In my controller i am returning list of my object with specific property:

public ActionResult Index()
{
    List<MyObject> list = db.MyObjects.Where(x => x.family == "Web").ToList();
    ViewBag.Files = new SelectList(list, "Id", "protocol");
    return View();
}

This is my object:

public class MyObject
{
    public int id { get; set; }
    public string fileName { get; set; }
    public string browser { get; set; }    
    public string protocol { get; set; }    
    public string family { get; set; }
}

Index.cshtml:

@Html.DropDownList("File", new SelectList(ViewBag.Files, "Id", "protocol_site"), "Select webmail site", new { style = "vertical-align:middle;" })

And i try to made 2 changes with no succeed:

1. Remove all the duplication protocol from my DropDownListfor exapmle if i have 10 objects : 9 is doc protocol and 1 pdf i wand to see in my DropDownList only 2 items: DOC and PDF and not all the 10 items.

2. Sort this DropDownList in alphabet order