.NET NewtonSoft JSON deserialize map to a different property name

If you'd like to use dynamic mapping, and don't want to clutter up your model with attributes, this approach worked for me

Usage:

var settings = new JsonSerializerSettings(); settings.DateFormatString = "YYYY-MM-DD"; settings.ContractResolver = new CustomContractResolver(); this.DataContext = JsonConvert.DeserializeObject<CountResponse>(jsonString, settings); 

Logic:

public class CustomContractResolver : DefaultContractResolver { private Dictionary<string, string> PropertyMappings { get; set; } public CustomContractResolver() { this.PropertyMappings = new Dictionary<string, string> { {"Meta", "meta"}, {"LastUpdated", "last_updated"}, {"Disclaimer", "disclaimer"}, {"License", "license"}, {"CountResults", "results"}, {"Term", "term"}, {"Count", "count"}, }; } protected override string ResolvePropertyName(string propertyName) { string resolvedName = null; var resolved = this.PropertyMappings.TryGetValue(propertyName, out resolvedName); return (resolved) ? resolvedName : base.ResolvePropertyName(propertyName); } } 

Adding to Jacks solution. I need to Deserialize using the JsonProperty and Serialize while ignoring the JsonProperty (or vice versa). ReflectionHelper and Attribute Helper are just helper classes that get a list of properties or attributes for a property. I can include if anyone actually cares. Using the example below you can serialize the viewmodel and get "Amount" even though the JsonProperty is "RecurringPrice".

 /// <summary> /// Ignore the Json Property attribute. This is usefule when you want to serialize or deserialize differently and not /// let the JsonProperty control everything. /// </summary> /// <typeparam name="T"></typeparam> public class IgnoreJsonPropertyResolver<T> : DefaultContractResolver { private Dictionary<string, string> PropertyMappings { get; set; } public IgnoreJsonPropertyResolver() { this.PropertyMappings = new Dictionary<string, string>(); var properties = ReflectionHelper<T>.GetGetProperties(false)(); foreach (var propertyInfo in properties) { var jsonProperty = AttributeHelper.GetAttribute<JsonPropertyAttribute>(propertyInfo); if (jsonProperty != null) { PropertyMappings.Add(jsonProperty.PropertyName, propertyInfo.Name); } } } protected override string ResolvePropertyName(string propertyName) { string resolvedName = null; var resolved = this.PropertyMappings.TryGetValue(propertyName, out resolvedName); return (resolved) ? resolvedName : base.ResolvePropertyName(propertyName); } } 

Usage:

 var settings = new JsonSerializerSettings(); settings.DateFormatString = "YYYY-MM-DD"; settings.ContractResolver = new IgnoreJsonPropertyResolver<PlanViewModel>(); var model = new PlanViewModel() {Amount = 100}; var strModel = JsonConvert.SerializeObject(model,settings); 

Model:

public class PlanViewModel { /// <summary> /// The customer is charged an amount over an interval for the subscription. /// </summary> [JsonProperty(PropertyName = "RecurringPrice")] public double Amount { get; set; } /// <summary> /// Indicates the number of intervals between each billing. If interval=2, the customer would be billed every two /// months or years depending on the value for interval_unit. /// </summary> public int Interval { get; set; } = 1; /// <summary> /// Number of free trial days that can be granted when a customer is subscribed to this plan. /// </summary> public int TrialPeriod { get; set; } = 30; /// <summary> /// This indicates a one-time fee charged upfront while creating a subscription for this plan. /// </summary> [JsonProperty(PropertyName = "SetupFee")] public double SetupAmount { get; set; } = 0; /// <summary> /// String representing the type id, usually a lookup value, for the record. /// </summary> [JsonProperty(PropertyName = "TypeId")] public string Type { get; set; } /// <summary> /// Billing Frequency /// </summary> [JsonProperty(PropertyName = "BillingFrequency")] public string Period { get; set; } /// <summary> /// String representing the type id, usually a lookup value, for the record. /// </summary> [JsonProperty(PropertyName = "PlanUseType")] public string Purpose { get; set; } } 

