Adding test

tests/Avalonia.Markup.UnitTests/Data/MultiBindingTests.cs

@@ -157,6 +157,29 @@ namespace Avalonia.Markup.UnitTests.Data
             Assert.Equal("1,2,Fallback", target.Text);
         }
 
+        [Fact]
+        public void MultiBinding_Without_StringFormat_And_Converter()
+        {
+            var source = new { A = 1, B = 2, C = 3 };
+            var target = new ItemsControl {  };
+
+            var binding = new MultiBinding
+            {                
+                Bindings = new[]
+                {
+                    new Binding { Path = "A", Source = source },
+                    new Binding { Path = "B", Source = source },
+                    new Binding { Path = "C", Source = source },
+                },
+            };
+
+            target.Bind(ItemsControl.ItemsProperty, binding);
+            Assert.Equal(target.ItemCount, 3);
+            Assert.Equal(target.Items.ElementAt(0), source.A);
+            Assert.Equal(target.Items.ElementAt(1), source.B);
+            Assert.Equal(target.Items.ElementAt(2), source.C);
+        }
+
         private class ConcatConverter : IMultiValueConverter
         {
             public object Convert(IList<object> values, Type targetType, object parameter, CultureInfo culture)

tests/Avalonia.Markup.UnitTests/Extensions/IEnummerableExtension.cs

@@ -0,0 +1,21 @@
+using System;
+using System.Collections;
+
+namespace Avalonia.Markup.UnitTests
+{
+    static class IEnummerableExtension
+    {
+        public static object ElementAt(this IEnumerable source, int index)
+        {
+            var i = -1;
+            var enumerator = source.GetEnumerator();
+
+            while (enumerator.MoveNext() && ++i < index);
+            if (i == index)
+            {
+                return enumerator.Current;
+            }
+            throw new ArgumentOutOfRangeException(nameof(index));
+        }
+    }
+}