C# JSON Serialize changes String to Number type

StringToLongConverter.cs

using Newtonsoft.Json;
using Newtonsoft.Json.Linq;

public class StringToLongConverter : JsonConverter
    {
        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
        {
            JToken jt = JValue.ReadFrom(reader);

            return jt.Value<string>();
        }

        public override bool CanConvert(Type objectType)
        {
            return typeof(System.String).Equals(objectType);
        }

        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
        {
            serializer.Serialize(writer, long.Parse(value.ToString()));
        }
    }

Use it like this: (In model class)

[JsonConverter(typeof(StringToLongConverter))]
public string DateOfArrival { get => dateOfArrival; set => dateOfArrival = value; }