IT:AD:ASP.NET:Win Forms:HowTo:Set the Current Culture

(UP)
- IT:AD:ASP.NET:Win Forms:HowTo:Set the Current Culture

Summary

.NET applications work with two Cultures:

CurrentCulture: controls formatting of numbers, dates, currency.
CurrentUICulture: defines what strings are used.

Thread.CurrentThread.CurrentCulture = new CultureInfo("en-US");
Thread.CurrentThread.CurrentUICulture = new CultureInfo("en-US");

Most browsers attach a header defining what language they prefer receiving resources in:

Accept-Language:en-NZ,de;q=0.8,en-US;q=0.6,en;q=0.4

In an ASP.NET application, the information encoded in the Accept-Language headers can be automatically used to set the current culture on the server side, or falling back to a default (in this case 'en-NZ') using settings in web.config similar to the following:

<configuration>
  <system.web>
    <globalization culture="auto:en-NZ" uiCulture="auto:en-NZ" />
  </system.web>
</configuration>

Note that the culture is switched very early in the ASP.NET HttpApplication lifecycle, already available in the Application_BeginRequest (even before Session and Page events).

If you ever need to you can retrieve the currently set language using:

culture = CultureInfo.InstalledUICulture.IetfLanguageTag;

if (HttpContext.Current != null && HttpContext.Current.Request.UserLanguages != null)
{
    culture = Request.UserLanguages[0];     
}

The automatic feature of ASP.NET is handy.

But one should go further – allowing users to define their own language from a Profile setting.

Application_BeginRequest is a tempting place to do this – but it's only useful when using Cookies, as it happens prior to Application_AuthenticateRequest, which is where the thread's user gets set by an HttpHandler.

a production site should allow user customisation, in which case a Profile will be needed.
a production site will probably end up requiring more than one personal setting. As it's inappropriate to round-trip unnecessarily a cookie for each setting, better to deal with this upcoming reality right from the start. </callout>

protected void Application_BeginRequest()
{
   //Don't set your user's preferred Cultures here:
}
protected void Application_AuthenticateRequest(object sender, EventArgs e)
{
    if (HttpContext.Current.User != null)
    {
        //Thread Identity is set -- use it to get an App User
        User u = Helpers.User().SelectByUsername(HttpContext.Current.User.Name, false);
                
        System.Threading.CurrentCulture = user.Culture;
        System.Threading.CurrentUICulture = user.Culture;
    }
    //If anon user, this could be done by cookies?
}

### ASP.NET WebForms ###

The above works for ASP.NET in general. If for any reason you are still using WinForms (why?!?) you need to override the InitializeCulture method¹⁾:

<%@ Page Language="C#" uiculture="auto" %>
<%@ Import Namespace="System.Threading" %>
<%@ Import Namespace="System.Globalization" %>
<script runat="server">
protected override void InitializeCulture()
{
    if (Request.Form["ctl00$ctl00$ DropDownListMaster "] != null)
    {
        //Read control on Master page:
        string selectedLanguage = Request.Form["ctl00$ctl00$DropDownListMaster"];
        //Persist value in Response cookie:
        Response.Cookies["CurrentCulture"].Value = selectedLanguage;
        //Or persist it in the Users profile
        //TODO:....
    }
    else if (Request.Cookies["CurrentCulture"] != null)
    {
        selectedLanguage = Request.Cookies["CurrentCulture"].Value;
    }
        //Then set the cultureCode:
    if (!selectedLanguage.IsNullOrEmpty()){
        Thread.CurrentThread.CurrentCulture = CultureInfo.CreateSpecificCulture(selectedLanguage);
        Thread.CurrentThread.CurrentUICulture = new CultureInfo(selectedLanguage);
    }
    base.InitializeCulture();
}
</script>
<html>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:ListBox ID="ListBox1" runat="server">
            <asp:ListItem Value="en-US" Selected="True">English</asp:ListItem>
            <asp:ListItem Value="es-MX">Español</asp:ListItem>
            <asp:ListItem Value="de-DE">Deutsch</asp:ListItem>
        </asp:ListBox><br />
        <asp:Button ID="Button1" runat="server" Text="Set Language" meta:resourcekey="Button1" />
        <br />
        <asp:Label ID="Label1" runat="server" Text="" meta:resourcekey="Label1" />
        </div>
    </form>
</body>
</html>

###

<callout icon=“true” type=“tip”

>

T

hat said, know that Async requests, in a self-hosted environment, can cause issues ²⁾. They remain fine when hosted in IIS though.