Ajax.beginform with captcha fails when captcha input is invalid - asp.net

Question

Im using CaptchaMvc.Mvc4 1.5.0 in a form with #Ajax.BeginForm in my Asp.net MVC4 application. when input is valid it works fine. but when captcha input is invalid. dispose method is called and i cant resubmit the message. and the captcha image dosnt change.
This is my View:
#using CaptchaMvc.HtmlHelpers;
#using CaptchaMvc;
#model Web.Models.Message
#using (Ajax.BeginForm("Contact", "Home", new AjaxOptions
{
HttpMethod = "post",
InsertionMode = InsertionMode.Replace,
UpdateTargetId = "Sent"
}))
{
#Html.AntiForgeryToken()
#Html.ValidationSummary(true)
<fieldset>
#Html.LabelFor(model => model.Message1)
#Html.TextBoxFor(model => model.Message1)
#Html.ValidationMessageFor(model => model.Message1)
#Html.MathCaptcha()
<input type="submit" value="Create" />
</fieldset>
<div id="Sent">
</div>
}
And this is my Action method:
[HttpPost]
public ActionResult Contact(Message message)
{
if(this.IsCaptchaValid("error"))
if (ModelState.IsValid )
{
db.Messages.Add(message);
db.SaveChanges();
return RedirectToAction("SuccessfullySent");
}
ModelState.AddModelError("", "there is some error");
return Content("there is some error");
}
ps: I tested it with #htmal.Beginform and it worked fine. some how problem is related to #Ajax.Beginform.

Answer 1

the trick is create a partial view and put code for generate captcha on it :
#using CaptchaMvc.HtmlHelpers
#using CaptchaMvc;
<div>
#Html.MathCaptcha()
</div>
<div>
#ViewBag.CaptchaInvalid
</div>
<div>
#ViewBag.Successfully
</div>
and in the main form where the ajax.beginform is put rendering this parcial view on the updateTargetId div "Sent":
<div id="Sent">
#{Html.RenderPartial("~/Views/Shared/CaptchaGenerate.cshtml");}
</div>
and in the action method make this changes:
[HttpPost]
public ActionResult Contact(Message message)
{
if(this.IsCaptchaValid("error"))
if (ModelState.IsValid )
{
db.Messages.Add(message);
db.SaveChanges();
ViewBag.CaptchaInvalid = "";
ViewBag.Successfully = "successfully sent";
return PartialView("~/Views/Shared/CaptchaGenerate.cshtml");
}
ModelState.AddModelError("", "there is some error");
ViewBag.CaptchaInvalid = "";
ViewBag.Successfully = "";
return PartialView("~/Views/Shared/CaptchaGenerate.cshtml");
}