无法将类型为“System.Int32”的对象强制转换为类型“System.Array”

修改Edit.cshtml上部分字段，点击保存跳转到Index.cshtml。
但现在点击保存，就跳出以下错误。

 using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using System.Linq;
using System.Web;

namespace MvcSilverTalent.Models
{
    public class RetireeModel
    {
        [Key]
        [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
        public int RetireNum { get; set; }

        [Required]
        [DisplayName("单位编号")]
        [MaxLength(3)]
        public string UnitID { get; set; }

        [Required]
        [DisplayName("员工编号")]
        [MaxLength(6)]
        public string EmployeeID { get; set; }

        [Required]
        [DisplayName("离退休类型")]
        public int RetireType { get; set; }

        [Required]
        [DisplayName("删除标记")]
        public int DeleteFlag { get; set; }


        //
        // 基本信息


        [Required]
        [DisplayName("姓名")]
        [MaxLength(20)]
        public string Name { get; set; }

        [Required]
        [DisplayName("性别")]
        public Boolean Gender { get; set; }

        [Required]
        [DisplayName("身份证号码")]
        public string IDCardNo { get; set; }

        [Required]
        [DisplayName("出生年月")]
        public DateTime Brityday { get; set; }

        [Required]
        [DisplayName("民族")]
        [MaxLength(30)]
        public string Nationality { get; set; }

        [Required]
        [DisplayName("籍贯")]
        [MaxLength(30)]
        public string NativePlace { get; set; }

        [DisplayName("党派")]
        [MaxLength(30)]
        public string Party { get; set; }

        [DisplayName("所在党支部")]
        [MaxLength(100)]
        public string PartyBranch { get; set; }

        [DisplayName("最高学历")]
        [MaxLength(20)]
        public string EducationDegree { get; set; }

        [Required]
        [DisplayName("用户组")]
        public string GroupName { get; set; }

        [Required]
        [DisplayName("是否参加爱心基金")]
        public Boolean HasLoveFund { get; set; }

        [DisplayName("享受爱心基金慰问情况")]
        public string LoveFundCase { get; set; }

        [DisplayName("慰问走访情况")]
        public string VisitCase { get; set; }


        //
        // 工作信息


        [Required]
        [DisplayName("参加工作时期")]
        public int WorkPeriod { get; set; }

        [Required]
        [DisplayName("参加工作时间")]
        public DateTime WorkTime { get; set; }

        [Required]
        [DisplayName("退休时间")]
        public DateTime RetireTime { get; set; }

        [Required]
        [DisplayName("工龄")]
        public int WorkAge { get; set; }

        [Required]
        [DisplayName("退休单位")]
        [MaxLength(100)]
        public string UnitName { get; set; }

        [DisplayName("职称代码")]
        [MaxLength(3)]
        public int TitleID { get; set; }

        [DisplayName("职称")]
        [MaxLength(30)]
        public string Title { get; set; }

        [DisplayName("职务")]
        [MaxLength(30)]
        public string Position { get; set; }

        [DisplayName("编制")]
        [MaxLength(30)]
        public string Formation { get; set; }


        //
        // 可修改信息 


        [Required]
        [MaxLength(255)]
        [DisplayName("近照")]
        public string PhotoUrl { get; set; }

        [MaxLength(255)]
        [DisplayName("特长")]
        public string Specialty { get; set; }

        [Required]
        [MaxLength(255)]
        [DisplayName("现住地址")]
        public string Address { get; set; }

        [MaxLength(30)]
        [DisplayName("家庭电话")]
        public string HomeTel { get; set; }

        [MaxLength(30)]
        [DisplayName("手机号码")]
        public string MobileNum { get; set; }

        [MaxLength(10)]
        [DisplayName("邮政编码")]
        public string ZipCode { get; set; }

        [MaxLength(40)]
        [DisplayName("邮箱")]
        public string Email { get; set; }


        public virtual ICollection<EventSignModel> EventSignModels { get; set; }
        public virtual ICollection<HealthSignMain> HealthSignMains { get; set; }
    }
}

**这是controller **

        // GET: /UserInfo/Edit.cshtml

        public ActionResult Edit(int RetireNum) 
        {
            RetireeModel RetireeModel = db.RetireeModels.Find(RetireNum);
            if (RetireeModel == null)
            {
                return HttpNotFound();
            }
            return View(RetireeModel);
        }


        //
        // POST: /UserInfo/Edit.cshtml

        [HttpPost]
        [ValidateAntiForgeryToken]
        public ActionResult Edit(RetireeModel RetireeModel)
        {
            Response.Write("<script>alert('ddddd')</script>");

            if (ModelState.IsValid)
            {
                db.Entry(RetireeModel).State = EntityState.Modified;

                db.SaveChanges();
                return RedirectToAction("Index");
            }
            Response.Write("<script>alert('xxxx')</script>");

            return View("Index");
        }