-Added NullValueHandling and DefaultValueHandling support to serializing dynamic properties

Src/Newtonsoft.Json.Tests/Serialization/DynamicTests.cs

@@ -250,6 +250,78 @@ namespace Newtonsoft.Json.Tests.Serialization
 
       Assert.AreEqual(false, foo.Values["retweeted"]);
     }
+
+    [Test]
+    public void SerializeDynamicObjectWithNullValueHandlingIgnore()
+    {
+      dynamic o = new TestDynamicObject();
+      o.Text = "Text!";
+      o.Int = int.MaxValue;
+      o.ChildObject = null; // Tests an explicitly defined property of a dynamic object with a null value.
+      o.DynamicChildObject = null; // vs. a completely dynamic defined property.
+
+      string json = JsonConvert.SerializeObject(o, Formatting.Indented, new JsonSerializerSettings
+        {
+          NullValueHandling = NullValueHandling.Ignore,
+        });
+
+      Console.WriteLine(json);
+
+      Assert.AreEqual(@"{
+  ""Explicit"": false,
+  ""Text"": ""Text!"",
+  ""Int"": 2147483647
+}", json);
+    }
+
+    [Test]
+    public void SerializeDynamicObjectWithNullValueHandlingInclude()
+    {
+      dynamic o = new TestDynamicObject();
+      o.Text = "Text!";
+      o.Int = int.MaxValue;
+      o.ChildObject = null; // Tests an explicitly defined property of a dynamic object with a null value.
+      o.DynamicChildObject = null; // vs. a completely dynamic defined property.
+
+      string json = JsonConvert.SerializeObject(o, Formatting.Indented, new JsonSerializerSettings
+        {
+          NullValueHandling = NullValueHandling.Include,
+        });
+
+      Console.WriteLine(json);
+
+      Assert.AreEqual(@"{
+  ""Explicit"": false,
+  ""Text"": ""Text!"",
+  ""DynamicChildObject"": null,
+  ""Int"": 2147483647,
+  ""ChildObject"": null
+}", json);
+    }
+
+    [Test]
+    public void SerializeDynamicObjectWithDefaultValueHandlingIgnore()
+    {
+      dynamic o = new TestDynamicObject();
+      o.Text = "Text!";
+      o.Int = int.MaxValue;
+      o.IntDefault = 0;
+      o.NUllableIntDefault = default(int?);
+      o.ChildObject = null; // Tests an explicitly defined property of a dynamic object with a null value.
+      o.DynamicChildObject = null; // vs. a completely dynamic defined property.
+
+      string json = JsonConvert.SerializeObject(o, Formatting.Indented, new JsonSerializerSettings
+      {
+        DefaultValueHandling = DefaultValueHandling.Ignore,
+      });
+
+      Console.WriteLine(json);
+
+      Assert.AreEqual(@"{
+  ""Text"": ""Text!"",
+  ""Int"": 2147483647
+}", json);
+    }
   }
 
   public class DynamicChildObject

Src/Newtonsoft.Json/Serialization/JsonSerializerInternalWriter.cs

@@ -757,6 +757,9 @@ To fix this error either change the environment to be fully trusted, change the
           {
             JsonContract valueContract = GetContractSafe(memberValue);
 
+            if (!ShouldWriteDynamicProperty(memberValue))
+              continue;
+
             if (CheckForCircularReference(writer, memberValue, null, valueContract, contract, member))
             {
               string resolvedPropertyName = (contract.PropertyNameResolver != null)
@@ -784,6 +787,18 @@ To fix this error either change the environment to be fully trusted, change the
     }
 #endif
 
+    private bool ShouldWriteDynamicProperty(object memberValue)
+    {
+      if (Serializer._nullValueHandling == NullValueHandling.Ignore && memberValue == null)
+        return false;
+
+      if (HasFlag(Serializer._defaultValueHandling, DefaultValueHandling.Ignore) &&
+        (memberValue == null || MiscellaneousUtils.ValueEquals(memberValue, ReflectionUtils.GetDefaultValue(memberValue.GetType()))))
+        return false;
+
+      return true;
+    }
+
     private bool ShouldWriteType(TypeNameHandling typeNameHandlingFlag, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerProperty)
     {
       TypeNameHandling resolvedTypeNameHandling =