//in controller
ViewBag.Categories = categoryRepository.GetAllCategories().ToList();
//in view
@Html.DropDownList("Cat", new SelectList(ViewBag.Categories,"ID", "CategoryName"))
How can I make it so that by default it says "-Select Category-"
And validate to check something is selected (client and on the model)
Thanks
I just can't believe that there are people still using ViewData/ViewBag in ASP.NET MVC 3 instead of having strongly typed views and view models:
public class MyViewModel
{
[Required]
public string CategoryId { get; set; }
public IEnumerable<Category> Categories { get; set; }
}
and in your controller:
public class HomeController: Controller
{
public ActionResult Index()
{
var model = new MyViewModel
{
Categories = Repository.GetCategories()
}
return View(model);
}
[HttpPost]
public ActionResult Index(MyViewModel model)
{
if (!ModelState.IsValid)
{
// there was a validation error =>
// rebind categories and redisplay view
model.Categories = Repository.GetCategories();
return View(model);
}
// At this stage the model is OK => do something with the selected category
return RedirectToAction("Success");
}
}
and then in your strongly typed view:
@Html.DropDownListFor(
x => x.CategoryId,
new SelectList(Model.Categories, "ID", "CategoryName"),
"-- Please select a category --"
)
@Html.ValidationMessageFor(x => x.CategoryId)
Also if you want client side validation don't forget to reference the necessary scripts:
<script src="@Url.Content("~/Scripts/jquery.validate.js")" type="text/javascript"></script>
<script src="@Url.Content("~/Scripts/jquery.validate.unobtrusive.js")" type="text/javascript"></script>
ViewData/ViewBag especially in Dropdownlist context ?
There is an overload with 3 arguments. Html.DropdownList(name, selectList, optionLabel)
Update: there was a typo in the below code snippet.
@Html.DropDownList("Cat", new SelectList(ViewBag.Categories,"ID", "CategoryName"), "-Select Category-")
For the validator use
@Html.ValidationMessage("Cat")
@Html.DropDownList("Cat", new SelectList(ViewBag.Categories, "ID", "CategoryName"), "-Select Category-")For ListBox / DropDown in MVC5 - i've found this to work for me sofar:
in Model:
[Required(ErrorMessage = "- Select item -")]
public List<string> SelectedItem { get; set; }
public List<SelectListItem> AvailableItemsList { get; set; }
in View:
@Html.ListBoxFor(model => model.SelectedItem, Model.AvailableItemsList)
@Html.ValidationMessageFor(model => model.SelectedItem, "", new { @class = "text-danger" })
Example from MVC 4 for dropdownlist validation on Submit using Dataannotation and ViewBag (less line of code)
Models:
namespace Project.Models
{
public class EmployeeReferral : Person
{
public int EmployeeReferralId { get; set; }
//Company District
//List
[Required(ErrorMessage = "Required.")]
[Display(Name = "Employee District:")]
public int? DistrictId { get; set; }
public virtual District District { get; set; }
}
namespace Project.Models
{
public class District
{
public int? DistrictId { get; set; }
[Display(Name = "Employee District:")]
public string DistrictName { get; set; }
}
}
EmployeeReferral Controller:
namespace Project.Controllers
{
public class EmployeeReferralController : Controller
{
private ProjDbContext db = new ProjDbContext();
//
// GET: /EmployeeReferral/
public ActionResult Index()
{
return View();
}
public ActionResult Create()
{
ViewBag.Districts = db.Districts;
return View();
}
View:
<td>
<div class="editor-label">
@Html.LabelFor(model => model.DistrictId, "District")
</div>
</td>
<td>
<div class="editor-field">
@*@Html.DropDownList("DistrictId", "----Select ---")*@
@Html.DropDownListFor(model => model.DistrictId, new SelectList(ViewBag.Districts, "DistrictId", "DistrictName"), "--- Select ---")
@Html.ValidationMessageFor(model => model.DistrictId)
</div>
</td>
Why can't we use ViewBag for populating dropdownlists that can be validated with Annotations. It is less lines of code.
