Question

I’m trying to implement a editor template for Nullable<bool> to instead to appear true or false, appears “Si” or “No”. This is what I have so far.

@model Nullable<bool>

@{
   var listItems = new List<System.Web.UI.WebControls.ListItem>();
   listItems.Add(new System.Web.UI.WebControls.ListItem{Text="Si", Value="true"});
   listItems.Add(new System.Web.UI.WebControls.ListItem{Text="No", Value="false"});         
}


@Html.DropDownList( model => model.Value, listItems)

And It’s throws this error Cannot convert lambda expression to type 'string' because it is not a delegate type. I can’t see the error what i’m doing wrong???

Answer 1

The DropDownList helper takes a string as first argument, not a lambda expression. Use DropDownListFor and make sure that the second argument is an IEnumerable<SelectListItem>, which your code isn’t:

@model Nullable<bool>
@{
    var listItems = new[]
    {
        new SelectListItem { Value = "true", Text = "Si" },
        new SelectListItem { Value = "false", Text = "No" }
    };
}
@Html.DropDownListFor(model => model.Value, listItems)

You can forget about System.Web.UI.WebControls.ListItem in an ASP.NET MVC application. That’s a classic WebForms stuff.