How to create XElement representing date in DateTime as type xs:Date

Question

I'm using XDocument to create an XML file, as follows:

var d = DateTime.Now;

var xDocument = new XDocument(new XElement("ThisIsADate", d));

However, the resulting XML represents the date d using the xs:datetime format (e.g. "2012-05-11T00:00:00"). That is, it includes time information.

However, my XML is meant to match my XML Schema, which defines the element as being of type "xs:date". Consequently, the file is rejected when validated against the schema, because of the extra time information.

How can I fix this? I know I could just format the date myself using ToString() with a format, but this can't be the "right" way to do it, surely. I can't be expected to know how to format a date as a valid XML date - that's the job of the XML-related parts of the framework.

---

Edit: please note that I do know how to format a date using ToString(), and I also know what format string would give me the right result. That's not the answer I'm looking for. I'm looking for a function/method/class that understands what an xs:date (etc.) is, and that supports those kinds of encodings.

To be clear, I'm not looking to "get it done", I'm looking to "do it right". And re-inventing the XML wheel is not "doing it right" in my book.

Answer 1

I fixed this problem using the following class for DateElements

private class XDateElement : XElement
{
   public XDateElement(XName name, DateTime Date) : 
     base(name, Date.ToString("yyyy-MM-dd", CultureInfo.InvariantCulture))
   { }
}

The advantage of using a class like this is, that you have the specific date conversion only in one place.

var d = DateTime.Now;
var xDocument = new XDocument(new XDateElement("ThisIsADate", d));

Answer 2

As it already has been pointed out LINQ to XML is unable to produce a DateTime value using the the xs:date format. A DateTime round-trips in LINQ to XML using the xs:dateTime format and .NET does not a have a date-only type so it is not a suprise that the designers of LINQ to XML decided to only use xs:dateTime to not complicate the API.

The only option is to format the date as a string giving you full control of the format. To correctly use the xs:date format you need to convert the DateTime to a string using this code:

d.ToString("yyyy-MM-dd", CultureInfo.InvariantCulture)

Using ToShortDateString and/or not specifying a CultureInfo will not produce the desired result.