Question 109042 in Json Question posted in
Our archive of expertly curated questions and answers provides insights and solutions to common problems related to this popular data interchange format. From parsing and manipulating JSON data to integrating it with various programming languages and web services, our archive has got you covered. Start exploring today and take your JSON skills to the next level

C# json.deserialize a json with a value that is sometimes a string, sometimes a int

I receive a series of json files which are not standarized, and a specific field is always a number, but sometimes quoted and sometimes unquoted.

e.g: sometimes:

{
  "skinname": "Classic Red",
  "drivername": "",
  "country": "",
  "team": "",
  "number": "0",
  "priority": 4
}

sometimes:

{
    "skinname": "Racing 125",
    "drivername": "",
    "country": "",
    "team" : "Audi Motorsport",
    "number": 125
}

And worst case:

{
  "skinname": "",
  "drivername": "",
  "country": "",
  "team": "",
  "number": "",
  "priority": 1
}

I use System.Text.Json.JsonSerializer.Deserialize<>(), deserialized to this class:

public class JsonLiveryDetails
    {
        public string skinname { get; set; }
        public string drivername { get; set; }
        public string country { get; set; }
        public string team { get; set; }
        public string number { get; set; }
        public int? priority { get; set; }
    }

I have a class to deserialize into, but of course, sometimes I get an error whether I assign that value as string or int.

I cant’t get to handle it in the get; set; of the field, so I workarounded it by catching the error, trying to deserialize it into a class with the other type and then convert the second class into the first, or catching a final error…

I find my workaround dirty, maybe (probabliy) there is a better way to handle it.

EDIT: Following Serge comments, added more details.
EDIT2: Found another case, where number is "" and makes proposed solution to fail

Tags:

2

Answers


  1. 0

    Declare the property as int and use the JsonNumberHandling attribute on the class or individual property to allow automatic casting from string to integer.

    [JsonNumberHandling(JsonNumberHandling.AllowReadingFromString)]
public class JsonLiveryDetails
{
    public string skinname { get; set; }
    public string drivername { get; set; }
    public string country { get; set; }
    public string team { get; set; }
    public int number { get; set; }
    public int? priority { get; set; }
}

    See Serge’s answer in order to be able to also handle empty strings.

    Login or Signup to reply.
  2. 0

    you can try this converter

    JsonLiveryDetails details = JsonSerializer.Deserialize<JsonLiveryDetails>(json);

public class IntToStringConverter : System.Text.Json.Serialization.JsonConverter<string>
{
    public override string Read(ref Utf8JsonReader reader, Type type, JsonSerializerOptions options)
    {
        if (reader.TokenType == JsonTokenType.Number)
             return  reader.GetInt32().ToString();
      
        return reader.GetString();
    }
   
    public override void Write(Utf8JsonWriter writer, string value, JsonSerializerOptions options)
    {
        writer.WriteStringValue(value.ToString());
    }
}

public class JsonLiveryDetails
{
    public string skinname { get; set; }
    public string drivername { get; set; }
    public string country { get; set; }
    public string team { get; set; }
    [System.Text.Json.Serialization.JsonConverter(typeof(IntToStringConverter))]
    public string number { get; set; }
    public int? priority { get; set; }
}

    or maybe it make sense to change number property type to int

    public class StringToIntConverter : System.Text.Json.Serialization.JsonConverter<int?>
{
    public override int? Read(ref Utf8JsonReader reader, Type type, JsonSerializerOptions options)
    {
        if (reader.TokenType == JsonTokenType.String)
        {
            var str = reader.GetString();

            if (!string.IsNullOrEmpty(str)
              && int.TryParse(str, out int val)) return val;
            else return default(int?);
        }
        return reader.GetInt32();
    }

    public override void Write(Utf8JsonWriter writer, int? value, JsonSerializerOptions options)
    {
        if (value != null)
            writer.WriteNumberValue((int)value);
            else writer.WriteNullValue();
    }
}

public class JsonLiveryDetails
{
    public string skinname { get; set; }
    public string drivername { get; set; }
    public string country { get; set; }
    public string team { get; set; }
[System.Text.Json.Serialization.JsonConverter(typeof(StringToIntConverter))]
    public int? number { get; set; }
    public int? priority { get; set; }
}
    Login or Signup to reply.
Please signup or login to give your own answer.

Back To Top
Search