ASP.NET Application is displaying american date formats

Question

One of my development applications has today started displaying American formatted short dates where I am expecting British formatting.

The dates are being rend

Answer 1

The windows regional settings does not affect any website, unless the website is programmed to get the regional settings from the browser preferred languages and apply them to the ASP site

Use the globalization option in the web.config

<globalization culture="es-AR" uiCulture="es" />

OR

Set the value in the global.aspx Application_BeginRequest method

Sub Application_BeginRequest(ByVal sender As Object, ByVal e As EventArgs)
    Dim lang As String = "es"
    If HttpContext.Current.Request.Path.Contains("/en/") Then
        lang = "en"
    ElseIf HttpContext.Current.Request.Path.Contains("/pt/") Then
        lang = "pt"
    ElseIf HttpContext.Current.Request.Path.Contains("/es/") Then
        lang = "es"
    End If
    Thread.CurrentThread.CurrentUICulture = CultureInfo.GetCultureInfo(lang)
    Thread.CurrentThread.CurrentCulture = CultureInfo.CreateSpecificCulture(lang)
End Sub

Answer 2

From MSDN

The value of the current DateTime object is formatted using the pattern defined by the DateTimeFormatInfo.ShortDatePattern property associated with the current thread culture. The return value is identical to the value returned by specifying the "d" standard DateTime format string with the ToString(String) method.

Have you tried changing the culture for the current thread? This can be set on a per page basis as well - http://msdn.microsoft.com/en-us/library/bz9tc508%28v=vs.85%29.aspx.