Localising date format descriptors

Question

What is the best way to localise a date format descriptor?

As anyone from a culture which does not use the mm/dd/yyyy format knows, it is annoying to have to enter dates in this format. The .NET framework provides some very good localisation support, so it's trivial to parse dates according to the users culture, but you often want to also display a helpful hint as to the format required (especially to distinguish between yy and yyyy which is interchangeable in most cultures).

What is the best way to do this in a way that make sense to most users (e.g. dd/M/yyy is confusing because of the change in case and the switching between one and two letters).

Answer 1

Here is my current method. Any suggestions?

Regex singleMToDoubleRegex = new Regex("(?<!m)m(?!m)");
Regex singleDToDoubleRegex = new Regex("(?<!d)d(?!d)");
CultureInfo currentCulture = CultureInfo.CurrentUICulture;

// If the culture is netural there is no date pattern to use, so use the default.
if (currentCulture.IsNeutralCulture)
{
    currentCulture = CultureInfo.InvariantCulture;
}

// Massage the format into a more general user friendly form.
string shortDatePattern = CultureInfo.CurrentUICulture.DateTimeFormat.ShortDatePattern.ToLower();
shortDatePattern = singleMToDoubleRegex.Replace(shortDatePattern, "mm");
shortDatePattern = singleDToDoubleRegex.Replace(shortDatePattern, "dd");