adding row index to gridmvc in asp.net mvc

I am trying to add rowindex auto to grid.

My code is:

columns.Add().
        Titled("row").
        SetWidth(20).
        Sortable(true).
        Filterable(true).
        RenderValueAs(i++.ToString());

columns.Add(m => m.Hotel_Name_Fa).
        Titled("name").
        SetWidth(50).
        Sortable(true).
        Filterable(true);

I want this result:

 row                name
  1                  name
  2                  name2  

define these in the view at the top

   int rowNumber = 0;
   int pageSize = 5;
   int pageNumber = Convert.ToInt32(ViewBag.PageNumber);
   if ((pageNumber) > 1)
   {
       rowNumber = (pageSize * (pageNumber-1)) + rowNumber;
   }

and then in the grid

columns.Add()
        .Titled("#")
        .SetWidth(10)
        .RenderValueAs(o =>
          {
              rowNumber++;
              return @<text> @rowNumber </text>;
          });

in your controller

        ViewBag.PageNumber = (Request.QueryString["grid-page"] == null) ? "1" : Request.QueryString["grid-page"];