Bear in mind that a DateTime should generally be stored in Universal format and converted to local format when be displayed in a GUI or used in a report. This handy extension for date time format strings saves having to remember their obscure format codes or look them up every time.
// See here for more info
// https://docs.microsoft.com/en-us/dotnet/standard/base-types/standard-date-and-time-format-strings
public static class DateTimeToStringExtender
{
public static bool ParseGeneralShortDateTime(this string dateTimeStr, out DateTime dateTime)
{
var format = "g"; // Standard short date time format: "dd/MM/yyyy HH:mm:ss" for UK
bool result = false;
CultureInfo provider = CultureInfo.CurrentCulture;
result = DateTime.TryParseExact(dateTimeStr.Trim(), format, provider, DateTimeStyles.None, out dateTime);
return result;
}
/// <summary>
/// Convert a DateTime to a YearMonthDay string of the form yyyy/MM/dd
/// </summary>
/// <param name="dt">target</param>
/// <returns>YearMonthDay string of the form yyyyMMdd</returns>
public static string ToYyyyMmDdString(this DateTime dt, char separator = char.MinValue)
{
string format = "yyyyMMdd";
if (!char.IsControl(separator))
{
format = "yyyy" + separator + "MM" + separator + "dd";
}
var res = dt.ToString(format);
return res;
}
/// <summary>
/// Convert a DateTime to a YearMonthDay string of the form DdMmYyyy
/// </summary>
/// <param name="dt">target</param>
/// <returns>YearMonthDay string of the form DdMmYyyy</returns>
public static string ToDdMmYyyyString(this DateTime dt, char separator = char.MinValue)
{
string format = "ddMMyyyy";
if (!char.IsControl(separator))
{
format = "dd" + separator + "MM" + separator + "yyyy";
}
return dt.ToString(format);
}
/// <summary>
/// Convert a DateTime to a YearMonthDay string of the form yyyyMMdd_HHmmss where the hour is in the 24 hour format
/// </summary>
/// <param name="dt">target</param>
/// <returns>YearMonthDay string of the form yyyyMMdd_HHmmss</returns>
public static string ToYyyyMmDd_HhMmSsString(this DateTime dt)
{
return dt.ToString("yyyyMMdd_HHmmss");
}
/// <summary>
/// Convert a DateTime to a YearMonthDay string of the form yyyyMMdd_HHmmss_ffffff where the hour is in the 24 hour format
/// Useful for creating randomised filenames based upon the date
/// </summary>
/// <param name="dt">target</param>
/// <returns>YearMonthDay string of the form yyyyMMdd_HHmmss_ffffff</returns>
public static string To_YyyyMmDd_HhMmSs_ffffff(this DateTime dt)
{
return dt.ToString("yyyyMMdd_HHmmss_ffffff");
}
/// <summary>
/// Convert a DateTime to a YearMonthDay string of the form yyyyMMdd_HHmmss where the hour is in the 24 hour format
/// </summary>
/// <param name="dt">target</param>
/// <returns>YearMonthDay string of the form yyyyMMdd_HHmmss</returns>
public static string ToYyyyMmDd_HhMmSsString(this DateTime dt, char dateSeparator = char.MinValue, char timeSeparator = char.MinValue)
{
string format = "yyyyMMdd_HHmmss";
if (!char.IsLetterOrDigit(dateSeparator) && !char.IsControl(dateSeparator))
{
format = "yyyy" + dateSeparator + "MM" + dateSeparator + "dd" + "_" + "HH" + timeSeparator + "mm" + timeSeparator + "ss";
}
return dt.ToString(format);
}
/// <summary>
/// Emits a date time (culture independent) string of the form
/// "ddd, dd MMM yyyy HH':'mm':'ss 'GMT'"
/// (eg.: "Sun, 09 Mar 2008 16:05:07 GMT").
/// Works on universal date times only
/// </summary>
/// <param name="dateTime">target date time to convert to a string</param>
/// <returns>dateTime formatted as a string</returns>
public static string ToRfc1123FormatString(this DateTime dateTime)
{
string result = dateTime.ToUniversalTime().ToString("r");
return result;
}
/// <summary>
/// Convert a DateTime to a string of the form "2008-03-09 16:05:07Z"
/// where the '-' character is culture dependant
/// </summary>
/// <param name="dt">target</param>
/// <returns>string of the form "2008-03-09 16:05:07Z" where '-' character is culture dependant</returns>
public static string ToUniversalSortableString(this DateTime dt)
{
return dt.ToUniversalTime().ToString("u");
}
// 2009-06-15T13:45:30 --> Monday, June 15, 2009 8:45:30 PM (for en-US)
public static string ToUniversalFull(this DateTime dateTime)
{
var res = dateTime.ToUniversalTime().ToString("U");
return res;
}
/// <summary>
/// Emits a sortable date time (culture independent) string of the form "yyyy'-'MM'-'dd'T'HH':'mm':'ss" (eg.: "2008-03-09T16:05:07"")
/// </summary>
/// <param name="dateTime">target date time to convert to a string</param>
/// <returns>dateTime formatted as a string</returns>
public static string ToSortableFormatString(this DateTime dateTime)
{
string result = dateTime.ToString("s");
return result;
}
/// <summary>
/// Emits a result date time format string using a pattern that preserves
/// time zone information and emits a result string that complies with
/// ISO 8601 ("yyyy'-'MM'-'dd'T'HH':'mm':'ss'.'fffffffK"), preserves
/// the DateTime kind.
/// </summary>
/// <param name="dateTime">target date time to convert to a string</param>
/// <returns>dateTime formatted as a string</returns>
// 2009-06-15T13:45:30 (DateTimeKind.Utc) -->; 2009-06-15T13:45:30.0000000Z
// 2009-06-15T13:45:30 (DateTimeKind.Local) --> 2009-06-15T13:45:30.0000000-07:00 (depending on the time zone)
// 2009-06-15T13:45:30 (DateTimeKind.Unspecified) --> 2009-06-15T13:45:30.0000000
public static string ToRoundTripFormatString(this DateTime dateTime)
{
string result = dateTime.ToString("o");
return result;
}
static readonly string[] formats = {
// Extended formats
"o",
"yyyy-MM-ddTHH:mm:ss.ffffffZ",
"yyyy-MM-ddTHH:mm:ss.fffffZ",
"yyyy-MM-ddTHH:mm:ss.ffffZ",
"yyyy-MM-ddTHH:mm:ss.fffZ",
"yyyy-MM-ddTHH:mm:ss.ffZ",
"yyyy-MM-ddTHH:mm:ss.fZ",
"yyyy-MM-ddTHH:mm:ssZ"
};
public static DateTime ParseToIso8601DateTime(this string str)
{
return DateTime.ParseExact(str, formats,
CultureInfo.InvariantCulture, DateTimeStyles.RoundtripKind);
}
}
