How to display the last inserted ID (primary key) of a table in a html textbox that is in a relationship with a foreign key of another table in mvc

Here we go . I tested this and it returned me the model properties along with files posted . This example gives you ideea how POSt method used in MVC and how to send model propertied back to controller .

      //-- this is the controller
     public class FileUploadDemoController : Controller
    {
        //
        // GET: /FileUploadDemo/

        public ActionResult Index()
        {
            // here find the last if of the FileUploadtable 
            var ctx = new TestDbContext();
            var maxId = ctx.Fileuploads.ToList().OrderByDescending(u => u.Id).FirstOrDefault();
            var newId = maxId == null ? 1 : maxId.Id + 1;
            return View("Index", new FileUploadModel { Id= newId });
        }


        [HttpPost]
        public ActionResult PostForm(FileUploadModel model)
        {
            // here you have NewId in model.Id method ; Now ypour table b in my case is fileeuploadhistory I want to insert a new record with this model.Id 

            using (var ctx = new TestDbContext())
            {
                var curretFile = ctx.Fileuploads.FirstOrDefault(x => x.Id == model.Id);
                if (curretFile==null)
                {
                    curretFile=new FileUploadModel {   Name=model.Name , ValidFromDate= model.ValidFromDate};                        

                }
                curretFile.History = new FileUploadHistory { InsertedDate = DateTime.Now };
                ctx.Fileuploads.Add(curretFile);
                ctx.SaveChanges();

            }
            return View("Index", model);
        }
    }

-- These are MY EntityFramework entities and I am using same on Views as well

  public class FileUploadModel
    {

        public FileUploadModel()
        {

        }
        [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
        public int Id { get; set; }
        public string Name { get; set; }
        public string ValidFromDate { get; set; }

        public int HistoryId { get; set; }

        [ForeignKeyAttribute("HistoryId")]
        public virtual FileUploadHistory History { get; set; }
    }

    public class FileUploadHistory
    {
        [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
        public int Id { get; set; }
        public DateTime InsertedDate { get; set; }
    }

-- Finaly the cshml file . The import point is to use new { enctype = "multipart/form-data" } inside BeginForm . // the page from where you will post the data . Please change you model class in place of FileUploadModel I created for me .

   @model WebApplication1.Models.FileUploadModel



        @using (Html.BeginForm("PostForm", "FileUploadDemo", FormMethod.Post, new { enctype = "multipart/form-data" }))
  {

   <div class="panel">
    <div class="panel-body">

        <div class="form-group row">
            <div class="col-md-2 form-label">
                <label>ID:</label>
            </div>
            <div class="col-md-6">
                @Html.TextAreaFor(x => x.Id , new { @class = "form-control" })
            </div>

        </div>


        <div class="form-group row">
            <div class="col-md-2 form-label">
                <label>Name:</label>
            </div>
            <div class="col-md-6">
                @Html.TextAreaFor(x => x.Name, new { @class = "form-control" })
            </div>

        </div>

        <div class="form-group row">
            <div class="col-md-2 form-label">
                <label>Date</label>
            </div>
            <div class="col-md-6">
                @Html.TextAreaFor(x => x.ValidFromDate, new { @class = "form-control" })
            </div>

        </div>
        <div class="col-md-10">
            <div class="form-group row">
                <div class="col-md-2 form-label">
                    <label>Select File<i class="required-field">*</i>:</label>
                </div>
                <div class="col-md-8">
                    <input type="file" class="file-upload" style="margin: 0px;" hidden="hidden" accept=".xlsx" name="file" id="file" />
                </div>
            </div>
        </div>

        <div class="form-group row">
            <div class="col-md-3 pull-right text-right">
                <button class="btn btn-primary" id="process-submission" type="submit">
                    Submit
                </button>

            </div>
        </div>
    </div>
</div>
}