I want to implement begincollectionitem step by step

See more:

C#

ASP.NET

nesting

I´m new in asp.net, and I'm using EF, and I want to implement BeginCollectionItem into my application, so in my model I have DomainEmails,DomainPasswords and DomainUsers can be added dynamically when I creating a new WebPage using somthing like "Add new" and ask me for another DomainEmails,DomainPasswords and DomainUsers

There is my model:

 public class WebPages
    {
        [Key]
        public int WebPagesId { get; set; }
        public int ClientsId { get; set; }
        [ForeignKey("ClientsId")]
        public virtual Clients Clients { get; set;}
        public String ClientsName { get; set; }
        public String DomainName { get; set; }
        public String DomainEmails { get; set; }
        public String DomainUsers { get; set; }
        public String DomainPasswords { get; set; }
          
    }
}

Viewmodel:

public class WebPagesViewModel
   {
       public String DomainName { get; set; }
       public String DomainEmails { get; set; }
       public String DomainUsers { get; set; }
       public String DomainPasswords { get; set; }
       public int SelectedClient { get; set; }
       public IEnumerable<SelectListItem> Clients { get; set; }
   }

Get Controller:

public ActionResult Create(WebPages model)
       {

           var vm = new WebPagesViewModel
           {
              
               Clients = new SelectList(db.ClientsList, "ClientsId", "ClientsName"),

           };


           return View(vm);
       }

Post Controller:

[HttpPost]
        [ValidateAntiForgeryToken]
        
        public async Task<ActionResult> Create([Bind(Include = "DomainName,DomainEmails,DomainUsers,DomainPasswords,ClientsName,SelectedClient")] WebPagesViewModel model)
        {
         

            model.Clients = new SelectList(db.ClientsList, "ClientsId", "ClientsName");
            try
            {
                if (ModelState.IsValid)
                {
                    model.WebPagesCreate();
                   
                    return RedirectToAction("Index", "WebPages");
                }

            }
            catch (Exception)
            {
              //Exception code
            }

            return View(model);
        }

Thankyou in advance!

What I have tried:

I search how to do that but examples are to different than I want to do, If any one can help me I really appreciate it!