JSON serialization - set default value for int type

Question

I use the exist API and can't change it.

So I have some variable - CellProviderID.

It looks like it is an int, because when I set the int value the server returns the expected response.

"CellProviderID":5,"CellProviderID2":7,"CellProviderID3":2

The problem appears when I leave this value empty and after serialization I get:

"CellProviderID":0,"CellProviderID2":0,"CellProviderID3":0

because 0 is default value for int type. And the server returns an error:

{"ErrorCode":10,"ErrorMessage":"Cell provider was specified, but cell number is blank, Pager provider was specified, but pager number is blank"}

So it looks rather like it's some enum, and 0 hasn't a value.

It works well when I change serialized json from

"CellProviderID":0,"CellProviderID2":0,"CellProviderID3":0

to

"CellProviderID":"","CellProviderID2":"","CellProviderID3":""

How should I initialize the properties to be able to setup int values and get "" when I leave this property empty?

[JsonProperty]
public int CellProviderID { get; set; }
[JsonProperty]
public int CellProviderID2 { get; set; }
[JsonProperty]
public int CellProviderID3 { get; set; }

how about trying to make your properties of type int? that way they can be null (and see how the serialization reacts to that) — Batavia
– Batavia, Commented Nov 17, 2015 at 11:51
they are integer. And default value for integer is 0 insted of null. — iPogosov
– iPogosov, Commented Nov 17, 2015 at 11:53
@iPogosov He means int?, not int with a question mark. int? is shorthand form for Nullable<int> which means the type can be null or an int. That is, change your property to : public int? CellProviderID { get; set; } — Rob
– Rob ♦, Commented Nov 17, 2015 at 11:58

Mikhail Tulubaev · Accepted Answer · 2015-11-17 12:01:04Z

3

you can change return type of your properties from int to int?, so you will get null value as default.

It will be serialized as

"CellProviderID":null,"CellProviderID2":null,"CellProviderID3":null

so you can have a deal with that.

Next, you must change your serialization to ignore null values. If you're using Json.Net, you serialization must look like:

JsonConvert.SerializeObject(movie,Formatting.Indented, new JsonSerializerSettings { NullValueHandling = NullValueHandling.Ignore })

So, your server will not receive non-initialized values

edited Nov 17, 2015 at 12:01

answered Nov 17, 2015 at 11:52

Mikhail Tulubaev

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Amit Kumar Ghosh · Accepted Answer · 2015-11-17 12:56:08Z

2

You could optionally write a Custom JsonConverter and handle the custom serialization/deserialization yourself.

internal class Inherited
{
    public int MyProperty { get; set; }
    public int MyProperty2 { get; set; }
}

internal class CustomConverter : JsonConverter
{
    public override bool CanConvert(Type objectType)
    {
        return objectType == typeof(Inherited);
    }

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        throw new NotImplementedException();
    }

    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    {
        var data = value as Inherited;
        if (data != null)
        {
            writer.WriteStartObject();
            foreach (var item in typeof(Inherited).GetProperties())
            {
                writer.WritePropertyName(item.Name);
                switch (item.PropertyType.Name)
                {
                    case "Int32":
                        {
                            writer.WriteValue(default(int) == (int)item.GetValue(data, null) ? "" : item.GetValue(data, null).ToString());
                            break;
                        }
                }
            }

            writer.WriteEnd();
        }
    }
}

JsonSerializerSettings obj = new JsonSerializerSettings();
obj.Converters.Add(new CustomConverter());
var result = JsonConvert.SerializeObject(new Inherited(0) { MyProperty = 0, MyProperty2 = 0 }, obj);

Results in - {"MyProperty":"","MyProperty2":""}

answered Nov 17, 2015 at 12:56

Amit Kumar Ghosh

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2 Comments

iPogosov Over a year ago

As I understand if I have in the Inherited class int properties, when I can set default int value(0), I will get always ""?

Amit Kumar Ghosh Over a year ago

Give it a try. I think so.

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