>Hi everybody,
>
>I have the following ViewModel:
>
>

>using System;
>using System.Collections.Generic;
>using System.Linq;
>using System.Web;
>using System.Web.Mvc;
>using CardNumbers.Objects;
>using System.ComponentModel.DataAnnotations;
>using System.ComponentModel;
>
>using DataAnnotationsExtensions;
>using System.ComponentModel.DataAnnotations.Schema;
>
>namespace CardNumbers.Models
>{
>    public class ClientViewModel
>    {
>        public Client Client { get; set; }
>
>        [Key]
>        [Editable(false)]
>        [Column("ClientId", TypeName = "int")]
>        public virtual int? ClientId
>        {
>            get
>            {
>                if (Client == null)
>                    return null;
>                else
>                    return Client.Id;
>            }
>
>            set { Client.Id = value ?? 0; }
>        }
>        [Required]
>        [DisplayName("Client No")]
>        [UIHint("Number")]
>        [Column("client_no", TypeName = "smallint")]
>        [Remote("doesClientNoExist", "Client", HttpMethod = "POST",
>            AdditionalFields = "ClientId",
>            ErrorMessage = "Client Number already exists. Please enter a different Client Number.")]
>        public virtual Int16 Number
>        {
>            get
>            {
>                if (Client == null)
>                    return 0;
>                else
>                    return Client.Number;
>            }
>
>            set { Client.Number = value; }
>        }
>
>        [Required]
>        [Column("client_name", TypeName = "varchar")]
>        [DisplayName("Client Name")]
>        [MaxLength(30, ErrorMessage = "Client Name should not be longer than 30 characters")]
>        [MinLength(3, ErrorMessage = "Client Name is too short")]
>        [Remote("doesClientNameExist", "Client", HttpMethod = "POST", AdditionalFields = "ClientId",
>            ErrorMessage = "Client Name already exists. Please enter a different Client Name.")]
>        public virtual string Name
>        {
>            get
>            {
>                if (Client == null)
>                    return "";
>                else 
>                    return Client.Name;            
>            }
>
>            set { Client.Name = value; }
>        }
>
>        public int id { get; set; }
>    }
>}

>
>In the form I enter both required fields (Name and Client No) and go to save method. But the ModelState.IsValid returns false while error count is 0. How can I figure out why it is returning false?
>
>Do you see what may be wrong with my implementation here? I am trying to expose Name and Number properties because I need them somehow for RemoteValidator and I can not make them work if I use them through Model.Clients. properties that's why I attempted to expose these two properties the way I did.
>
>I added this
>
>

>var errors = ModelState.SelectMany(x => x.Value.Errors.Select(z => z.Exception));

>
>it it returned Count = 1
>[0] null
>
>which does not help me.
>
>How can I know what is wrong with the model?

I added the following code to debug the problem:

try
            {
                if (ModelState.IsValid)
                {
                    Db.AddClient(model.Client);
                    return this.Client(collection);
                }
                else
                {
                    foreach (ModelState state in ViewData.ModelState.Values.Where(x => x.Errors.Count > 0))
                    {
                        var err = state;
                    }

                   // return new AjaxableViewResult("Edit", model);
                    return PartialView("_ClientForm", model);
                }

            }
            catch
            {
                return View("Edit",model);
            }
        }

So, I can see that at some point state.Error.Count = 1 and the Exception is "Client Name is required". However, I don't understand why this message is thrown at all as both Name property and Client.Name have correct value?

May be confusion is because I have external property the same as Client's name property?