public class CustomValidators
{
    [Required]
    [Required(ErrorMessage = "State Required")]
    public string drpStateId { set; get; }

    public System.Web.Mvc.SelectList drpState { set; get; }
    [Required(ErrorMessage ="Region Required")]
    public string txtRegion { set; get; }
}

@model InterviewTest.Models.CustomValidators

@{
    ViewBag.Title = "Custom Validator";
    Layout = "~/Views/_Layout.cshtml";
}

<p>@Html.ActionLink("< Back", "Index")</p>

@using (Html.BeginForm("CustomValidatorPost"))
{
    @Html.ValidationSummary()
    <div class="container-fluid">
        <div class="row">
            <div class="col-sm-3">
                <div class="form-group">
                    @Html.DropDownListFor(c => c.drpStateId, Model.drpState, "", new { @class = "form-control" })
                </div>
            </div>

            <div class="col-sm-6">
                <div class="form-group">
                    @Html.TextBoxFor(x => Model.txtRegion, new { @class = "form-control" })
                    @*<input type="text" id="txtRegion" name="txtRegion" class="form-control" />*@
                </div>
            </div>

            <div class="col-sm-3">
                <button type="submit" name="btnSubmit" id="btnSubmit" class="btn btn-default">Submit</button>
            </div>
        </div>
    </div>
}