Example Sitecore control using datasources and Multilists Note: Multilists need to use Sitecore Item IDs find items.

KBListingML.ascx

<%@ Control Language="C#" AutoEventWireup="true" CodeBehind="KnowledgeBaseListing.ascx.cs" Inherits="DigiconNew.layouts.Sublayouts.Controls.KnowledgeBaseListing" %>

<% foreach (var kbcategory in KBCategories)
{
    %>
    <div class="article">
        <div class="article-title">
            <h3>
                <a href='<%= GetURL(kbcategory) %>'><%= kbcategory["Article Title"]%></a>
  		</h3>
        </div>
        <div class="kb-summary"><%= kbcategory["Article Teaser"]%></div>
    </div>
    <%
} 
%>

KBListingML.ascx.cs

using System;
using System.Collections.Generic;
using Sitecore.Data.Items;
using System.Linq;
using Sitecore.Web.UI.WebControls;
using Sitecore.Links;

namespace DigiconNew.layouts.Sublayouts.Controls
{
    public partial class KnowledgeBaseListing : System.Web.UI.UserControl
    {
        public List<Item> KBCategories = new List<Item>();

        protected void Page_Load(object sender, EventArgs e)
        {
            var item = DataSourceItem ?? Sitecore.Context.Item;

            string query = "/sitecore/content//*[@@templatename = 'Knowledgebase Article' AND contains (@Tags, '" + item.ID + "')]";
            Item[] itemsToShow = Sitecore.Context.Database.SelectItems(query); 

            KBCategories = itemsToShow.ToList();  
        }

        protected string DataSource
        {
            get { return ((Sublayout)this.Parent).DataSource; }
        }

        protected Item DataSourceItem
        {
            get { return Sitecore.Context.Database.GetItem(DataSource); }
        }

        public string GetURL(Item item)
        {
            return Sitecore.Links.LinkManager.GetItemUrl(item);
        }

    }
}