Mark Mark - 1 month ago 21
ASP.NET (C#) Question

MVC SelectList combining multiple columns in text field

How would I generate a select list, where the text field, is made up of two or more text columns, eg: Where I have a Description and Rate field in my database, I want to combine these to show:

Large--£200
Medium--£150
Small--£100


Controller code is:

var stands = db.Stands.Where(s => s.ExhibitorID == null).ToList();
ViewBag.StandID = new SelectList(stands,"StandID", "Description" + "-- £" + "Rate");


...and my view is (currently):

<div class="editor-field">
@Html.DropDownList("StandID", "--Select--")
</div>


...but the "Description" + "-- £" + "Rate"); won't run:


DataBinding:
'System.Data.Entity.DynamicProxies.Stand_63F8C9F623B3C0E57D3008A57081AFCD9C39E1A6B79B0380B60840F1EFAE9DB4'
does not contain a property with the name 'Description--£Rate'.


Thanks for any help,

Mark

Answer

You could create a new anonymous class using a simple LINQ projection, and then use the SelectList(IEnumerable, string, string) constructor overload to specify the value and text fields to be used for the <option> elements i.e.:

var stands = 
  db.Stands
    .Where(s => s.ExhibitorID == null)
    .Select(s => new 
     { 
       StandID = s.StandID,
       Description = string.Format("{0}-- £{1}", s.Description, s.Rate) 
     })
    .ToList();

ViewBag.StandID = new SelectList(stands, "StandID", "Description")

Edit

In C#6 and later, string interpolation makes for better reading than string.Format

   ...
   Description = $"{s.Description}-- £{s.Rate}"

If you project to a strong ViewModel class name (instead of to an anonymous class), you will undoubtedly want to replace the magic strings with the safety of the nameof operator:

ViewBag.StandID = new SelectList(stands, nameof(Stand.StandID), nameof(Stand.Description));