Date and Time Format Strings
DateTime format strings control formatting operations in which a date and/or time is represented as a string.
DateTime format strings fall into two categories:
Standard DateTime format strings consist of one standard DateTime format specifier. Each standard format specifier denotes a particular, commonly used string representation of a date and time.
Custom DateTime format strings consist of one or more custom numeric format specifiers. Combine custom DateTime format specifiers to define an application-specific pattern that determines how date and time data is formatted
DateTime format strings are supported by the ToString method of the composite formatting feature, which is used by certain Write and WriteLine methods of the and classes, the method, and the method.type. DateTime format strings are also supported by the .NET Framework