@using (Html.BeginForm())
{
    @Html.AntiForgeryToken()

    <div class="form-horizontal" style="padding:20px 10px;">
        <h2>Edit User Details</h2>
        @Html.ValidationSummary(true, "", new { @class = "text-danger" })
        <div class="form-group">
            @Html.LabelFor(model => model.Username, htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                @Html.EditorFor(model => model.Username, new { htmlAttributes = new { @class = "form-control", @readonly = "readonly" } })
            </div>
        </div>

        <div class="form-group">
            @Html.LabelFor(model => model.CreatedOn, htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                @Html.EditorFor(model => model.CreatedOn, new { htmlAttributes = new { @class = "form-control", @readonly = "readonly" } })
            </div>
        </div>

        <div class="form-group">
            @Html.LabelFor(model => model.Role, htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                @Html.DropDownListFor(model => model.SelectedRole, new SelectList(Model._RolesList, "Value", "Text", Model.RoleId))
                @Html.ValidationMessageFor(model => model.SelectedRole, "", new { @class = "text-danger" })
            </div>
        </div>
        @Html.HiddenFor(model => model.RoleId)
        @Html.HiddenFor(model => model.UserId)

        <div class="form-group">
            <div class="col-md-offset-2 col-md-10">
                <input type="submit" value="Save" class="btn btn-default" />
            </div>
        </div>
    </div>
}

<div>
    @Html.ActionLink("Back to List", "Index")
</div>

<script src="~/Scripts/jquery-1.10.2.min.js"></script>
<script src="~/Scripts/jquery.validate.min.js"></script>
<script src="~/Scripts/jquery.validate.unobtrusive.min.js"></script>

public ActionResult Edit(int userid)
 {
            UserModel result = this._webClient.DownloadData<UserModel>("getregistereduser",new { Userid = userid }, false);
            EditUserModel _edituser = new EditUserModel();
            _edituser.UserId = result.UserId;
            _edituser.Username = result.Username;
            _edituser.CreatedOn = result.CreatedOn;
            _edituser.Role = result.Role;
            _edituser.RoleId = result.RoleId;
            RolesList _rolelist = this._webClient.DownloadData<RolesList>("getuserroles", null, false);
            foreach (var item in _rolelist._UserRoles)
            {
                _edituser._RolesList.Add(new SelectListItem()
                {
                    Text = item.Role,
                    Value = item.Id.ToString(),
                    Selected = (item.Id == result.RoleId ? true:false),

                });
            }
            return View(_edituser);
        }

[HttpPost]
        public ActionResult Edit(EditUserModel user)
        {
            if(ModelState.IsValid)
            {
                if(user.SelectedRole != user.RoleId)
                {
                    API_Status result = this._webClient.UploadData<API_Status>("Admin/edituser", new { Userid = user.UserId, Roleid = user.SelectedRole }, false);
                    if (result == API_Status.Sucess)
                        TempData["Success"] = "Updated Successfully!";
                    else if (result == API_Status.UserAlreadyExist)
                        TempData["Success"] = "Updation cannot be completed";
                    else
                        TempData["Success"] = "Some Error Occured";
                }
                return RedirectToAction("List");
            }
            else
            {
                return View(user);
            }
        }