Guid.Empty Champ

Définition

Espace de noms:

System

Assembly:

System.Runtime.dll

Source:

Guid.cs

Instance en lecture seule de la structure Guid dont la valeur ne peut être composée que de zéros.

public: static initonly Guid Empty;

public static readonly Guid Empty;

 staticval mutable Empty : Guid

Public Shared ReadOnly Empty As Guid 

Valeur de champ

Guid

Remarques

Vous pouvez comparer un GUID à la valeur du Guid.Empty champ pour déterminer si un GUID est différent de zéro. L’exemple suivant utilise l’opérateur Equality pour comparer deux valeurs GUID avec Guid.Empty afin de déterminer si elles se composent exclusivement de zéros.

// Create a GUID and determine whether it consists of all zeros.
Guid guid1 = Guid.NewGuid();
Console.WriteLine(guid1);
Console.WriteLine($"Empty: {guid1 == Guid.Empty}\n");

// Create a GUID with all zeros and compare it to Empty.
var bytes = new Byte[16];
var guid2 = new Guid(bytes);
Console.WriteLine(guid2);
Console.WriteLine($"Empty: {guid2 == Guid.Empty}");

// The example displays output like the following:
//       11c43ee8-b9d3-4e51-b73f-bd9dda66e29c
//       Empty: False
//
//       00000000-0000-0000-0000-000000000000
//       Empty: True

open System

// Create a GUID and determine whether it consists of all zeros.
let guid1 = Guid.NewGuid()
printfn $"{guid1}"
printfn $"Empty: {guid1 = Guid.Empty}\n"

// Create a GUID with all zeros and compare it to Empty.
let bytes = Array.zeroCreate<byte> 16
let guid2 = Guid bytes
printfn $"{guid2}"
printfn $"Empty: {guid2 = Guid.Empty}"

// The example displays output like the following:
//       11c43ee8-b9d3-4e51-b73f-bd9dda66e29c
//       Empty: False
//
//       00000000-0000-0000-0000-000000000000
//       Empty: True

Module Example
   Public Sub Main()
      ' Create a GUID and determine whether it consists of all zeros.
      Dim guid1 As Guid = Guid.NewGuid
      Console.WriteLine(guid1)
      Console.WriteLine("Empty: {0}", guid1 = Guid.Empty)
      Console.WriteLine()
      
      ' Create a GUID with all zeros and compare it to Empty.
      Dim bytes(15) As Byte
      Dim guid2 As New Guid(bytes)
      Console.WriteLine(guid2)
      Console.WriteLine("Empty: {0}", guid2 = Guid.Empty)
   End Sub
End Module
' The example displays output like the following:
'       11c43ee8-b9d3-4e51-b73f-bd9dda66e29c
'       Empty: False
'       
'       00000000-0000-0000-0000-000000000000
'       Empty: True