public partial class MAGAZINE
    {
        public MAGAZINE()
        {
            this.AUTHORs = new HashSet<AUTHOR>();
        }

        public long REF_ID { get; set; }
        public string NOTES { get; set; }
        public string TITLE { get; set; }

        public virtual REFERENCE REFERENCE { get; set; }
        public virtual ICollection<AUTHOR> AUTHORs { get; set; }
    }

public partial class AUTHOR
{
    public AUTHOR()
    {
         this.MAGAZINEs = new HashSet<MAGAZINE>();
    }

            public long AUTHOR_ID { get; set; }
            public string FULL_NAME { get; set; }

            public virtual ICollection<MAGAZINE> MAGAZINEs { get; set; }
        }
}

public ActionResult Edit(long id)
    {
        MAGAZINE magazine = db.MAGAZINEs.Find(id);
        return View(magazine);
    }

[HttpPost]
public ActionResult Edit(MAGAZINE magazine)
   {
       if (ModelState.IsValid)
       {
           db.Entry(magazine).State = EntityState.Modified;
           db.SaveChanges();
           return RedirectToAction("Index");
       }

       return View(magazine);
   }

public class AuthorModelBinder : IModelBinder
    {
        public object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
        {
            var values = bindingContext.ValueProvider.GetValue(bindingContext.ModelName);
            if (values != null)
            {
                // We have specified asterisk (*) as a token delimiter. So
                // the ids will be separated by *. For example "2*3*5"
                var ids = values.AttemptedValue.Split('*');

                List<int> validIds = new List<int>();
                foreach (string id in ids)
                {
                    int successInt;
                    if (int.TryParse(id, out successInt))
                    {
                        validIds.Add(successInt);
                    }
                    else
                    {
                        //Make a new author
                        AUTHOR author = new AUTHOR();
                        author.FULL_NAME = id.Replace("'", "").Trim();
                        using (RefmanEntities db = new RefmanEntities())
                        {
                            db.AUTHORs.Add(author);
                            db.SaveChanges();
                            validIds.Add((int)author.AUTHOR_ID);
                        }
                    }
                }

                 //Now that we have the selected ids we could fetch the corresponding
                 //authors from our datasource
                var authors = AuthorController.GetAllAuthors().Where(x => validIds.Contains((int)x.Key)).Select(x => new AUTHOR
                {
                    AUTHOR_ID = x.Key,
                    FULL_NAME = x.Value
                }).ToList();
                return authors;
            }
            return Enumerable.Empty<AUTHOR>();
        }
    }

public ActionResult Edit(Post post)
{
  if (ModelState.IsValid)
  {
       repo.EditPost(post);
       ...
  }
  ...
}

namespace PrideParrot.Web.Controllers.ModelBinders
{
  [ValidateInput(false)]
  public class PostBinder : IModelBinder
  {
    private IRepository repo;

    public PostBinder(IRepository repo)
    {
      this.repo = repo;
    }

    #region IModelBinder Members

    public object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
    {
      HttpRequestBase request = controllerContext.HttpContext.Request;

      // retrieving the posted values.
      string oper = request.Form.Get("oper"),
               idStr = request.Form.Get("Id"),
               heading = request.Form.Get("Heading"),
               description = request.Form.Get("Description"),
               tagsStr = request.Form.Get("Tags"),
               postTypeIdStr = request.Form.Get("PostType"),
               postedDateStr = request.Form.Get("PostedDate"),
               isPublishedStr = request.Form.Get("Published"),
               fileName = request.Form.Get("FileName"),
               serialNoStr = request.Form.Get("SerialNo"),
               metaTags = request.Form.Get("MetaTags"),
               metaDescription = request.Form.Get("MetaDescription"),
               themeIdStr = request.Form.Get("Theme");

      // initializing to default values.
      int id = 0, serialNo = 0;
      DateTime postedDate = DateTime.UtcNow;
      DateTime? modifiedDate = DateTime.UtcNow;
      postedDate.AddMilliseconds(-postedDate.Millisecond);
      modifiedDate.Value.AddMilliseconds(-modifiedDate.Value.Millisecond);

