        indexerParameters = indexParams;
+                    }
+                }
+                if (indexerProperty != null && indexerParameters.Length == Arguments.Count)
+                {
+                    var convertedObjectArray = new object[indexerParameters.Length];
+                    for (int i = 0; i < Arguments.Count; i++)
+                    {
+                        object temp = null;
+                        if (!TypeUtilities.TryConvert(indexerParameters[i].ParameterType, Arguments[i], CultureInfo.InvariantCulture, out temp))
+                        {
+                            return PerspexProperty.UnsetValue;
+                        }
+                        convertedObjectArray[i] = temp;
+                    }
+                    return indexerProperty.GetValue(target, convertedObjectArray);
+                }
+            }
 
             return PerspexProperty.UnsetValue;
         }

src/Markup/Perspex.Markup/Data/Parsers/ArgumentListParser.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Text;
 
 namespace Perspex.Markup.Data.Parsers
 {
@@ -26,7 +27,12 @@ namespace Perspex.Markup.Data.Parsers
                     }
                     else
                     {
-                        throw new ExpressionParseException(r.Position, "Expected integer.");
+                        var builder = new StringBuilder();
+                        while (!r.End && r.Peek != ',' && r.Peek != close)
+                        {
+                            builder.Append(r.Take());
+                        }
+                        result.Add(builder.ToString());
                     }
 
                     r.SkipWhitespace();

tests/Perspex.Markup.UnitTests/Data/ExpressionObserverTests_Indexer.cs

@@ -32,6 +32,16 @@ namespace Perspex.Markup.UnitTests.Data
             Assert.Equal("qux", result);
         }
 
+        [Fact]
+        public async void Should_Get_Value_For_Non_Integer_Indexer()
+        {
+            var data = new { Foo = new Dictionary<string, string> { { "foo", "bar" }, { "baz", "qux" } } };
+            var target = new ExpressionObserver(data, "Foo[foo]");
+            var result = await target.Take(1);
+
+            Assert.Equal("bar", result);
+        }
+
         [Fact]
         public async void Array_Out_Of_Bounds_Should_Return_UnsetValue()
         {