binding dropdownlist in .net mvc razor by viewbag, model and jquery - 3 ways
There is a lot of ways to bind dropdownlist in asp.net mvc (mvc3, mvc4 or later razor syntax .cshtml) and maintaining dropdownlist state during postback some of them given below -
I am taking a simple example to explain this, here is three dropdownlist that is for state, correspondence city of the state and correspondence area of that city, city and area bind at runtime as per state dropdownlist , city dropdownlist selection change respectively
Well for maintating the state during post back just pass FormCollection class as parameter of post postyourad action and rest all the thing model binder will handle, you can also use like this
public ActionResult postyourad(string istateid,string icityid,string iareaid) model binder automatic bind these value with posted form data collection
Controller class ActionResult -
View page .cshtml -
For maintaining state during postback pass mydropdownlist as parameter then model binder automatic bind posted data into it (model binder check name of property and name of the field of posted form data and bind accordingly) or you can use FormCollection Class as above.
Controller Class ActionResult -
View part .cshtml -
View Model -
View part .cshtml -
Controller Class ActionResult -
- Use viewbag property.
- Through view model.
- Use jquery .ajax i.e. asynchronous post back at selected index change of another dropdownlist.
I am taking a simple example to explain this, here is three dropdownlist that is for state, correspondence city of the state and correspondence area of that city, city and area bind at runtime as per state dropdownlist , city dropdownlist selection change respectively
Fill Data To Dropdownlist Using ViewBag Property
Use viewbag property as list container pass your list into a dynamic property of viewbag and use it into view part, first time (Get Request) city and area dropdownlist should be blank so use empty list for blank dropdownlist as below for binding city and area list during postback request use jquery part as given in the end of the post.Well for maintating the state during post back just pass FormCollection class as parameter of post postyourad action and rest all the thing model binder will handle, you can also use like this
public ActionResult postyourad(string istateid,string icityid,string iareaid) model binder automatic bind these value with posted form data collection
Controller class ActionResult -
[HttpGet]
public ActionResult
postyourad()
{
ViewBag.stateList = getState();
ViewBag.cityList = new List<SelectListItem>
{ };
ViewBag.areaList = new List<SelectListItem>
{ };
return View( );
}
//State management during
postback bind again
[HttpPost]
public ActionResult
postyourad(FormCollection value)
{
ViewBag.stateList = getState(value["istateid"]);
ViewBag.cityList = getCity(value["istateid"],
value["icityid"]);
ViewBag.areaList = getArea(value["istateid"],
value["icityid"], value["iareaid"]);
return View();
}
@{
ViewBag.Title = "dropdownlist bind demo with viewbag";
Layout = "~/Views/Shared/_Layout.cshtml";
}
@using (Html.BeginForm()) {
@Html.DropDownList("istateid", (SelectList)ViewBag.stateList, "--Choose Your State--")
@Html.DropDownList("icityid", (IEnumerable<SelectListItem>)ViewBag.cityList, "--Choose Your City--")
@
<input type="submit" value="submit" />
}
Bind Dropdownlist Using View Model
below is the example of binding dropdownlist through view model named mydropdownlist it have three property and three method return as SelectList type, just pass mydropdownlist class object to view and bind as given in view part below.For maintaining state during postback pass mydropdownlist as parameter then model binder automatic bind posted data into it (model binder check name of property and name of the field of posted form data and bind accordingly) or you can use FormCollection Class as above.
Controller Class ActionResult -
[HttpGet]
public ActionResult
postyourad()
{
return View(new mydropdownlist());
}
//State management during
postback model binder automatic bind the propery of dropdownlist
[HttpPost]
public ActionResult
postyourad(mydropdownlist ddlListPostData)
{
//mydropdownlist ddlList = new mydropdownlist() { istateid =
ddlListPostData.istateid, icityid = ddlListPostData.icityid, iareaid =
ddlListPostData.iareaid };
return View(ddlListPostData);
}
@model
ECommerce.Models.
