科学记数法中的JSON.NET整数

Question

We are being supplied some JSON from another system that has decided it would be fun to present integers in scientific notation. As it stands JSON.NET throws an exception of:

Input string 9.658055e+06 is not a valid integer.

I have been able to recreate the issue using some simple code:

public class TestClass
{
    public int Value { get; set; }
}

static void Main(string[] args)
{
    var json = "{Value:9.658055e+06}";

    var xx = JsonConvert.DeserializeObject<TestClass>(json);
}

Any ideas how i can get the library to deserialize this correctly?

UPDATE: Thanks for all answers, for the record changing the type to Int64 or double would not be possible for other reasons, but the converter class has done the job

Answer 1

Two ways you can do this:

First and easiest is to change the type of your Value property to System.Int64 . This would most likely "just work".

If, however, it really needs to be an int , you could do something like this:

public class TestClass
{
    [JsonConverter(typeof(JsonScientificConverter))]
    public int Value { get; set; }
}

static void Main(string[] args)
{
    var json = "{Value:9.658055e+06}";

    var xx = JsonConvert.DeserializeObject<TestClass>(json);
}

public class JsonScientificConverter : JsonConverter
{
    public override bool CanRead { get { return true; } }
    public override bool CanConvert(Type objectType)
    {
        return true;
    }

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

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        return (int)(serializer.Deserialize<System.Int64>(reader));
    }
}

Here you're reading it as a System.Int64 , but then casting it to a regular int . So you have an int , but you have to change the class and write a custom converter, which might be overcomplicating things.

Answer 2

你需要将string反序列化为Int64等价物 -

var parsed = JsonConvert.DeserializeObject<Int64>("9.658055e+06"); //9658055

Answer 3

You can serialize the value to double , and access the int equivalent with another property that is hidden to the serialization (to keep the json the same):

public class TestClass
{
    public double Value
    {
        get { return (double)IntValue; }
        set { _IntValue = (int)value; }
    }

    private int _IntValue;
    [JsonIgnore]
    public int IntValue {
        get { return _IntValue; }
        set { _IntValue = value; }
    }

}

static void Main(string[] args)
{
    var json = "{Value:9.658055e+06}";

    var xx = JsonConvert.DeserializeObject<TestClass>(json);

    Console.WriteLine(JsonConvert.SerializeObject(xx));
    Console.WriteLine(xx.IntValue); 
    Console.ReadKey();
}

As you see, the value gets correctly parsed, and when you reserialize the object, the Json stays the same, thanks to the [JsonIgnore] attribute on the IntValue property.