Orcas introduced a new DateTimeOffset class that is easier to use for representing absolute times than the original DateTime class. However, if you run svcutil on a contract that contains a DateTimeOffset, you'll get an ugly generated structure because DateTimeOffset isn’t recognized as a natively supported type by the system. A new class is generated by svcutil to match the schema for DateTimeOffset in the metadata.

namespace System
{
    using System.Runtime.Serialization;
    
    [DebuggerStepThroughAttribute()]
    [GeneratedCodeAttribute("System.Runtime.Serialization", "3.0.0.0")]
    [DataContractAttribute(Name="DateTimeOffset", Namespace="http://schemas.datacontract.org/2004/07/System")]
    public partial struct DateTimeOffset : IExtensibleDataObject
    {
        
        private ExtensionDataObject extensionDataField;
        
        private DateTime DateTimeField;
        
        private short OffsetMinutesField;
        
        public ExtensionDataObject ExtensionData
        {
            get
            {
                return this.extensionDataField;
            }
            set
            {
                this.extensionDataField = value;
            }
        }
        
        [DataMemberAttribute(IsRequired=true)]
        public DateTime DateTime
        {
            get
            {
                return this.DateTimeField;
            }
            set
            {
                this.DateTimeField = value;
            }
        }
        
        [DataMemberAttribute(IsRequired=true)]
        public short OffsetMinutes
        {
            get
            {
                return this.OffsetMinutesField;
            }
            set
            {
                this.OffsetMinutesField = value;
            }
        }
    }
}

There's a new option on svcutil, /targetClientVersion:Version35, that can be used to indicate that code generation should use new features in Orcas.

As far as I know, there are three places where this option makes a difference.

1. DateTimeOffset is automatically added as a known type when referenced
2. Asynchronous methods are generated using the Orcas event-based asynchronous model
3. Additional LINQ types are supported during schema import for XmlSerializer

Next time: Read Only Data Members