ASP.NET WebAPI XmlFormatter Missing UTC Offset for Dates

Question

I have an ASP.NET WebAPI implementation that I am allowing clients to consume and request either XML or JSON formatting of the HTTP response. Some of the response objects include date/time values. I have been successful in getting the JSON response to include a proper ISO 8601 formatted date (including UTC time offset) by using code like:

Dim json As JsonMediaTypeFormatter = _
  GlobalConfiguration.Configuration.Formatters.JsonFormatter
json.SerializerSettings.DateFormatHandling = _
  Newtonsoft.Json.DateFormatHandling.IsoDateFormat
json.SerializerSettings.DateTimeZoneHandling = _
  Newtonsoft.Json.DateTimeZoneHandling.Local

The JsonFormatter now gives me a date like this:

2008-11-03T14:14:00-05:00

However, the XmlFormatter gives me a date like:

2008-11-03T14:14:00

Notice the missing UTC time offset ("-05:00"). How do I get the XMLFormatter to give me the UTC time offset?

Answer 1

I believe I just figured this out myself.

When reading the dates from the SQL Server database (using an IDataReader) and the Enterprise Library Data Block, I need to use the Date.SpecifyKind method to tell what kind of date is being retrieved from the database.

Dim dateCreated As Date = _
  Date.SpecifyKind(CDate(dbReader("DateCreated")), DateTimeKind.Local)

By doing this, I was also able to remove the JsonMediaTypeFormatter lines specified in my original question. So, now both XML and JSON send the date as:

2008-11-03T14:14:00-05:00

More information on Date.SpecifyKind can be found here: http://msdn.microsoft.com/en-us/library/bb546101.aspx