WebGrid: next page does not remember hidden element

Question

I am creating an application in c# with mvc 2010 Express and I have one view with a drop down list to select a code. It redirects the user to another view (Filter view) with another drop down list to select a market.

Then, depending on which code and market the user has selected, it displays a table of all the countries that exist for that code and market. (One market has many countries and there is at least one analysis (defined by a code) for each country per year).

I added a hidden element in my Filter view:

@{
    string code= ViewBag.code;
}

<script type="text/javascript">
$(function () {
    $("#Market").change(function () {
    var actionUrl = $('#TheForm1').attr('action') + '/' + $('#Market').val();
        $('#TheForm1').attr('action', actionUrl);
        $('#TheForm1').submit();
    });
});
</script>

@using (Html.BeginForm("FilterAnMark", "Inform", FormMethod.Post, new { id = "TheForm1"})){
    @Html.DropDownList("Market", (SelectList)ViewBag.mar, "Select a market")
    @Html.Hidden("code", code)
}

Inform Controller:

public ActionResult Filter(string id)
{
    ViewBag.code = id;
    var merc = from a in dre.v_AnalysisCountry
               where a.Code == id
               select a;
    var query1 = merc.Select (a => new { a.Code,a.Market}).Distinct().OrderBy(a => a.Market);
    ViewBag.mar = new SelectList(query1.AsEnumerable(), "Market", "Market");
    return View();
}

public ActionResult FilterMarket(string id, string code)
{
    var countries = new FilterManager().ObtainAnMarket(code, id);
    return View(countries);
}

And then in this next view (FilterMarket) I use a WebGrid to display the countries:

@model IEnumerable<AlianzasIntranet.Models.DB.v_AnalysisCountry>

@{
    WebGrid grid = new WebGrid(Model, defaultSort: "Market", rowsPerPage: 15);
}

@grid.GetHtml(
    fillEmptyRows: true,
    mode: WebGridPagerModes.All,
    firstText: "<< First",
    previousText: "< Previous",
    nextText: "Next >",
    lastText: "Last>>",

    columns: new[] {
        grid.Column("CountryName", style: "direc", header: "Country"),
        ... [etc]
})

The problem comes when the user tries to display another page of the table, as it displays a blank table because it doesn't remember this hidden element (the code). I think I should add it somewhere in my WegGrid but I don't know where.

I would be very grateful if you could help me. I really need to finish this. Thanks in advance!

Answer 1

Creating an intermediate ActionResult in the Controller between Filter and FilterMarket solves the problem. It will obtain the IdAnalysis and then in FilterMarket the Code and Market from that IdAnalysis:

public ActionResult Filter(string id)
{
    ViewBag.code = id;
    var merc = from a in dre.v_AnalysisCountry
               where a.Code == id
               select a;
    var query1 = merc.Select (a => new { a.Code,a.Market}).Distinct().OrderBy(a => a.Market);
    ViewBag.mar = new SelectList(query1.AsEnumerable(), "Market", "Market");
    return View();
}

public ActionResult IntermFilter(string id, string code)
{
    int idFirstAn = (from m in dre.v_AnalysisCountry
                     where m.Code == code && m.Market == id
                     select m.IdAnalysis).FirstOrDefault();
    return RedirectToAction("FilterMarket", new { id = idFirstAn });
}

public ActionResult FilterMarket(int id)
{
    var query = (from m in dre.v_AnalysisCountry
                 where m.IdAnalysis == id
                 select m).FirstOrDefault();
    var countries = new FilterManager().ObtainAnMarket(query.Code, query.Market);
    return View(countries);
}