C# - DateTime in besser lesbaren String umwandeln

public static class Extensions
{
    /// <summary>
    /// Converts to friendly date string.
    /// </summary>
    /// <param name="dateTime">The date time.</param>
    /// <returns></returns>
    public static string ToFriendlyDateString(this DateTime dateTime)
    {
        var dateString = string.Empty;
        if (dateTime.Date == DateTime.Today)
        {
            dateString = "Heute";
        }
        else if (dateTime.Date == DateTime.Today.AddDays(-1))
        {
            dateString = "Gestern";
        }
        else
        {
            dateString = dateTime.ToShortDateString();
        }
        return dateString += ",  " + dateTime.ToShortTimeString() + " Uhr";
    }
}