Convert a two digit year to a four digit year

Question

This is a question of best practices. I have a utility that takes in a two digit year as a string and I need to convert it to a four digit year as a string. right now I do <

Answer 1

Had a similar issue, and came up with this... HTH!

value = this.GetDate()

if (value.Length >= 6)//ensure that the date is mmddyy
{
    int year = 0;

    if (int.TryParse(value.Substring(4, 2), out year))
    {
        int pastMillenium = int.Parse(DateTime.Now.ToString("yyyy").Substring(0, 2)) - 1;

        if (year > int.Parse(DateTime.Now.ToString("yy")))//if its a future year it's most likely 19XX
        {
            value = string.Format("{0}{1}{2}", value.Substring(0, 4), pastMillenium, year.ToString().PadLeft(2, '0'));
        }
        else
        {
            value = string.Format("{0}{1}{2}", value.Substring(0, 4), pastMillenium + 1, year.ToString().PadLeft(2, '0'));
        }
    }
    else
    {
        value = string.Empty;
    }
}
else
{
    value = string.Empty;
}