Guid.Empty Field (System)

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.NET Framework Class Library for Silverlight
Guid.Empty Field

A read-only instance of the Guid class whose value is guaranteed to be all zeroes.

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)
Syntax

Visual Basic (Declaration)
Public Shared ReadOnly Empty As Guid
C#
public static readonly Guid Empty
Remarks

You can compare a GUID with the value of the Guid.Empty field to determine whether a GUID is non-zero. The following example uses the Equality operator to compare two GUID values with Guid.Empty to determine whether they consist exclusively of zeros.

Visual Basic

Module Example
   Public Sub Demo(outputBlock As System.Windows.Controls.TextBlock)
      ' Create a GUID and determine whether it consists of all zeros.
      Dim guid1 As Guid = Guid.NewGuid
      outputBlock.Text += guid1.ToString() + vbCrLf
      outputBlock.Text += String.Format("Empty: {0}", guid1 = Guid.Empty) + vbCrLf
      outputBlock.Text += vbCrLf

      ' Create a GUID with all zeros and compare it to Empty.
      Dim bytes(15) As Byte
      Dim guid2 As New Guid(bytes)
      outputBlock.Text += guid2.ToString() + vbCrLf
      outputBlock.Text += String.Format("Empty: {0}", guid2 = Guid.Empty) + vbCrLf
   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


C#

using System;

public class Example
{
   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      // Create a GUID and determine whether it consists of all zeros.
      Guid guid1 = Guid.NewGuid();
      outputBlock.Text += guid1.ToString() + "\n";
      outputBlock.Text += String.Format("Empty: {0}\n\n", guid1 == Guid.Empty);

      // Create a GUID with all zeros and compare it to Empty.
      Byte[] bytes = new Byte[16];
      Guid guid2 = new Guid(bytes);
      outputBlock.Text += guid2.ToString() + "\n";
      outputBlock.Text += String.Format("Empty: {0}\n", guid2 == Guid.Empty);
   }
}
// The example displays output like the following:
//       11c43ee8-b9d3-4e51-b73f-bd9dda66e29c
//       Empty: False
//       
//       00000000-0000-0000-0000-000000000000
//       Empty: True


Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0
Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

See Also

Reference