How to reuse list items for asp:DropDownList controls?

Question

I have an .aspx page which contains two <asp:DropDownList> controls which are filled with static items like so:

<asp:DropDownList ID="ddl1" ...>
    <asp:ListItem Value="A" Text="..." />
    <asp:ListItem Value="B" Text="..." />
    ....
    <asp:ListItem Value="X" Text="..." />
</asp:DropDownList>

.....

<asp:DropDownList ID="ddl2" ...>
    <asp:ListItem Value="A" Text="..." />
    <asp:ListItem Value="B" Text="..." />
    ....
    <asp:ListItem Value="X" Text="..." />
</asp:DropDownList>

The list items for ddl1 and ddl2 are the same. As such, I would like to reuse them and remove the duplication.

I could fill the combos in the code behind .aspx.cs but I really don't want to have some dumb data in there filling plain combos. I just want the logic of the page there.

Is there a way to resue the list items inside the .aspx?

Brett · Accepted Answer · 2011-07-07 16:38:38Z

Create a class to represent the data in the DDL and then call a get method. Use the same ObjectDataSource for both DDL's or use separate ObjectDataSources. You could optimize the class to use static members, but it's probably overkill.

This strategy would nicely refactor into a db call in the future...

In the Web Form:

<asp:ObjectDataSource ID="obj1" runat="server"
    TypeName="WebApplication1.Data.MyDdlItem"
    SelectMethod = "GetAll" />
<asp:DropDownList ID="ddl1" runat="server" DataSourceID="obj1" DataTextField="Name" DataValueField="Id" />
<asp:DropDownList ID="ddl2" runat="server" DataSourceID="obj1" DataTextField="Name" DataValueField="Id" />

The corresponding Object:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

namespace WebApplication1.Data
{
    public class MyDdlItem
    {
        public string Id { get; set; }
        public string Name { get; set; }

        public static List<MyDdlItem> GetAll()
        {
            List<MyDdlItem> list = new List<MyDdlItem>();
            list.Add(new MyDdlItem { Id = "1", Name = "Option 1" });
            list.Add(new MyDdlItem { Id = "2", Name = "Option 2" });
            list.Add(new MyDdlItem { Id = "3", Name = "Option 3" });
            list.Add(new MyDdlItem { Id = "4", Name = "Option 4" });
            return list;
        }
    }
}

Ovais Khatri · Accepted Answer · 2011-07-07 15:56:43Z

1

Just create a datatable and bind both dropdown with the same datatable.

answered Jul 7, 2011 at 15:56

Ovais Khatri

3,21118 silver badges15 bronze badges

Comments

MuthuKumaran · Accepted Answer · 2011-07-07 16:09:16Z

0

Why don't you use Java script array to bind them later to both the drop downs?

<script>
  var arr = new Array(new Array('A','value1'),new Array('B','value2'),new Array('C','value3'));
var elem = document.getElementById("ddl1");
var elem1 = document.getElementById("ddl2");
 for(i=0;i<arr.length;i++)
 {
    elem.add(new Option(arr[i][0, 1], arr[i][0, 0]),false);
    elem1.add(new Option(arr[i][0, 1], arr[i][0, 0]),false);
 }
</script>

answered Jul 7, 2011 at 16:09

MuthuKumaran

1037 bronze badges

1 Comment

meme Over a year ago

Because that causes other problems (stackoverflow.com/questions/228969/…) and I don't need the hussle

Gage · Accepted Answer · 2011-07-07 16:11:20Z

0

Try something like ddl2.DataSource=ddl1.DataSource then once ddl1 has all its items ddl2 should as well.

answered Jul 7, 2011 at 16:11

Gage

7,5239 gold badges50 silver badges77 bronze badges

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