Check out TryParseExact.
public static string FormatDate(string input, string goalFormat, string[] formats)
{
var c = CultureInfo.CurrentCulture;
var s = DateTimeStyles.None;
var result = default(DateTime);
if (DateTime.TryParseExact(input, formats, c, s, out result))
return result.ToString(goalFormat);
throw new FormatException("Unhandled input format: " + input);
}
Example Usage
var formats - new[] { "dd/MM/yy", "dd/MM/yyyy" };
var next = csvReader.Get("DateField");
var formattedDate = FormatDate(next, "dd/MM/yyyy", formats);