SharePoint 2010 populate DataGrid with list items error

[Maureen]

I am trying to create a User Control to place into a Telerik MegaMenu (RadMenu). The User Control is named "clientfilter" which will pull a sub-set of data from a SharePoint 2010 list. I have placed the following code into the "Page_Load" event but am getting errors on render.

protected void Page_Load(object sender, EventArgs e)
        {
            SPSite site = new SPSite("http://abcdev");
            using (SPWeb web = site.OpenWeb())
            {
                try
                {
                    SPList clientlist = web.Lists.TryGetList("clientmatter");
                    if (clientlist != null)
                    {
                        SPListItemCollection clientitems = clientlist.Items;
                        DataGrid dg = new DataGrid();
                        dg.DataSource = clientlist.Items.GetDataTable();

                        foreach (SPListItem clientitem in clientitems)
                        {
                            string clientddlvalue = clientitem["clientid"].ToString();
                            //myselect.Items.Add(clientddlvalue);

                        }

                        if ( !IsPostBack )
                         {
                           GridBoundColumn boundColumn;

                           //Important: first Add column to the collection
                           boundColumn = new GridBoundColumn();
                           this.RadGrid1.MasterTableView.Columns.Add(boundColumn);

                           //Then set properties
                           boundColumn.DataField = "clientid";
                           boundColumn.HeaderText = "clientid";
                         }
                    }
                }
                catch
                {

                }
                {
                    web.Dispose();
                }
            }

        }

The error I can see is "failure loading assembly 'Telerik.Web.UI.Design' ...", however, not sure if this is the real error or a by-product of a different error. When I originally entered the assembly registrations I mis-typed the name, however, I have subsequently fixed the name, but the error still persists. I have added the following to the GAC already:

• Telerik.Web.UI
• Telerik.Web.Design
• Telerik.Web.UI.Skins

In my custom master page I have the following registrations:

<%@ Register Tagprefix="telerik" Namespace="Telerik.Web.UI" Assembly="Telerik.Web.UI, Version=2012.3.1205.35, Culture=neutral, PublicKeyToken=121fae78165ba3d4" %>
<%@ Register Tagprefix="telerik" Namespace="Telerik.Web.Design" Assembly="Telerik.Web.Design, Version=2012.3.1205.35, Culture=neutral, PublicKeyToken=121fae78165ba3d4" %>

What am I missing? Why will the code not work?

Thank you in advance.

[Marin]

Hello,

 You can make sure that you are referencing the same version of the assemblies everywhere in the application and also that the assemblies are added to the SafeControls collection in the web.config file. For more information can refer to this help topic.
Additionally for databinding RadGrid we recommend using the NeedDataSource event.

All the best,
Marin
the Telerik team