Deserialize Json into class object in C#

Question

I am trying to convert json to C# object.

My test code:

public class testvm
{
   public List<testclass> results { get; set; }    
}    

public class testclass
{
   public string item1 { get; set; }

   [JsonProperty("string")]
   public string item2 { get; set; }
}    

static void jsonfun()
{    
   try
   {
      string json1 = @"{
      ""results"": [{
      ""item1"": ""testitem"" ,
      ""item2"": {
      ""string"": ""testitem2""
      }
      }]
      }";

      var obj1 = JsonConvert.DeserializeObject<testvm>(json1);
      }
      catch (Exception ex)
      { }
}

And output of above code as below Output

AS we can see item2 is becoming null because json has one extra string tag. Any suggestion how to map item2?

Answer 1

The testclass does not match the JSON object's format.

Your JSON looks like:

{
    "results": [
        {
            "item1": "testitem" ,
            "item2": {
                "string": "testitem2"
            }
        }
    ]
}

So you models should look like:

public class TestClass
{
    public string item1 { get; set; }
    public TestClass2 item2 { get; set; }
}

public class TestClass2
{
    [JsonProperty("string")]
    public string someValue { get; set; }

}

And if you want to map it a specific client model

public class ClientModel {
    public string item1 {get;set;}
    public string item2 {get;set;}

}


// After deserialization do the map
var apiModel = JsonConvert.Deserialize([...])

var clientModel = new ClientModel {
  item1 = apiModel.item1,
  item2 = apiModel.item2.someValue
}

Answer 2

Update testclass to this: item2 is some how structure like a Dictionary.

public class testclass
{
    public string item1 { get; set; }

    [JsonProperty("item2")]
    public Dictionary<string, string> item2 { get; set; }
}

Answer 3

Firstly - I recommend you to use System.Text.Json instead of Newtonsoft.Json.

In .NET Core 3.0 and .NET 5 it works faster.

Then - you shouldn't use [JsonProperty()].

How to use System.Text.Json:

public class testvm
{
   public List<testclass> results { get; set; }
}

public class testclass
{
   public string item1 { get; set; }

   public string item2 { get; set; }
}

static void Main(string[] args)
{
   testvm objBeforeSerialization = new testvm() { results = new List<testclass>() { new testclass() { item1 = "myItem1", item2 = "myItem2" } } };
            
   string myJson = JsonSerializer.Serialize(objBeforeSerialization);
                        
   testvm objAfterSerialization = JsonSerializer.Deserialize<testvm>(myJson);
}

JSON in string format will be like:

string stringObject = @"{""results"":[{""item1"":""myItem1"",""item2"":""myItem2""}]}";

You can read more about System.Text.Json in official Microsoft documentation .