LookupItem Class for DropDownLists - .NET Framework

LookupItem Class

public class LookupItem
{
    public virtual string Descrip { get; set; }
    public int ID { get; set; }

    public static string ListToJson(List<LookupItem> items)
    {
        var result = new List<string>();

        foreach (var item in items)
            result.Add(item.ID.ToString() + ":" + item.Descrip);

        return string.Join(";", result.ToArray());
    }
}

LookupItem Extension Methods

public static class LookupManager
{
    public static List<LookupItem> Nullify(this List<LookupItem> result, string nullValue)
    {
        if (nullValue != null)
            result.Insert(0, new LookupItem { Descrip = nullValue, ID = -1 });

        return result;
    }
}