Dynamic number of textboxes(inputs) MVC

Question

In my form(razorview) i would like the user to input a number of how many attending people they would bring.

After typing the number, i would like to show as many textboxes as the number would be.

How can i achive this? At first i figured i could generate all the textboxes, but hide them with css at first. At the number input i could show the count with javascript. However, this might be a problem if i settle on 20 inputs, and they want to bring more.

Doubt anyone need code to tell me how i should start, but ill throw it in here.

Here is my current view:

@model SolutionName.Website.Presentation.Web.Models.KonferanseModel

<link href="~/Content/ContactForm.css" rel="stylesheet" />

<h3>Påmeldingsskjema</h3>
@using (Html.BeginForm("Konferansepamelding", "Page", FormMethod.Post))
{
    @Html.HiddenFor(m => m.KonferanseNavn)
    <div class="form-horizontal">
        <div class="control-group">
            <div class="controls">
                @Html.TextBoxFor(m => m.KontaktNavn, new { placeholder = "Kontaktperson" })<br />
            </div>
        </div>
        <div class="control-group">
            <div class="controls">
                @Html.TextBoxFor(m => m.FirmaNavn, new { placeholder = "Firmanavn" })<br />

            </div>
        </div>
        <div class="control-group">
            <div class="controls">
                @Html.TextBoxFor(m => m.FirmaAdresse, new { placeholder = "Firmaadresse" })<br />
            </div>
        </div>
        <div class="control-group">
            <div class="controls">
                @Html.TextBoxFor(m => m.FirmaTelefon, new { placeholder = "Firmatelefon" })<br />

            </div>
        </div>
        <div class="control-group">
            <div class="controls">
                @Html.TextBoxFor(m => m.KontaktEpost, new { placeholder = "Epostadresse" })<br />
            </div>
        </div>
        <div class="control-group">
            <div class="controls">
                @Html.TextBoxFor(m => m.NumberOfPeople, new { placeholder = "Antall deltakere" })<br />
            </div>
        </div>
        <div class="control-group">
            <div class="controls">
                @Html.TextBoxFor(m => m.FakturaInformasjon, new { placeholder = "Fakturaadresse" })<br />
            </div>
        </div>
        <div class="control-group">
            <div class="controls">
                @Html.TextAreaFor(m => m.Names, new { placeholder = "Navn på deltakere" })<br />
            </div>
        </div>
    </div>
    <input class="btn" type="submit" value="Send" /><br />
    <br />
    @Html.ValidationSummary(false)
}

model:

public class KonferanseModel
    {
        [Required(ErrorMessage = "Navn er påkrevd")]
        [Display(Name = "Fullt navn")]
        public string KontaktNavn { get; set; }

        [Required(ErrorMessage = "Gateadresse er påkrevd")]
        [Display(Name = "Gateadresse for bedriften")]
        public string FirmaAdresse { get; set; }

        [Phone(ErrorMessage = "Du må fylle inn et gyldig telefonnummer")]
        [Required(ErrorMessage = "Telefonnummer for bedriften er påkrevd")]
        [Display(Name = "Telefonnummer for bedriften")]
        public string FirmaTelefon { get; set; }

        [EmailAddress(ErrorMessage = "Du må fylle inn en gyldig epostadresse")]
        [Required(ErrorMessage = "Epost for bedriften er påkrevd")]
        [Display(Name = "Epost for bedriften")]
        public string KontaktEpost { get; set; }  

        [Required(ErrorMessage = "Fakturainformasjon er påkrevd.")]
        [Display(Name = "Fakturainformasjon")]
        public string FakturaInformasjon { get; set; }

        [Required(ErrorMessage = "Fyll inn navn på deltakere")]
        [Display(Name = "Navn på deltakere")]
        public string Names { get; set; }

        [Display(Name = "Firmanavn")]
        public string FirmaNavn { get; set; }

        [Required(ErrorMessage = "Fyll inn antall deltakere")]
        [Display(Name = "Antall deltakere")]
        [RegularExpression(@"[0-9]*$", ErrorMessage = "Antall deltakere må være et tall")]
        public string NumberOfPeople { get; set; }

        public string KonferanseNavn { get; set; }

    }

Answer 1

Here's an article about accepting a variable number of elements. http://blog.stevensanderson.com/2010/01/28/editing-a-variable-length-list-aspnet-mvc-2-style/

The gist of it is, your controller would accept a collection of your model instead of a single instance, then provide a way of generating more controls to the user.