Please help me create querystrings in the URLs for my languages! Complete codes included

Question

I somehow managed to make my company's website in 9 languages, using Visual Studio 2010 / VB / ASP.NET 4.0. I believe I'm using sessions. But you can tell for sure if you see the code provided below. I know this message is long, but I really need help.

It's a multilingual site, and I managed to put flags on the homepage. When I click a flag, the page's text changes to that language. When you click the French flag, it gets the information from the "FR" .resx resource file in my apps_GlobalResources folder. It stays on that language for the end-user's entire session. Great! Well, not so great.

The URL, for instance, about.aspx, remains about.aspx. Granted, the text changes to French, but I've been told that it's recommended to make it look like, if the client chooses French, for example, domain.com/about.aspx?lang=FR

But I have NO idea how to do this. If anybody can guide me clearly in the right direction, it'd be sincerely appreciated!!!

(For reference, if anybody is kind enough to delve into this issue, which may be a simple one, all of my files I've used in this are included below -- and they're kinda lengthy)

----Homepage.master (how I'm calling the languages -- just 2 samples)--

  <asp:LinkButton ID="LinkButton6" runat="server"
  CommandArgument="de" OnClick="RequestLanguageChange_Click"
  class="flagbutton">      
  <asp:Image ID="Image7" runat="server" ImageUrl="~/images/flagde.png"
  tooltip="View this website in Deutsch" title="View this website in Deutsch"/>
  <img class="map" src="images/flaghoverde.png" alt=""/>
  </asp:LinkButton>

  <asp:LinkButton ID="LinkButton5" runat="server"
  CommandArgument="fr" OnClick="RequestLanguageChange_Click"
  class="flagbutton">      
  <asp:Image ID="Image6" runat="server" ImageUrl="~/images/flagfr.png"
  tooltip="Voir ce site en français" title="Voir ce site en français"/>
  <img class="map" src="images/flaghoverfr.png" alt=""/>
  </asp:LinkButton>

---------------code behind homepage.master.vb---------------------

     Partial Public Class Homepage
    Inherits System.Web.UI.MasterPage
    Protected Sub Page_Load(sender As Object, e As EventArgs)
    End Sub

     Protected Sub RequestLanguageChange_Click(sender As Object, e As EventArgs)
    Dim senderLink As LinkButton = TryCast(sender, LinkButton)

    'store requested language as new culture in the session
    Session(Udev.MasterPageWithLocalization.Classes.Global.SESSION_KEY_CULTURE) = 
    senderLink.CommandArgument

    'reload last requested page with new culture
    Server.Transfer(Request.Path)
   End Sub
   End Class

---------------------BasePage.vb in App_Code folder--------------------

  Imports Microsoft.VisualBasic
  Imports System
  Imports System.Data
  Imports System.Configuration
  Imports System.Globalization
  Imports System.Threading
  Imports System.Web
  Imports System.Web.Security
  Imports System.Web.UI
  Imports System.Web.UI.WebControls
  Imports System.Web.UI.WebControls.WebParts
  Imports System.Web.UI.HtmlControls

  Namespace Udev.MasterPageWithLocalization.Classes
''' <summary>
''' Custom base page used for all web forms.
''' </summary>
Public Class BasePage
    Inherits Page
    Protected Overrides Sub InitializeCulture()
        'retrieve culture information from session
        Dim culture__1 As String =  
             Convert.ToString(Session([Global].SESSION_KEY_CULTURE))

        'check whether a culture is stored in the session
        If culture__1.Length > 0 Then
            Culture = culture__1
        End If

        'set culture to current thread
        Thread.CurrentThread.CurrentCulture =  
        CultureInfo.CreateSpecificCulture(culture__1)
        Thread.CurrentThread.CurrentUICulture = New CultureInfo(culture__1)

        'call base class
        MyBase.InitializeCulture()
    End Sub
   End Class
  End Namespace

----------------------Culture.vb in App_Code folder--------------------

  Imports Microsoft.VisualBasic
  Imports System
  Imports System.Data
  Imports System.Configuration
  Imports System.Web
  Imports System.Web.Security
  Imports System.Web.UI
  Imports System.Web.UI.WebControls
  Imports System.Web.UI.WebControls.WebParts
  Imports System.Web.UI.HtmlControls

  Namespace Udev.MasterPageWithLocalization.Classes
''' <summary>
''' This class provides ISO definitions for all cultures that are supported by this      
 application.
''' </summary>
Public Structure Culture
    'German - Switzerland definition
    Public Const DE As String = "de"
    'English - Great Britain definition
    Public Const EN As String = "en"
     End Structure
  End Namespace

------------------Global.vb in App_Code folder------------------------

  Imports System
  Imports System.Data
  Imports System.Configuration
  Imports System.Web
  Imports System.Web.Security
  Imports System.Web.UI
  Imports System.Web.UI.WebControls
  Imports System.Web.UI.WebControls.WebParts
  Imports System.Web.UI.HtmlControls

  Namespace Udev.MasterPageWithLocalization.Classes
''' <summary>
''' Summary description for Global
''' </summary>
Public Structure [Global]
    Public Const SESSION_KEY_CULTURE As String = "culture"
    End Structure
  End Namespace

Answer 1

Add something like this to your pages, at the top of OnInit (least preferred, as it means code-duplication). Ideally, this code would go to your base-page's oninit (preferred), or your master-pages's oninit (less preferred). Either way, it should work the way that you want.

if(this.Request.Querystring["lang"] == null)
{
    string path = this.Request.Url.AbsolutePath;
    string query = this.Request.Url.Query;
    if(query.length == 0)
        query = "?lang="; // concatenate language code here
    else
        query += "&lang="; // conc. lang. code here
    this.Response.Redirect(path + query, true);
    return;
}

This means: if the lang isn't in query, refresh the page, but this time with lang in query.

I hope I didn't misunderstand the question.

---

EDIT: VB version (oh, was it painful; I actually had to create a VB project for this):

Protected Overrides Sub OnInit(e As System.EventArgs)
    MyBase.OnInit(e)

    If Me.Request.QueryString("lang").Length = 0 Then
        Dim path As String = Me.Request.Url.AbsolutePath
        Dim query As String = Me.Request.Url.Query

        If query.Length = 0 Then
            query = "?lang=" ' + add lang here
        Else
            query += "&lang=" ' add lang
        End If

        Me.Response.Redirect(path + query, True)
        Return
    End If

End Sub

So, it looks like you don't have the OnOnit in your base class, but you can override it.