How to postback on index change of ASP.net MVC dropdownlist?

How to postback on index change of ASP.net MVC dropdownlist?

I have found this on internet from this site

http://www.altafkhatri.com/Technical/ASP-NET-MVC-Dropdownlist/How-to-post-back/on-selectedIndexChanged

It is really helpful post. I put this on here future reference.

Steps to create the postback in ASP.Net MVC dropdownlist selectedindex change event:

Create a controller - Dropdownlist. Paste the code in the section below.
Create a view of the GetDD action binded to the strongly typed object(CoverObject). Paste the code in the section below.


Code in the controller

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.Mvc;

using System.Web.Mvc.Ajax;



namespace MvcApplication1.Controllers

{

public class CoverObject

{

public IList iliSLI;

public string SelectedName { get; set; }

public string Name { get; set; }

public string Address { get; set; }



public string formAction { get; set; }



public CoverObject()

{

iliSLI = new List();

SelectListItem sli = new SelectListItem();

sli.Text = "Altaf";

sli.Value = "1";



iliSLI.Add(sli);



sli = new SelectListItem();

sli.Text = "Krish";

sli.Value = "22";

iliSLI.Add(sli);



sli = new SelectListItem();

sli.Text = "Sameer";

sli.Value = "3333";

iliSLI.Add(sli);



sli = new SelectListItem();

sli.Text = "Iqbal";

sli.Value = "44444";

iliSLI.Add(sli);



sli = new SelectListItem();

sli.Text = "Maimoona";

sli.Value = "5555";

iliSLI.Add(sli);



}

}

public class DropdownlistController : Controller

{

//

// GET: /Dropdownlist/

public ActionResult Index()

{

return View();

}



public ActionResult GetDD()

{

CoverObject co = new CoverObject();

co.formAction = "";

//ViewData["SecretQuestion"] = co.iliSLI;

return View(co);

}



[AcceptVerbs(HttpVerbs.Post)]

public ActionResult GetDD(CoverObject co)

{

CoverObject coNew = new CoverObject();

string indexChangedValue = co.SelectedName;





var item = from it in coNew.iliSLI

where it.Value == co.SelectedName

select it;

item.First().Selected = true;

coNew.Name = item.First().Text;

coNew.Address = co.Address;





if (!string.IsNullOrEmpty(co.formAction) && co.formAction.Equals("Submit Form By Clicking"))

{

// Based on the main submit of the form, it can process and redirect or stay on the same view.

ModelState.AddModelError("_FORM", "Form Submitted by clicking submit button");

}

else//Submitted by dropdownlist index change event

{

//DROPDOWNLIST on selectedIndexChangedEvent Handled hereModelState.AddModelError("_FORM", "Form Submitted by clicking submit button");

ModelState.AddModelError("iliSLI", "Form Submitted by selected Index Change event");

}

return View(coNew);

}

}

}



Code in the aspx file

<%@ Page Language="C#" Inherits="System.Web.Mvc.ViewPage" %>



















<%= Html.ValidationSummary("Form submitted by what event notification:") %>



<% using (Html.BeginForm()) {%>

Fields

Address:

<%= Html.TextBox("co.Address", Model.Address)%>

<%= Html.ValidationMessage("Address", "*") %>

Please select Name:

<%= Html.DropDownList("co.SelectedName", Model.iliSLI, new { onChange = "onSelectedIndexChanged()" })%>

<%= Html.ValidationMessage("iliSLI", "*") %>

Selected Name:

<%= Html.TextBox("Name", Model.Name, new { disabled="true" })%>

<%= Html.ValidationMessage("Name", "*") %>

<% } %>