ASP.NET

[WebMethod]
public string Save(BusinessException exception, BusinessException oldexception)
{
     UserContext userContext = GetCurrentUserDataContext();
     IList<string> lineExtIds = exception.LineExtIds;
     IList<string> ListExtIds = exception.ListExtId;
     string username = null;
 
     //alert message should be here

     //if yes
       {
         Presenter.Save(lineExtIds,userContext.Login,userContext.Profile);
       }
 
     //if no
       {
            return;
       }
return "succeed";
}

private AppDBContext _db = new AppDBContext();
private Entities _viewModel = new Entities();
public EntityController()
{
   _viewModel.ActiveEntities = _db.Entities.ToList();
   var platformQry = _db.Platforms.AsEnumerable();
   _viewModel.Platforms = new List<Platform>(platformQry.Distinct());
}

public class Platform
{
    public int ID { get; set; }
 
    [Required]
    public string Name { get; set; }
}

public class Entities
{
     public IEnumerable<Entity> ActiveEntities { get; set; }
 
     public IEnumerable<Platform> Platforms { get; set; }
 
     public int PlatformFilterId { get; set; }
 
}

public ActionResult Index()
{
    //Build the initial entity query to filter down
    _viewModel.ActiveEntities = _db.Entities.AsEnumerable();
 
    if (_viewModel.PlatformFilterId != 0)
    { 
        //Filter by the platform ID
        _viewModel.ActiveEntities = _viewModel.ActiveEntities.Where(e => e.Platform == _viewModel.PlatformFilterId);
    }
 
    //Ensure the query is run
    _viewModel.ActiveEntities = _viewModel.ActiveEntities.ToList();
    return View(_viewModel);
}

@model AppName.ViewModels.Entities
 
@{
    ViewBag.Title = "Entity Overview";
}
 
<h2>Index</h2>
 
<p>
    @Html.ActionLink("Create New", "Create")
 
    @using (Html.BeginForm("Index", "Entity", FormMethod.Get))
    {
 
        <p>            
            @Html.DropDownListFor(x => x.PlatformFilterId , new SelectList(Model.Platforms, "ID", "Name"), "-- Filter by Platform--")
            <input type="submit" value="Filter" />
        </p>
    }
</p>
<table>
    <tr>
        <th>
            @Html.DisplayNameFor(model => model.ActiveEntities.First().Name)
        </th>
        <th>
            @Html.DisplayNameFor(model => model.ActiveEntities.First().Name)
        </th>
        <th></th>
    </tr>
 
@foreach (var item in Model.ActiveEntities) {
    <tr>
        <td>
            @Html.DisplayFor(modelItem => item.Name)
        </td>
        <td>
            @Html.DisplayFor(modelItem => item.CreatedDate)
        </td>
        <td>
            @Html.ActionLink("Edit", "Edit", new { id=item.ID }) |
            @Html.ActionLink("Details", "Details", new { id=item.ID }) |
            @Html.ActionLink("Delete", "Delete", new { id=item.ID })
        </td>
    </tr>
}
 
</table>