Question

37

Custom JavaScriptConverter for DateTime?

rated 0 times [ 44] [ 7] / answers: 1 / hits: 22996 / 15 Years ago, thu, august 27, 2009, 12:00:00

I have an object, it has a DateTime property... I want to pass that object from an .ashx handler back to a webpage via AJAX/JSON... I don't want to use 3rd party controls...

when I do this:

  new JavaScriptSerializer().Serialize(DateTime.Now);

I get this:

  /Date(1251385232334)/

but I want 8/26/2009 (nevermind localization... my app is very localized, so my date formatting assumptions are not up for debate in this question). If I make/register a custom converter

public class DateTimeConverter : JavaScriptConverter

{

    public override IEnumerable<Type> SupportedTypes

    {

        get { return new List<Type>() { typeof(DateTime), typeof(DateTime?) }; }

    }



    public override IDictionary<string, object> Serialize(object obj, JavaScriptSerializer serializer)

    {

        Dictionary<string, object> result = new Dictionary<string, object>();

        if (obj == null) return result;

        result[DateTime] = ((DateTime)obj).ToShortDateString();

        return result;

    }



    public override object Deserialize(IDictionary<string, object> dictionary, Type type, JavaScriptSerializer serializer)

    {

        if (dictionary.ContainsKey(DateTime))

            return new DateTime(long.Parse(dictionary[DateTime].ToString()), DateTimeKind.Unspecified);

        return null;

    }

}

then I get this result (since the return value of the custom serialize method is a dictionary):

{DateTime:8/27/2009}

so now in my Javascript, instead of doing

somePerson.Birthday

I have to do

somePerson.Birthday.DateTime 



  or



somePerson.Birthday[DateTime]

how can I make the custom converter return a direct string so that I can have clean Javascript?

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marinal

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2 Years ago

answered 15 Years ago malkajillc · Accepted Answer

JavaScriptSerializer can definitely do what you desire.

It's possible to customize the serialization performed by JavaScriptSerializer for any type by creating a custom converter and registering it with the serializer. If you have a class called Person, we could create a converter like so:

public class Person

{

    public string Name { get; set; }

    public DateTime Birthday { get; set; }

}



public class PersonConverter : JavaScriptConverter

{

    private const string _dateFormat = MM/dd/yyyy;



    public override IEnumerable<Type> SupportedTypes

    {

        get

        {

            return new[] { typeof(Person) };

        }

    }



    public override object Deserialize(IDictionary<string, object> dictionary, Type type, JavaScriptSerializer serializer)

    {

        Person p = new Person();

        foreach (string key in dictionary.Keys)

        {

            switch (key)

            {

                case Name:

                    p.Name = (string)dictionary[key];

                    break;



                case Birthday:

                    p.Birthday = DateTime.ParseExact(dictionary[key] as string, _dateFormat, DateTimeFormatInfo.InvariantInfo);

                    break;

            }

        }

        return p;

    }



    public override IDictionary<string, object> Serialize(object obj, JavaScriptSerializer serializer)

    {

        Person p = (Person)obj;

        IDictionary<string, object> serialized = new Dictionary<string, object>();

        serialized[Name] = p.Name;

        serialized[Birthday] = p.Birthday.ToString(_dateFormat);

        return serialized;

    }

}

And use it like this:

JavaScriptSerializer serializer = new JavaScriptSerializer();

serializer.RegisterConverters(new[] { new PersonConverter() });



Person p = new Person

            {

                Name = User Name,

                Birthday = DateTime.Now

            };



string json = serializer.Serialize(p);

Console.WriteLine(json);

// {Name:User Name,Birthday:12/20/2010}



Person fromJson = serializer.Deserialize<Person>(json);

Console.WriteLine(String.Format({0}, {1}, fromJson.Name, fromJson.Birthday)); 

// User Name, 12/20/2010 12:00:00 AM