Guid struct represents a globally unique identifier: a 16-byte value.
Guids are often used for keys of various applications and databases.
The static Guid.NewGuid method generates a unique Guid:
Guid g = Guid.NewGuid (); Console.WriteLine (g.ToString());
To instantiate an existing value, use one of the constructors. The two most useful constructors are:
public Guid (byte[] b); // Accepts a 16-byte array public Guid (string g); // Accepts a formatted string
When represented as a string, a Guid is formatted as a 32-digit hexadecimal number, with optional hyphens after the 8th, 12th, 16th, and 20th digits.
The whole string can be optionally wrapped in brackets or braces:
Guid g1 = new Guid ("{0d57619c-1d6e-1847-17cb-1e2fc25081fe}"); Guid g2 = new Guid ("0d57619c1d6e184717cb1e2fc25081fe"); Console.WriteLine (g1 == g2); // True
ToByteArray method converts a Guid to a byte array.
static Guid.Empty property returns an empty Guid with all zeros, which is used in place of null.
using System; class MainClass//from w ww . j av a 2 s .com { public static void Main(string[] args) { Guid g = Guid.NewGuid (); Console.WriteLine (g.ToString()); } }