.NET NewtonSoft JSON deserialize map to a different property name - json

Question

I have following JSON string which is received from an external party.
{
"team":[
{
"v1":"",
"attributes":{
"eighty_min_score":"",
"home_or_away":"home",
"score":"22",
"team_id":"500"
}
},
{
"v1":"",
"attributes":{
"eighty_min_score":"",
"home_or_away":"away",
"score":"30",
"team_id":"600"
}
}
]
}
My mapping classes:
public class Attributes
{
public string eighty_min_score { get; set; }
public string home_or_away { get; set; }
public string score { get; set; }
public string team_id { get; set; }
}
public class Team
{
public string v1 { get; set; }
public Attributes attributes { get; set; }
}
public class RootObject
{
public List<Team> team { get; set; }
}
The question is that I don't like the Attributes class name and the attributes field names in the Team class. Instead, I want it to be named TeamScore and also to remove _ from the field names and give proper names.
JsonConvert.DeserializeObject<RootObject>(jsonText);
I can rename Attributes to TeamScore, but if I change the field name (attributes in the Team class), it won't deserialize properly and gives me null. How can I overcome this?

Answer 1

Json.NET - Newtonsoft has a JsonPropertyAttribute which allows you to specify the name of a JSON property, so your code should be:
public class TeamScore
{
[JsonProperty("eighty_min_score")]
public string EightyMinScore { get; set; }
[JsonProperty("home_or_away")]
public string HomeOrAway { get; set; }
[JsonProperty("score ")]
public string Score { get; set; }
[JsonProperty("team_id")]
public string TeamId { get; set; }
}
public class Team
{
public string v1 { get; set; }
[JsonProperty("attributes")]
public TeamScore TeamScores { get; set; }
}
public class RootObject
{
public List<Team> Team { get; set; }
}
Documentation: Serialization Attributes

Answer 2

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);
}
}

Answer 3

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; }
}

Answer 4

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

Answer 5

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() });

Answer 6

Also if you want to ignore something use this
[JsonIgnore]
public int Id { get; set; }
[JsonProperty("id")]
Public string real_id { get; set; }