DeSerialize NaN values into JSON using System.Text.Json.Serialization

David Smith

4y3.3kVisual Basic .NET

I Need to convert NaN in Json(as it is not JSON) to Double using using System.Text.Json.Serialization;.

For example, I am having following JSON:

{ "Amount": NaN }

3 Replies

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Gajendra Jangid4y ago
To serialized/deserialized, You can use an alternative way (such as strings) Json.NET stores these as strings in the payload then automatically converts to float. To demonstrate you can check the following code:
public class ClassWithNumbers
{
    public int IntNumber { get; set; }
    public float FloatNumber { get; set; }
}

// Json Serialization Options to allow literals
var options = new JsonSerializerOptions
{
    NumberHandling = JsonNumberHandling.AllowNamedFloatingPointLiterals
};

// Json Exmple
string json = @"{""IntNumber"":1,""FloatNumber"":""NaN""}";
ClassWithNumbers obj =     System.Text.Json.JsonSerializer.Deserialize(json, options);

Output:
// obj.IntNumber: 1
// obj.FloatNumber: NaN
Manikandan M4y ago
Hi David,

Hope below details will help you to resolve your question.

var settings = new JsonSerializerSettings();
var floatConverter = new LawAbidingFloatConverter();
settings.Converters.Add(floatConverter);
var myConverter = new JsonNetSerializer(settings);

public class LawAbidingFloatConverter : JsonConverter
{
public override bool CanRead
{
get
{
return false;
}
}
public override bool CanWrite
{
get
{
return true;
}
}
public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
var val = value as double? ?? (double?)(value as float?);
if (val == null || Double.IsNaN((double)val) || Double.IsInfinity((double)val))
{
writer.WriteNull();
return;
}
writer.WriteValue((double)val);
}
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
throw new NotImplementedException();
}
public override bool CanConvert(Type objectType)
{
return objectType == typeof(double) || objectType == typeof(float);
}
}

Ref Link: https://stackoverflow.com/questions/7814247/serialize-nan-values-into-json-as-nulls-in-json-net
Muhammad Imran Ansari4y ago
The only way these can be successfully serialized/deserialized is by representing them by using an alternative format (such as strings). JSon.NET stores these as strings in the payload then automatically converts to float.
public class ClassWithNumbers
{
public int IntNumber { get; set; }
public float FloatNumber { get; set; }
}

var options = new JsonSerializerOptions
{
NumberHandling = JsonNumberHandling.AllowNamedFloatingPointLiterals
};
string json = @"{""IntNumber"":1,""FloatNumber"":""NaN""}";
ClassWithNumbers obj = System.Text.Json.JsonSerializer.Deserialize(json, options);
// obj.IntNumber: 1
// obj.FloatNumber: NaN
Pre-Requisite:
dll: System.Text.Json;
Nuget Package: System.Text.Json;