How to add data annotations to partial class?

Question

I have an auto generated class with a property on it. I want to add some data annotations to that property in another partial class of the same type. How would I do that?

namespace MyApp.BusinessObjects
{
    [DataContract(IsReference = true)]
    public partial class SomeClass: IObjectWithChangeTracker, INotifyPropertyChanged
    {
            [DataMember]
            public string Name
            {
                get { return _name; }
                set
                {
                    if (_name != value)
                    {
                        _name = value;
                        OnPropertyChanged("Name");
                    }
                }
            }
            private string _name;
    }
}

and in another file I have:

namespace MyApp.BusinessObjects
{
    public partial class SomeClass
    {
        private SomeClass()
        {
        }

        [Required]
        public string Name{ get; set; }
    }
}

Currently, I get an error stating that the name property already exists.

Answer 1

Looks like I figured out a different way similar to the link above using MetadataTypeAttribute:

namespace MyApp.BusinessObjects
{
    [MetadataTypeAttribute(typeof(SomeClass.Metadata))]{
    public partial class SomeClass
    {
        internal sealed class Metadata
        {
            private Metadata()
            {
            }

            [Required]
            public string Name{ get; set; }
        }
    }
}