Dynamic texboxes form in ASP.NET MVC

Based on the article by Steve Sanderson, I was able to find the elegant solution I was looking for:

First of all, the model should be modified as follows:

public class SimpleModel
{
    public IEnumerable<EmailAddress> EmailAddresses { get; set; }
}

public class EmailAddress
{
    [Required(ErrorMessage = "Email Address is required.")]
    [DataType(DataType.EmailAddress)]
    [DisplayName("Email Address")]
    public string Value { get; set; }        
}

The controller method that processes the GET method must preinstall the model with as many entries as required:

[HandleError]
public class SimpleController : Controller
{
    public ActionResult Simple()
    {
        SimpleModel model = new SimpleModel
            {
                EmailAddresses =
                    new List<EmailAddress>
                        { 
                            // as many as required
                            new EmailAddress { Value = string.Empty }, 
                            new EmailAddress { Value = string.Empty },
                            new EmailAddress { Value = string.Empty }
                        }
            };
        return View(model);
    }

    [HttpPost]
    public ActionResult Simple(SimpleModel model)
    {
        if (ModelState.IsValid)
        {
            // handling code here
        }

        return View(model);
    }
}

The view also needs to be changed:

    <% using (Html.BeginForm()) { %>
    <%= Html.ValidationSummary(true, "The form submitted is not valid.") %>
    <div> 
        <fieldset>
            <% foreach (var item in Model.EmailAddresses)
                   Html.RenderPartial("SimpleRows", item);
             %>

            <div class="editor-field">
                <input type="submit" value="Submit" />
            </div>

        </fieldset>
    </div>
<% } %>

... . , .

<% using(Html.BeginCollectionItem("EmailAddresses")) { %>
<div class="editor-label">
    <%= Html.LabelFor(x => x.Value)%>
</div>
<div class="editor-field">
    <%= Html.TextBoxFor(x => x.Value)%>
    <%= Html.ValidationMessageFor(x => x.Value)%>
</div>
<% }%>

BeginCollectionItem - , Sanderson:

    public static class HtmlPrefixScopeExtensions
{
    private const string idsToReuseKey = "__htmlPrefixScopeExtensions_IdsToReuse_";

    public static IDisposable BeginCollectionItem(this HtmlHelper html, string collectionName)
    {
        var idsToReuse = GetIdsToReuse(html.ViewContext.HttpContext, collectionName);
        string itemIndex = idsToReuse.Count > 0 ? idsToReuse.Dequeue() : Guid.NewGuid().ToString();

        // autocomplete="off" is needed to work around a very annoying Chrome behaviour whereby it reuses old values after the user clicks "Back", which causes the xyz.index and xyz[...] values to get out of sync.
        html.ViewContext.Writer.WriteLine(string.Format("<input type=\"hidden\" name=\"{0}.index\" autocomplete=\"off\" value=\"{1}\" />", collectionName, html.Encode(itemIndex)));

        return BeginHtmlFieldPrefixScope(html, string.Format("{0}[{1}]", collectionName, itemIndex));
    }

    public static IDisposable BeginHtmlFieldPrefixScope(this HtmlHelper html, string htmlFieldPrefix)
    {
        return new HtmlFieldPrefixScope(html.ViewData.TemplateInfo, htmlFieldPrefix);
    }

    private static Queue<string> GetIdsToReuse(HttpContextBase httpContext, string collectionName)
    {
        // We need to use the same sequence of IDs following a server-side validation failure,  
        // otherwise the framework won't render the validation error messages next to each item.
        string key = idsToReuseKey + collectionName;
        var queue = (Queue<string>)httpContext.Items[key];
        if (queue == null) {
            httpContext.Items[key] = queue = new Queue<string>();
            var previouslyUsedIds = httpContext.Request[collectionName + ".index"];
            if (!string.IsNullOrEmpty(previouslyUsedIds))
                foreach (string previouslyUsedId in previouslyUsedIds.Split(','))
                    queue.Enqueue(previouslyUsedId);
        }
        return queue;
    }

    private class HtmlFieldPrefixScope : IDisposable
    {
        private readonly TemplateInfo templateInfo;
        private readonly string previousHtmlFieldPrefix;

        public HtmlFieldPrefixScope(TemplateInfo templateInfo, string htmlFieldPrefix)
        {
            this.templateInfo = templateInfo;

            previousHtmlFieldPrefix = templateInfo.HtmlFieldPrefix;
            templateInfo.HtmlFieldPrefix = htmlFieldPrefix;
        }

        public void Dispose()
        {
            templateInfo.HtmlFieldPrefix = previousHtmlFieldPrefix;
        }
    }
}

... ... , , POST.

, , , .