When I update a record in mvc then give error non-nullable?

Question

I m working the crudoperation mvc with api but when I click edit record then give an error: 

The parameters dictionary contains a null entry for parameter 'PartyMstId' of non-nullable type 'System.Int32' for method 'System.Web.Mvc.ActionResult EditPatymaster(Int32)' in 'WebParty.Controllers.PartyMstsController'. An optional parameter must be a reference type, a nullable type, or be declared as an optional parameter.
Parameter name: parameters

 PartyMstsController(MVC PROJECT)

namespace WebParty.Controllers{   public class PartyMstsController : Controller
   {
  POLISHSTOCK_SJDMSEntities poly = new POLISHSTOCK_SJDMSEntities();
  public ActionResult EditPatymaster(int PartyMstId)
  {
      var std = poly.PartyMsts.Find(PartyMstId);
      return View(std);
  }

  [HttpPost]
  public JsonResult EditPatymaster(PartyMst partymst, int PartyMstId)
  {
      var partymstupdate = poly.PartyMsts.Find(PartyMstId);

      partymstupdate.PartyCode = partymst.PartyCode;
      partymstupdate.PartyName = partymst.PartyName;
      partymstupdate.Address = partymst.Address;
      partymstupdate.PhNo1 = partymst.PhNo1;
      partymstupdate.PhNo2 = partymst.PhNo2;
      partymstupdate.LogID = partymst.LogID;
      partymstupdate.PCID = partymst.PCID;
      partymstupdate.Ever = partymst.Ever;
      partymstupdate.SDate = partymst.SDate;
      partymstupdate.CompanyCode = partymst.CompanyCode;
      partymstupdate.PartyGroupCode = partymst.PartyGroupCode;
      partymstupdate.FixCode = partymst.FixCode;
      partymstupdate.OpBal = partymst.OpBal;
      partymstupdate.DivisionCode = partymst.DivisionCode;
      partymstupdate.PartyDate = partymst.PartyDate;
      partymstupdate.RDType = partymst.RDType;
      partymstupdate.Exchange = partymst.Exchange;
      partymstupdate.OpBalDollar = partymst.OpBalDollar;

      HttpResponseMessage response = staticvariable.client.PutAsJsonAsync("PartyMsts", partymst).Result;
      //entities.SaveChanges();
      return Json("your record update", JsonRequestBehavior.AllowGet);
  }
 }
}

 

  PartyMstsController(api project)

 

namespace PartyCrops.Controllers
{
    public class PartyMstsController : ApiController
    {
        private POLISHSTOCK_SJDMSEntities db = new POLISHSTOCK_SJDMSEntities();

       // PUT: api/PartyMsts/5
        [ResponseType(typeof(void))]
        public IHttpActionResult PutPartyMst(int id, PartyMst partyMst)
        {
            if (!ModelState.IsValid)
            {
                return BadRequest(ModelState);
            }

            if (id != partyMst.PartyMstId)
            {
                return BadRequest();
            }

            db.Entry(partyMst).State = EntityState.Modified;

            try
            {
                db.SaveChanges();
            }
            catch (DbUpdateConcurrencyException)
            {
                if (!PartyMstExists(id))
                {
                    return NotFound();
                }
                else
                {
                    throw;
                }
            }
            return StatusCode(HttpStatusCode.NoContent);
        }
 }
}

 

 Index.cshtml

 @Html.ActionLink("Edit", "EditPatymaster", new { id=item.PartyMstId }) |

editpartymaster.cshtml

 

@model WebParty.Models.partymstmodel   //here which model class include can u tell me(partymstmodel or partymst.cs (webapiproject->model->model1.edmx-> partymst.cs) ??????????????

@{
    ViewBag.Title = "EditPatymaster";
}

<h2>EditPatymaster</h2>

partymstmodel.cs

 

namespace WebParty.Models
{
    public class partymstmodel
    {
        public int PartyMstId { get; set; }
        public Nullable<int> PartyCode { get; set; }
        public string PartyName { get; set; }
        public string Address { get; set; }
        public string PhNo1 { get; set; }
        public string PhNo2 { get; set; }
        public Nullable<int> LogID { get; set; }
        public string PCID { get; set; }
        public Nullable<int> Ever { get; set; }
        public Nullable<System.DateTime> SDate { get; set; }
        public Nullable<int> CompanyCode { get; set; }
        public string PartyGroupCode { get; set; }
        public Nullable<int> FixCode { get; set; }
        public Nullable<decimal> OpBal { get; set; }
        public Nullable<int> DivisionCode { get; set; }
        public Nullable<System.DateTime> PartyDate { get; set; }
        public string RDType { get; set; }
        public Nullable<decimal> Exchange { get; set; }
        public Nullable<decimal> OpBalDollar { get; set; }
    }
}

 partymst.cs (webapiproject->model->model1.edmx-> partymst.cs)

 

//------------------------------------------------------------------------------
// <auto-generated>
//     This code was generated from a template.
//
//     Manual changes to this file may cause unexpected behavior in your application.
//     Manual changes to this file will be overwritten if the code is regenerated.
// </auto-generated>
//------------------------------------------------------------------------------

namespace PartyCrops.Models
{
    using System;
    using System.Collections.Generic;

    public partial class PartyMst
    {
        public int PartyMstId { get; set; }
        public Nullable<int> PartyCode { get; set; }
        public string PartyName { get; set; }
        public string Address { get; set; }
        public string PhNo1 { get; set; }
        public string PhNo2 { get; set; }
        public Nullable<int> LogID { get; set; }
        public string PCID { get; set; }
        public Nullable<int> Ever { get; set; }
        public Nullable<System.DateTime> SDate { get; set; }
        public Nullable<int> CompanyCode { get; set; }
        public string PartyGroupCode { get; set; }
        public Nullable<int> FixCode { get; set; }
        public Nullable<decimal> OpBal { get; set; }
        public Nullable<int> DivisionCode { get; set; }
        public Nullable<System.DateTime> PartyDate { get; set; }
        public string RDType { get; set; }
        public Nullable<decimal> Exchange { get; set; }
        public Nullable<decimal> OpBalDollar { get; set; }
    }
}

 plz help how to solve this problem?