Improve KVP ConvertTo support

Author: mythz

src/ServiceStack.Text/AutoMappingUtils.cs

@@ -776,6 +776,25 @@ public static object TryConvertCollections(Type fromType, Type toType, object fr
         {
             if (fromValue is IEnumerable values)
             {
+                var toEnumObjs = toType == typeof(IEnumerable<object>);
+                if (typeof(IList).IsAssignableFrom(toType) || toEnumObjs)
+                {
+                    var to = (IList) (toType.IsArray || toEnumObjs ? new List<object>() : toType.CreateInstance());
+                    var elType = toType.GetCollectionType();
+                    foreach (var item in values)
+                    {
+                        to.Add(elType != null ? item.ConvertTo(elType) : item);
+                    }
+                    if (elType != null && toType.IsArray)
+                    {
+                        var arr = Array.CreateInstance(elType, to.Count);
+                        to.CopyTo(arr, 0);
+                        return arr;
+                    }
+                    
+                    return to;
+                }
+                
                 if (fromValue is IDictionary d)
                 {
                     var obj = toType.CreateInstance();
@@ -784,18 +803,14 @@ public static object TryConvertCollections(Type fromType, Type toType, object fr
                         case List<KeyValuePair<string, string>> toList: {
                             foreach (var key in d.Keys)
                             {
-                                var toKey = key.ConvertTo<string>();
-                                var toValue = d[key].ConvertTo<string>();
-                                toList.Add(new KeyValuePair<string, string>(toKey, toValue));
+                                toList.Add(new KeyValuePair<string, string>(key.ConvertTo<string>(), d[key].ConvertTo<string>()));
                             }
                             return toList;
                         }
                         case List<KeyValuePair<string, object>> toObjList: {
                             foreach (var key in d.Keys)
                             {
-                                var toKey = key.ConvertTo<string>();
-                                var toValue = d[key];
-                                toObjList.Add(new KeyValuePair<string, object>(toKey, toValue));
+                                toObjList.Add(new KeyValuePair<string, object>(key.ConvertTo<string>(), d[key]));
                             }
                             return toObjList;
                         }

src/ServiceStack.Text/PlatformExtensions.cs

@@ -791,7 +791,7 @@ public static bool GetKeyValuePairsTypes(this Type dictType, out Type keyType, o
             return false;
         }
 
-        private static bool GetKeyValuePairTypes(this Type kvpType, out Type keyType, out Type valueType)
+        public static bool GetKeyValuePairTypes(this Type kvpType, out Type keyType, out Type valueType)
         {
             var genericKvps = kvpType.GetTypeWithGenericTypeDefinitionOf(typeof(KeyValuePair<,>));
             if (genericKvps != null)

tests/ServiceStack.Text.Tests/AutoMappingTests.cs

@@ -1283,5 +1283,62 @@ public void Can_convert_KVPs_to_ObjectDictionary()
             Assert.That(new[] { strKvp, strKvp2 }.ConvertTo<Dictionary<string,object>>(), Is.EquivalentTo(new Dictionary<string, object> { {"A", "1"}, {"B", "2"} }));
             Assert.That(new[] { intKvp, intKvp2 }.ConvertTo<Dictionary<string,object>>(), Is.EquivalentTo(new Dictionary<string, object> { {"A", 1}, {"B", 2} }));
         }
+
+        [Test]
+        public void Can_convert_between_KVP_Objects_and_IEnumerable()
+        {
+            var kvps = new List<KeyValuePair<string, object>> {
+                new KeyValuePair<string, object>("A", 1),
+                new KeyValuePair<string, object>("B", 2),
+                new KeyValuePair<string, object>("C", 3),
+            };
+            
+            Assert.That(kvps.ConvertTo<IEnumerable<object>>(), Is.EqualTo(kvps));
+            Assert.That(kvps.ConvertTo<List<object>>(), Is.EqualTo(kvps));
+            Assert.That(kvps.ConvertTo<object[]>(), Is.EqualTo(kvps));
+
+            List<object> listObjs = kvps.Cast<object>().ToList();
+            Assert.That(listObjs.ConvertTo<List<KeyValuePair<string, object>>>(), Is.EquivalentTo(listObjs));
+            object[] arrayObjs = kvps.Cast<object>().ToArray();
+            Assert.That(arrayObjs.ConvertTo<List<KeyValuePair<string, object>>>(), Is.EquivalentTo(arrayObjs));
+        }
+
+        [Test]
+        public void Can_convert_between_KVP_Strings_and_IEnumerable()
+        {
+            var kvps = new List<KeyValuePair<string, string>> {
+                new KeyValuePair<string, string>("A", "1"),
+                new KeyValuePair<string, string>("B", "2"),
+                new KeyValuePair<string, string>("C", "3"),
+            };
+            
+            Assert.That(kvps.ConvertTo<IEnumerable<object>>(), Is.EqualTo(kvps));
+            Assert.That(kvps.ConvertTo<List<object>>(), Is.EqualTo(kvps));
+            Assert.That(kvps.ConvertTo<object[]>(), Is.EqualTo(kvps));
+
+            List<object> listObjs = kvps.Cast<object>().ToList();
+            Assert.That(listObjs.ConvertTo<List<KeyValuePair<string, object>>>(), Is.EquivalentTo(listObjs));
+            object[] arrayObjs = kvps.Cast<object>().ToArray();
+            Assert.That(arrayObjs.ConvertTo<List<KeyValuePair<string, object>>>(), Is.EquivalentTo(arrayObjs));
+        }
+
+        [Test]
+        public void Can_convert_between_KVP_ints_and_IEnumerable()
+        {
+            var kvps = new List<KeyValuePair<string, int>> {
+                new KeyValuePair<string, int>("A", 1),
+                new KeyValuePair<string, int>("B", 2),
+                new KeyValuePair<string, int>("C", 3),
+            };
+            
+            Assert.That(kvps.ConvertTo<IEnumerable<object>>(), Is.EqualTo(kvps));
+            Assert.That(kvps.ConvertTo<List<object>>(), Is.EqualTo(kvps));
+            Assert.That(kvps.ConvertTo<object[]>(), Is.EqualTo(kvps));
+
+            List<object> listObjs = kvps.Cast<object>().ToList();
+            Assert.That(listObjs.ConvertTo<List<KeyValuePair<string, object>>>(), Is.EquivalentTo(listObjs));
+            object[] arrayObjs = kvps.Cast<object>().ToArray();
+            Assert.That(arrayObjs.ConvertTo<List<KeyValuePair<string, object>>>(), Is.EquivalentTo(arrayObjs));
+        }
     }
 }