/// <summary>
/// <para>Specifies a custom format to use.</para>
/// <para>See https://docs.microsoft.com/en-us/dotnet/standard/base-types/custom-date-and-time-format-strings for more details.</para>
/// </summary>
/// <param name="format">Custom format string to use.</param>
public DateTimeFormatAttribute(string format)
{
if (string.IsNullOrWhiteSpace(format))
{
throw new ArgumentNullException(nameof(format), "Specified format cannot be null or empty.");
}
this.Kind = DateTimeFormatKind.Custom;
this.Format = format;
}
/// <summary>
/// Specifies a predefined format to use.
/// </summary>
/// <param name="kind">Predefined format kind to use.</param>
public DateTimeFormatAttribute(DateTimeFormatKind kind)
{
if (kind < 0 || kind > DateTimeFormatKind.InvariantLocaleShort)
{
throw new ArgumentOutOfRangeException(nameof(kind), "Specified format kind is not legal or supported.");
}
this.Kind = kind;
this.Format = null;
}
/// <summary>
/// Gets the format string associated with a specified <see cref="DateTimeFormatKind"/>.
/// </summary>
/// <param name="formatKind">The format kind.</param>
/// <returns>
/// The format string associated with a specified <see cref="DateTimeFormatKind"/>.
/// </returns>
public static string ToFormatString(
this DateTimeFormatKind formatKind)
{
if (formatKind == DateTimeFormatKind.Unknown)
{
throw new ArgumentOutOfRangeException(nameof(formatKind), Invariant($"{nameof(formatKind)} is {nameof(DateTimeFormatKind)}.{nameof(DateTimeFormatKind.Unknown)}"));
}
if (!DateTimeFormatKindToFormatStringMap.ContainsKey(formatKind))
{
throw new NotSupportedException(Invariant($"This {nameof(DateTimeFormatKind)} is not supported: {formatKind}."));
}
var result = DateTimeFormatKindToFormatStringMap[formatKind];
return(result);
}
/// <summary>
/// Converts the value of the current <see cref="DateTime"/> object to its equivalent
/// string representation using the specified format and culture-specific format information.
/// </summary>
/// <param name="value">The value.</param>
/// <param name="formatKind">The kind of formatting to apply.</param>
/// <param name="cultureKind">OPTIONAL kind of culture to use. DEFAULT is to use the invariant culture.</param>
/// <returns>
/// A string representation of the specified <see cref="DateTime"/> value as specified by format and culture.
/// </returns>
public static string ToString(
this DateTime value,
DateTimeFormatKind formatKind,
CultureKind cultureKind = CultureKind.Invariant)
{
if (formatKind == DateTimeFormatKind.Unknown)
{
throw new ArgumentOutOfRangeException(nameof(formatKind), Invariant($"{nameof(formatKind)} is {nameof(DateTimeFormatKind)}.{nameof(DateTimeFormatKind.Unknown)}"));
}
if (cultureKind == CultureKind.Unknown)
{
throw new ArgumentOutOfRangeException(nameof(cultureKind), Invariant($"{nameof(cultureKind)} is {nameof(CultureKind)}.{nameof(CultureKind.Unknown)}"));
}
var formatString = formatKind.ToFormatString();
var cultureInfo = cultureKind.ToCultureInfo();
var result = value.ToString(formatString, cultureInfo);
return(result);
}