I am filling my dropdownlist with items from Enum.How can I get the index of enum items to dropdown list ?

Here is my Enum
Code:
public enum Colors{ red,blue,green,yellow,orange,white,black,Teal,Custom }
Here is my dropdownlist
Code:
 @Html.DropDownList("SelectedColourId", Model.ColourList, "(Select one Color)")
Here is my ViewModel
Code:
 myPageViewModel:BasicViewModel
...