Expanding Rentering.com's answer, in scenarios where a whole graph of many types is to be taken care of, and you're looking for a strongly typed solution, this class can help, see usage (fluent) below. It operates as either a black-list or white-list per type. A type cannot be both (Gist - also contains global ignore list).

public class PropertyFilterResolver : DefaultContractResolver { const string _Err = "A type can be either in the include list or the ignore list."; Dictionary<Type, IEnumerable<string>> _IgnorePropertiesMap = new Dictionary<Type, IEnumerable<string>>(); Dictionary<Type, IEnumerable<string>> _IncludePropertiesMap = new Dictionary<Type, IEnumerable<string>>(); public PropertyFilterResolver SetIgnoredProperties<T>(params Expression<Func<T, object>>[] propertyAccessors) { if (propertyAccessors == null) return this; if (_IncludePropertiesMap.ContainsKey(typeof(T))) throw new ArgumentException(_Err); var properties = propertyAccessors.Select(GetPropertyName); _IgnorePropertiesMap[typeof(T)] = properties.ToArray(); return this; } public PropertyFilterResolver SetIncludedProperties<T>(params Expression<Func<T, object>>[] propertyAccessors) { if (propertyAccessors == null) return this; if (_IgnorePropertiesMap.ContainsKey(typeof(T))) throw new ArgumentException(_Err); var properties = propertyAccessors.Select(GetPropertyName); _IncludePropertiesMap[typeof(T)] = properties.ToArray(); return this; } protected override IList<JsonProperty> CreateProperties(Type type, MemberSerialization memberSerialization) { var properties = base.CreateProperties(type, memberSerialization); var isIgnoreList = _IgnorePropertiesMap.TryGetValue(type, out IEnumerable<string> map); if (!isIgnoreList && !_IncludePropertiesMap.TryGetValue(type, out map)) return properties; Func<JsonProperty, bool> predicate = jp => map.Contains(jp.PropertyName) == !isIgnoreList; return properties.Where(predicate).ToArray(); } string GetPropertyName<TSource, TProperty>( Expression<Func<TSource, TProperty>> propertyLambda) { if (!(propertyLambda.Body is MemberExpression member)) throw new ArgumentException($"Expression '{propertyLambda}' refers to a method, not a property."); if (!(member.Member is PropertyInfo propInfo)) throw new ArgumentException($"Expression '{propertyLambda}' refers to a field, not a property."); var type = typeof(TSource); if (!type.GetTypeInfo().IsAssignableFrom(propInfo.DeclaringType.GetTypeInfo())) throw new ArgumentException($"Expresion '{propertyLambda}' refers to a property that is not from type '{type}'."); return propInfo.Name; } } 

Usage:

var resolver = new PropertyFilterResolver() .SetIncludedProperties<User>( u => u.Id, u => u.UnitId) .SetIgnoredProperties<Person>( r => r.Responders) .SetIncludedProperties<Blog>( b => b.Id) .Ignore(nameof(IChangeTracking.IsChanged)); //see gist 

I am using JsonProperty attributes when serializing but ignoring them when deserializing using this ContractResolver:

public class IgnoreJsonPropertyContractResolver: DefaultContractResolver { protected override IList<JsonProperty> CreateProperties(Type type, MemberSerialization memberSerialization) { var properties = base.CreateProperties(type, memberSerialization); foreach (var p in properties) { p.PropertyName = p.UnderlyingName; } return properties; } } 

The ContractResolver just sets every property back to the class property name (simplified from Shimmy's solution). Usage:

var airplane= JsonConvert.DeserializeObject<Airplane>(json, new JsonSerializerSettings { ContractResolver = new IgnoreJsonPropertyContractResolver() }); 

Also if you want to ignore something use this

 [JsonIgnore] public int Id { get; set; } [JsonProperty("id")] Public string real_id { get; set; }