Hi Sumeet,

Using the below article i have created the example.

Cascading (Dependent) Country State City DropDownLists using jQuery AJAX in ASP.Net MVC

Check this example. Now please take its reference and correct your code.

Namespaces

C#

using System.Configuration;
using System.Data.SqlClient;

VB.Net

Imports System.Configuration
Imports System.Data.SqlClient

Model

C#

using System.ComponentModel;
using System.Web.Mvc;

public class Register
{
    public Register()
    {
        this.States = new List<SelectListItem>();
        this.Cities = new List<SelectListItem>();
    }
    public List<SelectListItem> States { get; set; }
    public List<SelectListItem> Cities { get; set; }

    [DisplayName("Full Name")]
    public string Name { get; set; }
    [DisplayName("State")]
    public string State { get; set; }
    [DisplayName("City")]
    public string City { get; set; }
    [DisplayName("Gender")]
    public string Gender { get; set; }
    [DisplayName("Mobile")]
    public Int64 Mobile { get; set; }
}

VB.Net

Imports System.ComponentModel
Imports System.Web.Mvc

Public Class Register
    Public Sub New()
        Me.States = New List(Of SelectListItem)()
        Me.Cities = New List(Of SelectListItem)()
    End Sub

    Public Property States As List(Of SelectListItem)
    Public Property Cities As List(Of SelectListItem)
    <DisplayName("Full Name")>
    Public Property Name As String
    <DisplayName("State")>
    Public Property State As String
    <DisplayName("City")>
    Public Property City As String
    <DisplayName("Gender")>
    Public Property Gender As String
    <DisplayName("Mobile")>
    Public Property Mobile As Int64
End Class

Controller

C#

public class HomeController : Controller
{
    // GET: /Home/
    public ActionResult Index()
    {
        return View();
    }

    [HttpGet]
    public ActionResult Create()
    {
        Register model = new Register();
        model.States = PopulateDropDown("SELECT StateId, StateName FROM States", "StateName", "StateId");
        return View(model);
    }

    [HttpPost]
    public JsonResult AjaxMethod(string type, int? value)
    {
        type = "State";
        value = 1;
        Register model = new Register();
        switch (type)
        {
            case "State":
                model.Cities = PopulateDropDown("SELECT CityId, CityName FROM Cities WHERE StateId = " + value, "CityName", "CityId");
                break;
        }
        return Json(model);
    }

    [HttpPost]
    public ActionResult Create(Register registerModel)
    {
        // Do your Task.   
        return RedirectToAction("Create");
    }

    private static List<SelectListItem> PopulateDropDown(string query, string textColumn, string valueColumn)
    {
        List<SelectListItem> items = new List<SelectListItem>();
        string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
        using (SqlConnection con = new SqlConnection(constr))
        {
            using (SqlCommand cmd = new SqlCommand(query))
            {
                cmd.Connection = con;
                con.Open();
                using (SqlDataReader sdr = cmd.ExecuteReader())
                {
                    while (sdr.Read())
                    {
                        items.Add(new SelectListItem
                        {
                            Text = sdr[textColumn].ToString(),
                            Value = sdr[valueColumn].ToString()
                        });
                    }
                }
                con.Close();
            }
        }

        return items;
    }
}

VB.Net

Public Class HomeController
    Inherits Controller

    Public Function Index() As ActionResult
        Return View()
    End Function

    <HttpGet>
    Public Function Create() As ActionResult
        Dim model As Register = New Register()
        model.States = PopulateDropDown("SELECT StateId, StateName FROM States", "StateName", "StateId")
        Return View(model)
    End Function

    <HttpPost>
    Public Function AjaxMethod(ByVal type As String, ByVal value As Integer?) As JsonResult
        Dim model As Register = New Register()
        Select Case type
            Case "State"
                model.Cities = PopulateDropDown("SELECT CityId, CityName FROM Cities WHERE StateId = " & value, "CityName", "CityId")
        End Select

        Return Json(model)
    End Function

    <HttpPost>
    Public Function Create(ByVal registerModel As Register) As ActionResult
        Return RedirectToAction("Create")
    End Function

