Question

I have this code:

@Html.DropDownList("ddlCouponsAppointment",
    Model.Coupons.Select(a => new SelectListItem {
                                    Text = a.Name,
                                    Value = a.CouponId.ToString(),
                                    Selected = (a.CouponId == Model.CouponForAppointmentReminders.CouponId)
                        }), 
    "None",
    new { @class = "normalcell" })

This has worked for ages. Now, it throws an error, which a google tells me is because I am not allowed to call ToString on an entity that is being mapped to a class ( this class has not changed, so I am at a loss how it worked before ). So I added a property called CouponIdStr, which is a string representation. This does not work ( blows up b/c the property is not mapped to the DB ). I tried making value equal string.Empty + a.CouponId ( as C# would concatenate that as a string ). It blows up.

So I tried this:

@Html.DropDownList("ddlCouponsAppointment",
    new SelectList(Model.Coupons,
        "Name",
        "CouponId",
        Model.CouponForAppointmentReminders.CouponId),
    "None",
    new { @class = "normalcell" })

This works, but does not show the selected item. Does anyone have any suggestions ?

Answer 1

step 1. Create a ViewModel that has the selected value

step 2. In that ViewModel have the list of items you want in the select list

public class ViewModel {      
   public int Selected {get;set;}
   public IEnumerable<Option> Options {get;set;}
}

step 3. In your view, use the DisplayFor method

Html.DisplayFor(m => m.Selected, new SelectList(Model.Options, "Id", "Display"));

There you have it, when the dropdown renders, it will have the selected value selected!

Good Luck!