To switch language in your ASP.NET application, you have to set the Thread.CurrentUICulture-Property.
Sample
protected void setLang_Click(object sender, EventArgs e)
{ LinkButton btn = sender as LinkButton;
if (btn != null)
{ Thread.CurrentThread.CurrentUICulture = System.Globalization.CultureInfo.GetCultureInfo(btn.CommandArgument);
}
}
If the language resource file can be found, the localized text will be displayed.