ValidateDelta.cs

using System;
using System.ComponentModel.DataAnnotations;
using System.Net;
using System.Net.Http;
using System.Text;
using System.Web.Http;
using System.Web.Http.Controllers;
using System.Web.Http.OData;
using System.Web.Http.OData.Builder;

namespace ValidateDelta
{
    class Program
    {
        static void Main(string[] args)
        {
            ODataConventionModelBuilder builder = new ODataConventionModelBuilder();
            builder.EntitySet<Customer>("Customers");

            HttpServer server = new HttpServer();
            server.Configuration.Routes.MapODataRoute("odata", "", builder.GetEdmModel());

            HttpClient client = new HttpClient(server);

            var request = new HttpRequestMessage(new HttpMethod("Patch"), "http://localhost/Customers(42)");
            request.Content = new StringContent("{ }", Encoding.Default, "application/json");
            var response = client.SendAsync(request).Result;

            Console.WriteLine(response);
            if (response.Content != null)
            {
                Console.WriteLine(response.Content.ReadAsStringAsync().Result);
            }
        }
    }

    public class CustomersController : ODataController
    {
        public void Patch(Delta<Customer> delta)
        {
            Customer c = new Customer();
            delta.Patch(c);

            Validate(c, typeof(Customer));
        }

        private void Validate(object model, Type type)
        {
            var validator = Configuration.Services.GetBodyModelValidator();
            var metadataProvider = Configuration.Services.GetModelMetadataProvider();

            HttpActionContext actionContext = new HttpActionContext(ControllerContext, Request.GetActionDescriptor());

            if (!validator.Validate(model, type, metadataProvider, actionContext, String.Empty))
            {
                throw new HttpResponseException(Request.CreateErrorResponse(HttpStatusCode.BadRequest, actionContext.ModelState));
            }
        }
    }

    public class Customer
    {
        public int ID { get; set; }

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