    Private Shared Function PopulateDropDown(ByVal query As String, ByVal textColumn As String, ByVal valueColumn As String) As List(Of SelectListItem)
        Dim items As List(Of SelectListItem) = New List(Of SelectListItem)()
        Dim constr As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString
        Using con As SqlConnection = New SqlConnection(constr)
            Using cmd As SqlCommand = New SqlCommand(query)
                cmd.Connection = con
                con.Open()
                Using sdr As SqlDataReader = cmd.ExecuteReader()
                    While sdr.Read()
                        items.Add(New SelectListItem With {
                            .Text = sdr(textColumn).ToString(),
                            .Value = sdr(valueColumn).ToString()
                        })
                    End While
                End Using
                con.Close()
            End Using
        End Using

        Return items
    End Function
End Class

View

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title>Create</title>
    <script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
    <script type="text/javascript" src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.2/js/bootstrap.min.js"></script>
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.2/css/bootstrap.min.css" />
    <script type="text/javascript">
        $(function () {
            $("select").each(function () {
                if ($(this).find("option").length <= 1) {
                    $(this).attr("disabled", "disabled");
                }
            });

            $("#State").change(function () {
                var value = 0;
                if ($(this).val() != "") {
                    value = $(this).val();
                }
                var id = $(this).attr("id");
                $.ajax({
                    type: "POST",
                    url: "/Home/AjaxMethod",
                    data: '{type: "' + id + '", value: ' + value + '}',
                    contentType: "application/json; charset=utf-8",
                    dataType: "json",
                    success: function (response) {
                        var dropDownId;
                        var list;
                        switch (id) {
                            case "State":
                                dropDownId = "#City";
                                list = response.Cities;
                                DisableDropDown("#City");
                                PopulateDropDown("#City", list);
                                break;
                        }

                    },
                    failure: function (response) {
                        alert(response.responseText);
                    },
                    error: function (response) {
                        alert(response.responseText);
                    }
                });
            });
        });

        function DisableDropDown(dropDownId) {
            $(dropDownId).attr("disabled", "disabled");
            $(dropDownId).empty().append('<option selected="selected" value="0">Please select</option>');
        }

        function PopulateDropDown(dropDownId, list) {
            if (list != null && list.length > 0) {
                $(dropDownId).removeAttr("disabled");
                $.each(list, function () {
                    $(dropDownId).append($("<option></option>").val(this['Value']).html(this['Text']));
                });
            }
        }
    </script>
</head>
<body>
    <div>
        <%using (Html.BeginForm("Create", "Home", FormMethod.Post))
          { %>
        <div class="form-horizontal">
            <h4>
                Registration For Yatra Parchi</h4>
            <hr />
            <div class="form-group">
                <div class="col-md-2">
                    <%:Html.LabelFor(model => model.Name)%>
                </div>
                <div class="col-md-10">
                    <%:Html.EditorFor(model => model.Name)%>
                </div>
            </div>
            <div class="form-group">
                <div class="col-md-2">
                    <%:Html.LabelFor(model => model.Gender)%>
                </div>
                <div class="col-md-10">
                    Male
                    <%:Html.RadioButtonFor(model=>model.Gender,"Male") %>
                    Female
                    <%:Html.RadioButtonFor(model=>model.Gender,"Female") %>
                </div>
            </div>
            <div class="form-group">
                <div class="col-md-2">
                    <%:Html.LabelFor(model => model.State)%>
                </div>
                <div class="col-md-10">
                    <%:Html.DropDownListFor(model => model.State, Model.States, "Please select")%>
                </div>
            </div>
            <div class="form-group">
                <div class="col-md-2">
                    <%:Html.LabelFor(model => model.City)%>
                </div>
                <div class="col-md-10">
                    <%:Html.DropDownListFor(model => model.City, Model.Cities, "Please select")%>
                </div>
            </div>
            <div class="form-group">
                <div class="col-md-2">
                    <%:Html.LabelFor(model => model.Mobile)%>
                </div>
                <div class="col-md-10">
                    <%:Html.EditorFor(model => model.Mobile)%>
                </div>
            </div>
        </div>
        <div class="form-group">
            <div class="col-md-offset-2 col-md-10">
                <input type="submit" value="Create" class="btn btn-default" />
            </div>
        </div>
        <%} %>
    </div>
</body>
</html>

Screenshot

The Form

On Submit