Search parameter in MVC 5

I'm trying to figure out one of package in ASP.Net MVC 5 called MVC.Grid.

I have model like below :

public class MasterCustomer
{
    public System.Guid Id { get; set; }
    public string Code { get; set; }
    public string Name { get; set; }
}

And controller like this :

public class MasterCustomersController : Controller
{
    private ApplicationDbContext db = new ApplicationDbContext();

    // GET: MasterCustomers
    public ActionResult Index()
    {
        if (HttpContext.Request.Headers["X-Requested-With"] == "XMLHttpRequest")
            return PartialView("_IndexGrid", db.MasterCustomers.ToList());

        return View(db.MasterCustomers.ToList());
    }

    [HttpGet]
    public PartialViewResult IndexGrid(String search)
    {
        return PartialView("_IndexGrid", db.MasterCustomers.Find(search));
    }
}

I want to separate this into two questions:

1. How this controller works, when I do sort or search, it returns correctly even there is no controller handle for the action. Example :

   http://localhost/MasterCustomers?search=&sort=code&order=asc&_=1533109639307 http://localhost/MasterCustomers?search=&sort=code&order=asc&code-contains=tes&code-op=&code-contains=&_=1533109639308

   even there is no sort and order or contains action in my controller, this action working nicely.

2. sadly one of GlobalSearch action search didn't work correctly. It returns all data no matter what I typed. Example : http://localhost/MasterCustomers?search=sdfasdfasdfasdfsadwrh2w3rwegaweg&_=1533109639344

If I know how question in no. 1 works maybe I can figure out the question in no.2.

1. The full source code is available for this Open Source Project, so if you have some patience, you could find out yourself. Basically, by executing Html.Grid(Model) in the View, a new HtmlGrid is constructed, which has raw access to your query parameters:

   grid.Query = new NameValueCollection(grid.ViewContext.HttpContext.Request.QueryString);
   

   so these don't have to be Route Attributes.

2. Your Ajax Check ("if (HttpContext.Request.Headers["X-...") appears to be incorrect, where did you get that from? The implementation example on the page you provided is clearly different. By calling Index instead of IndexGrid as it's supposed to be, you lose the search parameter

Change your index to :

public ActionResult Index()
{
    return View();
}

and IndexGrid to :

[HttpGet]
public PartialViewResult IndexGrid(String search)
{
    if (String.IsNullOrEmpty(search))
        return PartialView("_IndexGrid", db.MasterCustomers.ToList());
    else
        return PartialView("_IndexGrid", db.MasterCustomers.Where(x => x.Code.Contains(search) || x.Name.Contains(search)).ToList());
}