Queries realted to Dropdown list in MVC - asp.net-mvc

Question

I am a new to ASP.NET MVC, I am developing an application. I want to bind the data in the drop down list in create view.
How to bind the data in the drop down? I have go through many question and answers here...
I have seen usually everyone suggested to use List<SelectListItem> what is its purpose?
Do I need to use ViewModel while binding the data to drop down list?
Can I get simple example where data get bind in the dropdown using viewbag?
I have created a list in controller
List<string> items = new List<string>();
and I want to pass this list to view using viewbag and simply want to bind to drop down list.
How to do this ?

Answer 1

I'd suggest using a ViewModel as it makes interaction with user input so much easier. Here's an example of how you might bind data from your ViewModel to a drop down in your View. First, the ViewModel:
public class CrowdViewModel
{
public string SelectedPerson { get; set;}
public IEnumerable<SelectListItem> People { get; set; }
}
So yes, you're right - use a collection of SelectListItems. I'm guessing in your case, the SelectListItem's Value and Text property will be the same. You could turn your List into IEnumerable like this:
[HttpGet]
public ActionResult Home()
{
// get your list of strings somehow
// ...
var viewModel = new CrowdViewModel
{
People = items.Select(x => new SelectListItem { Text = x, Value = x })
}
return View(viewModel);
}
Now you need to bind that ViewModel's property to the DropDown on your view. If you're using the Razor ViewEngine, the code will look something like this:
#model MyApp.ViewModels.CrowdViewModel
#using (Html.BeginForm())
{
#Html.DropDownListFor(model => model.SelectedPerson, Model.People)
}
Now when you post that form, MVC will bind the selected value to the ViewModel's SelectedPerson property!
[HttpPost]
public ActionResult Home(CrowdViewModel viewModel)
{
// viewModel.SelectedPerson == whatever the user selected
// ...
}
Easy as that!
Update:
If you really want to use the ViewBag (don't do it), you can pass your list through from your Controller action like so:
[HttpGet]
public ActionResult Home()
{
ViewBag.People = new List<string> { "Bob", "Harry", "John" };
return View();
}
And then create a SelectList on your View:
#Html.DropDownList("SelectedPerson", new SelectList(ViewBag.People, Model))