Deserialize json into C# object for class which has default private constructor

Question

I need to deserialize json for following class.

public class Test {     public string Property { get; set; }      private Test()     {         //NOTHING TO INITIALIZE     }      public Test(string prop)     {         Property = prop;     } } 

I can create an instance of Test like

var instance = new Test("Instance"); 

considering my json something like

"{  "Property":"Instance" }" 

How shall I create an object of Test class as my default constructor is private and I am getting object where Property is NULL

I am using Newtonsoft Json parser.

Answer 1

You can make Json.Net call the private constructor by marking it with a [JsonConstructor] attribute:

[JsonConstructor] private Test() {     //NOTHING TO INITIALIZE } 

Note that the serializer will still use the public setters to populate the object after calling the constructor.

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Another possible option is to use the ConstructorHandling setting:

JsonSerializerSettings settings = new JsonSerializerSettings {     ConstructorHandling = ConstructorHandling.AllowNonPublicDefaultConstructor };  Test t = JsonConvert.DeserializeObject<Test>(json, settings); 

Answer 2

It doesn't seem like you need to take any extra steps.

Using Json.NET v6.0.8, the following C# program works inside LINQPad:

void Main() {        var o = JsonConvert.DeserializeObject<Test>("{\"Property\":\"Instance\"}");      Debug.Assert(o.Property == "Instance",         "Property value not set when deserializing."); }  public class Test {     public string Property { get; set; }      private Test()     {     }      public Test(string propertyValue)     {         Property = propertyValue;     } }