How to set the selected item in an MVC Dropdownlist

The first parameter to the Html.DropDownList needs to be a name that does not match the name in your model. Below I used "OptionId" instead of "Options".

View

<%= Html.DropDownList("OptionId",Model.Options) %>

Controller

SelectListItem item1 = new SelectListItem();

item1.Text = "Red";

item1.Value = "Red";

item1.Selected = false;

viewModel.Options.Add(item1);

SelectListItem item2 = new SelectListItem();

item2.Text = "Green";

item2.Value = "Green";

item2.Selected = true;

viewModel.Options.Add(item2);

SelectListItem item3 = new SelectListItem();

item3.Text = "Blue";

item3.Value = "Blue";

item3.Selected = false;

viewModel.Options.Add(item3);