c# TimeZoneInfo serialization

Question

I'm have a bit of a problem with serializing TimeZoneInfo object. I was trying to use TimeZoneInfo variable in data contract for WCF service but the serialization was failing. So i wrote this little piece of code to test the serialization. Here's a what i do:

        var fileName = "tmp.xml";
        var tz = TimeZoneInfo.Local;
        var dataSer = new DataContractSerializer(typeof(TimeZoneInfo));

        try
        {
            using (var xml = new FileStream(fileName, FileMode.Create))
            {
                dataSer.WriteObject(xml, tz);
            }
        }
        catch (Exception e)
        {
            Console.WriteLine(e.Message);
        }

Now, when i call WriteObject method it throws an exception:

Type 'System.TimeZoneInfo+AdjustmentRule[]' with data contract name 'ArrayOfTimeZoneInfo.AdjustmentRule:http://schemas.datacontract.org/2004/07/System' is not expected. Consider using a DataContractResolver or add any types not known statically to the list of known types - for example, by using the KnownTypeAttribute attribute or by adding them to the list of known types passed to DataContractSerializer.

If i attempt to add [KnownType(typeof(System.TimeZoneInfo.AdjustmentRule[]))] to the class i get the same error. And if i add this line to my data contract interface i get compile error:

Error 1 'System.TimeZoneInfo.AdjustmentRule' is inaccessible due to its protection level

And according to the documentation TimeZoneInfo class implements ISerializable so it should serialize by default.

Can anyone tell me what i'm doing wrong here? I would appreciate any help.

Thanks.

Jon Skeet Jon Skeet · Accepted Answer · 2011-10-09T16:38:31

I'm not sure why it doesn't just serialize simply, but have you considered just serializing the ID? That's likely to be rather more efficient - and simpler! - than serializing all the information inside, and should be fine so long as both systems have that time zone.

EDIT: Note that this won't work with custom time zones, for which you should look at ToSerializedString as noted elsewhere.

c# TimeZoneInfo serialization

3 Answers