-Added ItemNullValueHandling to JsonObjectContract

Src/Newtonsoft.Json/JsonObjectAttribute.cs

@@ -51,9 +51,9 @@ namespace Newtonsoft.Json
         }
 
         /// <summary>
-        /// Gets or sets the null value handling.
+        /// Gets or sets how the object's properties with null values are handled during serialization and deserialization.
         /// </summary>
-        /// <value>The null value handling.</value>
+        /// <value>How the object's properties with null values are handled during serialization and deserialization.</value>
         public NullValueHandling ItemNullValueHandling
         {
             get => _itemNullValueHandling ?? default(NullValueHandling);

Src/Newtonsoft.Json/Serialization/DefaultContractResolver.cs

@@ -327,6 +327,8 @@ namespace Newtonsoft.Json.Serialization
             if (attribute != null)
             {
                 contract.ItemRequired = attribute._itemRequired;
+                contract.ItemNullValueHandling = attribute._itemNullValueHandling;
+
                 if (attribute.NamingStrategyType != null)
                 {
                     NamingStrategy namingStrategy = JsonTypeReflector.GetContainerNamingStrategy(attribute);
@@ -1509,11 +1511,6 @@ namespace Newtonsoft.Json.Serialization
 #endif
             }
 
-            if (property.NullValueHandling == null && containerAttribute is JsonObjectAttribute objectAttribute)
-            {
-                property.NullValueHandling = objectAttribute._itemNullValueHandling;
-            }
-
             if (requiredAttribute != null)
             {
                 property._required = Required.Always;

Src/Newtonsoft.Json/Serialization/JsonObjectContract.cs

@@ -52,6 +52,12 @@ namespace Newtonsoft.Json.Serialization
         /// </value>
         public Required? ItemRequired { get; set; }
 
+        /// <summary>
+        /// Gets or sets how the object's properties with null values are handled during serialization and deserialization.
+        /// </summary>
+        /// <value>How the object's properties with null values are handled during serialization and deserialization.</value>
+        public NullValueHandling? ItemNullValueHandling { get; set; }
+
         /// <summary>
         /// Gets the object's properties.
         /// </summary>

Src/Newtonsoft.Json/Serialization/JsonSerializerInternalBase.cs

@@ -81,6 +81,16 @@ namespace Newtonsoft.Json.Serialization
             }
         }
 
+        protected NullValueHandling ResolvedNullValueHandling(JsonObjectContract containerContract, JsonProperty property)
+        {
+            NullValueHandling resolvedNullValueHandling =
+                property.NullValueHandling
+                ?? containerContract?.ItemNullValueHandling
+                ?? Serializer._nullValueHandling;
+
+            return resolvedNullValueHandling;
+        }
+
         private ErrorContext GetErrorContext(object currentObject, object member, string path, Exception error)
         {
             if (_currentErrorContext == null)

Src/Newtonsoft.Json/Serialization/JsonSerializerInternalReader.cs

@@ -1012,7 +1012,7 @@ namespace Newtonsoft.Json.Serialization
             // otherwise also set it if CreateValue returns a new value compared to the currentValue
             // this could happen because of a JsonConverter against the type
             if ((!useExistingValue || value != currentValue)
-                && ShouldSetPropertyValue(property, value))
+                && ShouldSetPropertyValue(property, containerContract as JsonObjectContract, value))
             {
                 property.ValueProvider.SetValue(target, value);
 
@@ -1076,7 +1076,7 @@ namespace Newtonsoft.Json.Serialization
             }
 
             // test tokenType here because null might not be convertible to some types, e.g. ignoring null when applied to DateTime
-            if (property.NullValueHandling.GetValueOrDefault(Serializer._nullValueHandling) == NullValueHandling.Ignore && tokenType == JsonToken.Null)
+            if (tokenType == JsonToken.Null && ResolvedNullValueHandling(containerContract as JsonObjectContract, property) == NullValueHandling.Ignore)
             {
                 return true;
             }
@@ -1129,9 +1129,9 @@ namespace Newtonsoft.Json.Serialization
             return ((value & flag) == flag);
         }
 
-        private bool ShouldSetPropertyValue(JsonProperty property, object value)
+        private bool ShouldSetPropertyValue(JsonProperty property, JsonObjectContract contract, object value)
         {
-            if (property.NullValueHandling.GetValueOrDefault(Serializer._nullValueHandling) == NullValueHandling.Ignore && value == null)
+            if (value == null && ResolvedNullValueHandling(contract, property) == NullValueHandling.Ignore)
             {
                 return false;
             }
@@ -1992,7 +1992,7 @@ namespace Newtonsoft.Json.Serialization
                 JsonProperty property = context.Property;
                 object value = context.Value;
 
-                if (ShouldSetPropertyValue(property, value))
+                if (ShouldSetPropertyValue(property, contract, value))
                 {
                     property.ValueProvider.SetValue(createdObject, value);
                     context.Used = true;

Src/Newtonsoft.Json/Serialization/JsonSerializerInternalWriter.cs

@@ -270,10 +270,9 @@ namespace Newtonsoft.Json.Serialization
             return Serializer.GetReferenceResolver().IsReferenced(this, value);
         }
 
-        private bool ShouldWriteProperty(object memberValue, JsonProperty property)
+        private bool ShouldWriteProperty(object memberValue, JsonObjectContract containerContract, JsonProperty property)
         {
-            if (property.NullValueHandling.GetValueOrDefault(Serializer._nullValueHandling) == NullValueHandling.Ignore &&
-                memberValue == null)
+            if (memberValue == null && ResolvedNullValueHandling(containerContract, property) == NullValueHandling.Ignore)
             {
                 return false;
             }
@@ -525,7 +524,7 @@ namespace Newtonsoft.Json.Serialization
                 memberValue = property.ValueProvider.GetValue(value);
                 memberContract = (property.PropertyContract.IsSealed) ? property.PropertyContract : GetContractSafe(memberValue);
 
-                if (ShouldWriteProperty(memberValue, property))
+                if (ShouldWriteProperty(memberValue, contract as JsonObjectContract, property))
                 {
                     if (ShouldWriteReference(memberValue, property, memberContract, contract, member))
                     {