      /*if operation is not specified throw exception.
        operation should be either'add' or 'edit'*/
      if (string.IsNullOrEmpty(oper))
        throw new Exception("Operation not specified");

      // if there is no 'id' in edit operation add error to model.
      if (string.IsNullOrEmpty(idStr) || idStr.Equals("_empty"))
      {
        if (oper.Equals("edit"))
          bindingContext.ModelState.AddModelError("Id", "Id is empty");
      }
      else
        id = int.Parse(idStr);

      // check if heading is not empty.
      if (string.IsNullOrEmpty(heading))
        bindingContext.ModelState.AddModelError("Heading", "Heading: Field is required");
      else if (heading.Length > 500)
        bindingContext.ModelState.AddModelError("HeadingLength", "Heading: Length should not be greater than 500 characters");

      // check if description is not empty.
      if (string.IsNullOrEmpty(description))
        bindingContext.ModelState.AddModelError("Description", "Description: Field is required");

      // check if tags is not empty.
      if (string.IsNullOrEmpty(metaTags))
        bindingContext.ModelState.AddModelError("Tags", "Tags: Field is required");
      else if (metaTags.Length > 500)
        bindingContext.ModelState.AddModelError("TagsLength", "Tags: Length should not be greater than 500 characters");

      // check if metadescription is not empty.
      if (string.IsNullOrEmpty(metaTags))
        bindingContext.ModelState.AddModelError("MetaDescription", "Meta Description: Field is required");
      else if (metaTags.Length > 500)
        bindingContext.ModelState.AddModelError("MetaDescription", "Meta Description: Length should not be greater than 500 characters");

      // check if file name is not empty.
      if (string.IsNullOrEmpty(fileName))
        bindingContext.ModelState.AddModelError("FileName", "File Name: Field is required");
      else if (fileName.Length > 50)
        bindingContext.ModelState.AddModelError("FileNameLength", "FileName: Length should not be greater than 50 characters");

      bool isPublished = !string.IsNullOrEmpty(isPublishedStr) ? Convert.ToBoolean(isPublishedStr.ToString()) : false;

      //** TAGS
      var tags = new List<PostTag>();
      var tagIds = tagsStr.Split(',');
      foreach (var tagId in tagIds)
      {
        tags.Add(repo.PostTag(int.Parse(tagId)));
      }
      if(tags.Count == 0)
        bindingContext.ModelState.AddModelError("Tags", "Tags: The Post should have atleast one tag");

      // retrieving the post type from repository.
      int postTypeId = !string.IsNullOrEmpty(postTypeIdStr) ? int.Parse(postTypeIdStr) : 0;
      var postType = repo.PostType(postTypeId);
      if (postType == null)
        bindingContext.ModelState.AddModelError("PostType", "Post Type is null");

      Theme theme = null;
      if (!string.IsNullOrEmpty(themeIdStr))
        theme = repo.Theme(int.Parse(themeIdStr));

      // serial no
      if (oper.Equals("edit"))
      {
        if (string.IsNullOrEmpty(serialNoStr))
          bindingContext.ModelState.AddModelError("SerialNo", "Serial No is empty");
        else
          serialNo = int.Parse(serialNoStr);
      }
      else
      {
        serialNo = repo.TotalPosts(false) + 1;
      }

      // check if commented date is not empty in edit.
      if (string.IsNullOrEmpty(postedDateStr))
      {
        if (oper.Equals("edit"))
          bindingContext.ModelState.AddModelError("PostedDate", "Posted Date is empty");
      }
      else
        postedDate = Convert.ToDateTime(postedDateStr.ToString());

      // CREATE NEW POST INSTANCE
      return new Post
      {
        Id = id,
        Heading = heading,
        Description = description,
        MetaTags = metaTags,
        MetaDescription = metaDescription,
        Tags = tags,
        PostType = postType,
        PostedDate = postedDate,
        ModifiedDate = oper.Equals("edit") ? modifiedDate : null,
        Published = isPublished,
        FileName = fileName,
        SerialNo = serialNo,
        Theme = theme
      };
    }

    #endregion
  }
}