Change Language Sharepoint using Drop Down List

Question

I'm trying to change the Sharepoint 2010 Language using a drop down list on a web part with the values. It work's fine but only change the language in the current page, not in all site. Here's the code:

using System;
using System.Threading;
using System.Globalization;
using System.Runtime.InteropServices;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Serialization;
using System.ComponentModel;
using Microsoft.SharePoint;
using Microsoft.SharePoint.WebControls;
using Microsoft.SharePoint.WebPartPages;
using Microsoft.SharePoint.Utilities;

namespace Contoso.Intranet.WebTemplates.SPSITEtestwebpart
{
    [ToolboxItemAttribute(false)]
    public class SPSITEtestwebpart : System.Web.UI.WebControls.WebParts.WebPart
    {
        DropDownList ddlIdioma;
        protected override void CreateChildControls()
        {
            ddlIdioma = new DropDownList();
            ddlIdioma.AutoPostBack = true;
            ddlIdioma.ID = "ddlIdioma";
            ddlIdioma.Items.Add("Seleccione Idioma...");
            ddlIdioma.Items.Add("Español");
            ddlIdioma.Items.Add("Ingles");
            ddlIdioma.DataBind();
            this.Controls.Add(ddlIdioma);
            ddlIdioma.SelectedIndexChanged += new EventHandler(ddlIdioma_SelectedIndexChanged);
        }

        protected void ddlIdioma_SelectedIndexChanged(object sender, EventArgs e)
        {
            Lenguaje();
        }      

        protected void Lenguaje()
        {
            SPSecurity.RunWithElevatedPrivileges(delegate()
            {
                using (SPSite site = new SPSite("http://alejandroa-pc/sites/publishing"))
                {
                    foreach (SPWeb web in site.AllWebs)
                    {
                        web.AllowUnsafeUpdates = true;
                        if (Page.IsPostBack)
                        {
                            if (ddlIdioma.SelectedValue.ToString() == "Español")
                            {
                                int idioma = 3082;
                                Thread.CurrentThread.CurrentCulture = new CultureInfo(idioma);
                                Thread.CurrentThread.CurrentUICulture = new CultureInfo(idioma);
                            }
                            else if (ddlIdioma.SelectedValue.ToString() == "Ingles")
                            {
                                int idioma = 1033;
                                Thread.CurrentThread.CurrentCulture = new CultureInfo(idioma);
                                Thread.CurrentThread.CurrentUICulture = new CultureInfo(idioma);
                            }
                            else
                            {
                                int idioma = 1033;
                                Thread.CurrentThread.CurrentCulture = new CultureInfo(idioma);
                                Thread.CurrentThread.CurrentUICulture = new CultureInfo(idioma);
                            }
                        }
                    }
                }
            });
        }

    }
}

Answer 1

The display language per user is stored in a cookie which you set like this:

<script type ="text/javascript"> 
// <![CDATA[
function OnSelectionChange(value)
{
    var today = new Date();
    var oneYear = new Date(today.getTime() + 365 * 24 * 60 * 60 * 1000);
    var url = window.location.href;
    document.cookie = "lcid=" + value + ";path=/;expires=" + oneYear.toGMTString();
    window.location.href = url;
}
// ]]>
</script>

See Understanding the Multilingual User Interface (MUI)