MVC Dropdown Binding in the View

DropDownListFor:

@Html.DropDownListFor(model => model.RoleID, new SelectList(ViewBag.Role as System.Collections.IEnumerable, "id", "roleName"), "Select", new { id = "ddlRoles", @class = "ft-sb validate[required]" })

DropDownList:

var listBranch = new List<SelectListItem>();

listBranch.Add(new SelectListItem { Text = "--Select--", Value = string.Empty });

     foreach (var agents in ViewBag.BranchList)

            {

                listBranch.Add(new SelectListItem { Text = agents, Value = agents });

            }

@Html.DropDownList("ddlBranchTypeValues", listBranch, new { @class = "ft-tb", @id = "ddlBranchTypeValues" })