@{
ViewBag.Title =
Layout = "~/Views/Shared/_Layout.cshtml";
}
@using (Html.BeginForm()) {
@Html.DropDownListFor(x
=> x.istateid, Model.getState() , "--Choose Your State--")
@Html.DropDownListFor(x
=> x.icityid, Model.getCity(), "--Choose Your City--")
@Html.DropDownListFor(x
=> x.iareaid, Model.getArea(),"--Choose Your Area--")
<input type="submit"
value="submit"
/>
}
using System;
using
System.Collections.Generic;
using System.Linq;
using System.Web;
using
System.ComponentModel.DataAnnotations;
using System.Web.Mvc;
namespace ECommerce.Models
{
public class
mydropdownlist
{
MyDbContext _db = null;
public mydropdownlist() { _db = new MyDbContext(); }
[Required]
public virtual string iareaid { get;
set; }
[Required]
public virtual string icityid { get;
set; }
[Required]
public virtual string istateid { get;
set; }
public SelectList
getState()
{
IEnumerable<SelectListItem>
stateList = (from m in
_db.mstrstates where m.bstatus == true select
m).AsEnumerable().Select(m => new SelectListItem() { Text = m.vstate, Value =
m.istateid.ToString() });
return new SelectList(stateList, "Value",
"Text", istateid);
}
public SelectList
getCity()
{
IEnumerable<SelectListItem>
cityList = new List<SelectListItem>();
if (!string.IsNullOrEmpty(istateid))
{
int _stateId = Convert.ToInt32(istateid);
cityList = (from m in _db.mstrcities where
m.bstatus == true && m.istateid ==
_stateId select m).AsEnumerable().Select(m
=> new SelectListItem()
{ Text = m.vcity, Value = m.icityid.ToString() });
}
return new SelectList(cityList, "Value",
"Text", icityid);
}
public SelectList
getArea()
{
IEnumerable<SelectListItem>
areaList = new List<SelectListItem>();
if (!string.IsNullOrEmpty(istateid)
&& !string.IsNullOrEmpty(icityid))
{
int _cityId = Convert.ToInt32(icityid);
int _stateId = Convert.ToInt32(istateid);
areaList = (from m in _db.mstrareas join
p in _db.mstrcities on
m.icityid equals p.icityid where m.bstatus == true
&& m.icityid == _cityId && p.istateid == _stateId select m).AsEnumerable().Select(m => new SelectListItem()
{ Text = m.vareaname, Value = m.iareaid.ToString() });
}
return new SelectList(areaList, "Value",
"Text", iareaid);
}
}
}
Bind Data To Dropdownlist using jquery .ajax post in selection change event
If you want to bind dropdownlist according to posted data during postback (asynchronously) in selected item change event of another dropdownlist then you can do this through jquery .ajax method and through JsonResult (JsonResult - Serializes a given ViewData object to JSON format) as given below -View part .cshtml -
$("#istateid").change(function () {
$.ajax({
type: "POST",
url: '@Url.Action("getCityJson",
"PostAd")',
data: { stateId: $("#istateid > option:selected").attr("value") },
success: function (data) {
var items = [];
items.push("<option>--Choose Your Area--</option>");
$.each(data, function () {
items.push("<option value=" + this.Value + ">" + this.Text + "</option>");
});
$("#icityid").html(items.join(' '));
}
})
});
$("#icityid").change(function () {
$.ajax({
type:"POST",
url: '@Url.Action("getAreaJson",
"PostAd")',
data: { cityId: $("#icityid >
option:selected").attr("value"),
stateId: $("#istateid >
option:selected").attr("value")
},
success: function (data) {
var items = [];
items.push("<option>--Choose Your Area--</option>");
$.each(data, function () {
items.push("<option value="
+ this.Value + ">"
+ this.Text + "</option>");
});
$("#iareaid").html(items.join(' '));
}
})
});
[HttpPost]
public JsonResult
getStateJson(string selectStateId = null)
{
return Json(getState(selectStateId));
}
public SelectList
getState(string selectStateId = null)
{
IEnumerable<SelectListItem>
stateList = (from m in
_db.mstrstates where m.bstatus == true select
m).AsEnumerable().Select(m => new SelectListItem() { Text = m.vstate, Value =
m.istateid.ToString() });
return new SelectList(stateList, "Value",
"Text", selectStateId);
}
[HttpPost]
public JsonResult
getCityJson(string stateId, string selectCityId=null)
{
return Json(getCity(stateId, selectCityId));
}
public SelectList
getCity(string stateId, string selectCityId = null)
{
IEnumerable<SelectListItem>
cityList = new List<SelectListItem>();
if (!string.IsNullOrEmpty(stateId))
{
int _stateId = Convert.ToInt32(stateId);
cityList = (from m in _db.mstrcities where
m.bstatus == true && m.istateid ==
_stateId select m).AsEnumerable().Select(m
=> new SelectListItem()
{ Text = m.vcity, Value = m.icityid.ToString() });
}
return new SelectList(cityList, "Value",
"Text", selectCityId);
}
[HttpPost]
public JsonResult
getAreaJson(string stateId, string cityId, string
selectAreaId = null)
{
return Json(getArea(stateId, cityId, selectAreaId));
}
public SelectList
getArea(string stateId, string cityId, string selectAreaId
= null)
{
IEnumerable<SelectListItem>
areaList = new List<SelectListItem>();
if (!string.IsNullOrEmpty(stateId)
&& !string.IsNullOrEmpty(cityId))
{
int _cityId = Convert.ToInt32(cityId);
int _stateId = Convert.ToInt32(stateId);
areaList = (from m in _db.mstrareas join
p in _db.mstrcities on
m.icityid equals p.icityid where m.bstatus == true
&& m.icityid == _cityId && p.istateid == _stateId select m).AsEnumerable().Select(m => new SelectListItem()
{ Text = m.vareaname, Value = m.iareaid.ToString() });
}
return new SelectList(areaList, "Value",
"Text", selectAreaId);
}
