Question

How do I get the JavaScriptSerializer from System.Web.Extensions to use CultureInfo.CurrentCulture?

I’m getting exceptions deserializing DD/MM/YYYY DateTimes, as it’s currently expecting them in US format, which is incorrect for our application.

Answer 1

Per the MDSN notes on JavaScriptSerializer:

Date object, represented in JSON as “/Date(number of ticks)/”. The number of ticks is a positive or negative long value that indicates the number of ticks (milliseconds) that have elapsed since midnight 01 January, 1970 UTC.

The maximum supported date value is MaxValue (12/31/9999 11:59:59 PM) and the minimum supported date value is MinValue (1/1/0001 12:00:00 AM).

You’ll need to register a JavaScriptConverter for DateTime that handles your type:

public class DateTimeConverter : JavaScriptConverter
{

    public override object Deserialize(IDictionary<string, object> dictionary, Type type, JavaScriptSerializer serializer)
    {
        if (dictionary == null)
            throw new ArgumentNullException("dictionary");

        if (type == typeof(DateTime))
        {
            DateTime time;
            time = DateTime.Parse(dictionary["Time"].ToString(), /** put your culture info here **/);

            return time;
        }

        return null;
    }

    public override IDictionary<string, object> Serialize(object obj, JavaScriptSerializer serializer)
    {
        DateTime? time = obj as DateTime?;

        if (time == null)
        {
            Dictionary<string, object> result = new Dictionary<string, object>();
            result["Time"] = time.Value;

            return result;
        }

        return new Dictionary<string, object>();
    }

    public override IEnumerable<Type> SupportedTypes
    {
        get { return new ReadOnlyCollection<Type>(new List<Type>(new Type[] { typeof(DateTime) })); }
    }
}

Bear in mind you’ll need to account for what your JSON will actually have in terms of object property names (you’re probably using a name other than “Time”).

Register it on your JavaScriptSerializer:

serializer.RegisterConverters(new List<JavaScriptConverter>() { new DateTimeConverter() });

Finally, note that there’s more that can be done, and this is only an example to build on. Explicitly, it is searching for dictionary items with the name “Time”, and isn’t handling parse failures. You might have more than just one name for fields using DateTime.