Select distinct using LINQ and bound to a dropdown list with id and display name

Question

Hi,
On one of my sharepoint page, I want to populate dropdown list with countries, namely
<asp:DropDownList ID="ddlCountry" runat ="server"></asp:DropDownList>
In the code, I use LINQ:
 var country = (from p in dc.ProvCountries
                               select p.country_code ).Distinct();
            ddlCountry.DataSource = country;
                ddlCountry.DataBind();
I want the country_code to be  the ID, while the country_name will be the display name in the dropdown, how can that be done?
Thanks in advance.

Answer 1

Hi,
The following code for your check.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace WebApplicationLib
public partial class _Default : Page
protected void Page_Load(object sender, EventArgs e)
List<ProvCountries> list = new List<ProvCountries>();
list.Add(new ProvCountries { country_code = "201", country_name = "A"});
list.Add(new ProvCountries { country_code = "201", country_name = "B" });
list.Add(new ProvCountries { country_code = "202", country_name = "C" });
list.Add(new ProvCountries { country_code = "202", country_name = "D" });
var country = (from p in list select new { p.country_code, p.country_name }).DistinctBy(p => p.country_code).ToList();
ddlCountry.DataSource = country;
ddlCountry.DataValueField = "country_code";
ddlCountry.DataTextField = "country_name";
ddlCountry.DataBind();
ddlCountry.Items.Insert(0, new ListItem("Please select", ""));
class ProvCountries
public string country_code { get; set; }
public string country_name { get; set; }
static class DataDistinct
public static IEnumerable<TSource> DistinctBy<TSource, TKey>(this IEnumerable<TSource> source, Func<TSource, TKey> keySelector)
HashSet<TKey> seenKeys = new HashSet<TKey>();
foreach (TSource element in source)
if (seenKeys.Add(keySelector(element)))
yield return element;
Thanks,
Dennis Guo
TechNet Community Support
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Dennis Guo
TechNet Community Support