The ViewData item that has the key 'MY KEY' is of type 'System.String' but must be of type 'IEnumerable'

Question

I am trying to populate a dropdown list from a database mapped with Linq-2-SQL, using ASP.NET MVC 2, and keep getting this error.

I am so confused because I am decla

Answer 1

Try adding a string for the name of your dropdown list as the first parameter, and get the item out of your viewdata:

 <%= Html.DropDownList("SomeDropdownName", (IEnumerable)ViewData["basetype"]) %>

Here is also an extension method you can use so the dropdown list is set up in a similar style to how you have done your other controls:

        public static string DropDownList(this HtmlHelper htmlHelper, Expression> expression, IEnumerable selectList, string optionLabel)
        where TModel : class
    {
        string inputName = ExpressionHelper.GetInputName(expression);
        return htmlHelper.DropDownList(inputName, selectList, optionLabel);
    }

For example

<%= Html.DropDownList(x => x.BaseType, (IEnumerable)ViewData["basetype"], "")%>