How to display 2 fields from the same table in the drop-down list MVC C#

I'm beginner in c#, and I have problem.
I have a "Person" table, (id, first name, last name). I want to create a new person, but I only have the name in the drop-down list. I need to display the name and last name.

My controller:

// GET: Magazyn
    public ActionResult Index()
    {
        var magazyn = db.Magazyn.Include(m => m.Tools).Include(m => m.Person);
        return View(magazyn.ToList());
    }

    // GET: Magazyn/Details/5
    public ActionResult Details(int? id)
    {
        if (id == null)
        {
            return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
        }
        Magazyn magazyn = db.Magazyn.Find(id);
        if (magazyn == null)
        {
            return HttpNotFound();
        }
        return View(magazyn);
    }

    // GET: Magazyn/Create
    public ActionResult Create()
    {
      
        ViewBag.IdOsoby = new SelectList(db.Person, "Id", "Name",  "Last Name");
        return View();
    }

View:

<div class="form-group">
        @Html.LabelFor(model => model.IdPerson, "IdPerson", htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            @Html.DropDownList("IdPerson", null, htmlAttributes: new { @class = "form-control" })
            @Html.ValidationMessageFor(model => model.IdPerson, "", new { @class = "text-danger" })
        </div>
    </div>

You can do something like:

public ActionResult Create()
{
   var selectList = db.Person.Select(x => new SelectListItem { Text = $"{x.Firstname} - {x.Lastname}", Value = x.Id.ToString()});
   ViewBag.IdOsoby = new SelectList(selectList, "Value", "Text");

   return View();
}

The error happens because we're trying to format the string of first name and surname. There's a couple of ways to do this. Firstly go ahead and make another Person class, make sure to mark it partial and ensure it is in the same namespace as your Person entity. So something like:

public partial class Person
{
    public string FullName => $"{Firstname} {Lastname}";
}

As you can see I have introduced a readonly property of fullname which is a combination of First and Last name. Now you can change your code in the Create action as:

public ActionResult Create()
{
   ViewBag.IdOsoby = new SelectList(db.Person.ToList(), "Id", "FullName");

   return View();
}

I make some simple, incomprehensible mistakes. My code currently looks like this. The drop-down list still does not work.

using System;
using System.Collections.Generic;
using System.Data;
using System.Data.Entity;
using System.Linq;
using System.Net;
using System.Web;
using System.Web.Mvc;
using Legoland.Models;
namespace Legoland.Controllers
{
public class MagazynController : Controller
{
private LegolandEntities db = new LegolandEntities();
// GET: Magazyn
public ActionResult Index()
{
var magazyn = db.Magazyn.Include(m => m.xxx).Include(m => m.Person);
return View(magazyn.ToList());
}
// GET: Magazyn/Details/5
public ActionResult Details(int? id)
{
if (id == null)
{
return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
}
Magazyn magazyn = db.Magazyn.Find(id);
if (magazyn == null)
{
return HttpNotFound();
}
return View(magazyn);
}
// GET: Magazyn/Create
public ActionResult Create()
{
ViewBag.Idxxx = new SelectList(db.xxx, "Id", "xxx");
ViewBag.IdPerson = new SelectList(db.Person, "Id", "Name", "LastName");
return View();
}
// POST: Magazyn/Create
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Create([Bind(Include = "Id,IdPerson,Idxxx,yyy,zzzz")] Magazyn magazyn)
{
if (ModelState.IsValid)
{
db.Magazyn.Add(magazyn);
db.SaveChanges();
return RedirectToAction("Index");
}
ViewBag.Idxxx = new SelectList(db.xxx, "Id", "xxx", magazyn.Idxxx);
ViewBag.IdPerson = new SelectList(db.Person, "Id", "Name", "LastName", magazyn.Person);
return View(magazyn);
}
// GET: Magazyn/Edit/5
public ActionResult Edit(int? id)
{
if (id == null)
{
return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
}
Magazyn magazyn = db.Magazyn.Find(id);
if (magazyn == null)
{
return HttpNotFound();
}
ViewBag.Idxxx = new SelectList(db.xxx, "Id", "xxx", magazyn.Idxxx);
var selectList = db.Person.Select(x => new SelectListItem { Text = $"{x.Name} - {x.LastName}", Value = x.Id.ToString() });
ViewBag.IdPerson = new SelectList(selectList, "Value", "Text");
return View(magazyn);
}
// POST: Magazyn/Edit/5
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Edit([Bind(Include = "Id,IdPerson,Idxxx,yyy,zzz")] Magazyn magazyn)
{
if (ModelState.IsValid)
{
db.Entry(magazyn).State = EntityState.Modified;
db.SaveChanges();
return RedirectToAction("Index");
}
ViewBag.Idxxx = new SelectList(db.xxx, "Id", "yyy", magazyn.Idxxx);
var selectList = db.Person.Select(x => new SelectListItem { Text = $"{x.Name} - {x.LastName}", Value = x.Id.ToString() });
ViewBag.IdPerson = new SelectList(selectList, "Value", "Text");
return View(magazyn);
}
// GET: Magazyn/Delete/5
public ActionResult Delete(int? id)
{
if (id == null)
{
return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
}
Magazyn magazyn = db.Magazyn.Find(id);
if (magazyn == null)
{
return HttpNotFound();
}
return View(magazyn);
}
// POST: Magazyn/Delete/5
[HttpPost, ActionName("Delete")]
[ValidateAntiForgeryToken]
public ActionResult DeleteConfirmed(int id)
{
Magazyn magazyn = db.Magazyn.Find(id);
db.Magazyn.Remove(magazyn);
db.SaveChanges();
return RedirectToAction("Index");
}
protected override void Dispose(bool disposing)
{
if (disposing)
{
db.Dispose();
}
base.Dispose(disposing);
}
}
}

And View Create.cs:

@model Legoland.Models.Magazyn
@{
ViewBag.Title = "Create";
}
<h2>Create</h2>
@using (Html.BeginForm()) 
{
@Html.AntiForgeryToken()
<div class="form-horizontal">
<h4>Magazyn</h4>
<hr />
@Html.ValidationSummary(true, "", new { @class = "text-danger" })
<div class="form-group">
@Html.LabelFor(model => model.Person, "IdPerson", htmlAttributes: new { @class = "control-label col-md-2" })
<div class="col-md-10">
@Html.DropDownList("IdPerson", null, htmlAttributes: new { @class = "form-control" })
@Html.ValidationMessageFor(model => model.IdPerson, "", new { @class = "text-danger" })
</div>
</div>
</div>
<div class="form-group">
<div class="col-md-offset-2 col-md-10">
<input type="submit" value="Create" class="btn btn-default" />
</div>
</div>
}
<div>
@Html.ActionLink("Back to List", "Index")
</div>