静态与公共财产

我在MVC中编写代码，但我不理解项目中的行为公共属性！！我的代码具有非常简单的增量属性。当我点击按钮时，属性将被覆盖。只有当我有STATIC属性时它才起作用，但当我有PUBLIC时，增量就不起作用了。公共财产转瞬即逝？你能帮我理解吗，它是我的控制器：

  public class DatsController : Controller
{
    // GET: Dats
    Dats dats;
    static public int _Var
    {
        get; set;
    }
    public DatsController()
    {           
            dats = new Dats();      
    }
    public ActionResult Index()
    {
         if (Request.HttpMethod == "post")
         {
             ViewBag.zmienna = _Var;
             dats.dayToday = DateTime.Now.Date;
         }
         else
         {
            // var = var + 5;
             ViewBag.zmienna = _Var;
         }
        return View();
    }
    public ActionResult Next()
    {
        _Var = _Var + 5;
        //dats.firstDayWeek = data.firstDayWeek.AddDays(7);
        return RedirectToAction("Index", "Dats");
    }
}

好的，谢谢你的回答！！我被阅读了，我被写了另一个代码，但仍然没有工作。。。。我知道问题出在哪里，但不知道如何解决；/如果你能帮我，我会很高兴的：）

我的型号：

 public class Dats
{
     static private DateTime _dataToday;
     static private DateTime _firstDayWeek;
     static private DateTime _lastDayWeek;
     static public DateTime DayToday { get { return _dataToday = DateTime.Now.Date; } }
     static public DateTime FirstDayWeek { get { return _firstDayWeek = Dats.pierwszyDzienTygodnia(_dataToday); } set { _firstDayWeek = value; } }
     static public DateTime LastDayWeek { get { return _lastDayWeek = Dats.ostatniDzienTygodnia(_dataToday); } set { _lastDayWeek = value; } }
    static public DateTime pierwszyDzienTygodnia(DateTime data)
    {
        int dzien = DayOfWeek.Monday - data.DayOfWeek;
        if (dzien > 0)
        {
            dzien -= 7;
        }
        return data.Date.AddDays(dzien);
    }
    static public DateTime ostatniDzienTygodnia(DateTime data)
    {
        DateTime ostatniDzien = pierwszyDzienTygodnia(data.Date);
        return ostatniDzien.Date.AddDays(6);
    }
}

我的控制器：

public class DatsController : Controller
{
    public ActionResult Index()
    {
         return View();
    }
    public ActionResult Next()
    {
        Dats.FirstDayWeek = Dats.FirstDayWeek.AddDays(7);
        return RedirectToAction("Index", "Dats");
    }
}

我的观点：

@using (Html.BeginForm("Next", "Dats", FormMethod.Post))
{
    <button type="submit">Next</button>
    @*@Html.ActionLink("dalej","Next", "Visits",new {data =7})*@
    <dl class="dl-horizontal">
        @Dats.DayToday
        <dd>@Dats.FirstDayWeek</dd>
        <dd>@Dats.LastDayWeek</dd>
    </dl>
}

我想在我的房产中增加日期firstDayWeek。

class A{
  public static int c;
};
class B{
  public int c;
}
A a = new A();
a.c =0;
a.c++;//1
A aa = new A();
aa.c++;//2
B b= new B();
b.c++;//1;
B bb = new B();
bb.c++;//1