Guid.Empty 字段

定义

Guid 结构的只读实例,其值均为零。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 

字段值

注解

可以将 GUID 与 @no__t 字段的值进行比较,以确定 GUID 是否为非零值。You can compare a GUID with the value of the Guid.Empty field to determine whether a GUID is non-zero. 下面的示例使用 Equality 运算符比较两个 GUID 值与 Guid.Empty,以确定它们是否仅包含零。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

适用于