Guid.Empty 欄位

定義

Guid 結構的唯讀執行個體,其值全為零。A read-only instance of the Guid structure whose value is all zeros.

public: static initonly Guid Empty;
public static readonly Guid Empty;
 staticval mutable Empty : Guid
Public Shared ReadOnly Empty As Guid 

欄位值

Guid

備註

您可以比較 GUID 與 [Guid.Empty] 欄位的值,以判斷 GUID 是否為非零。You can compare a GUID with the value of the Guid.Empty field to determine whether a GUID is non-zero. 下列範例會使用 Equality 運算子來比較兩個 GUID 值與 Guid.Empty,以判斷它們是否只包含零。The following example uses the Equality operator to compare two GUID values with Guid.Empty to determine whether they consist exclusively of zeros.

// 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
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

適用於