Guid Structure

Represents a globally unique identifier (GUID).

Imports System.Runtime.InteropServices
' Guid for the interface IMyInterface.
<Guid("F9168C5E-CEB2-4faa-B6BF-329BF39FA1E4")> _
Interface IMyInterface
 Sub MyMethod()
End Interface
' Guid for the coclass MyTestClass.
<Guid("936DA01F-9ABD-4d9d-80C7-02AF85C822A8")> _
Public Class Example
 Implements IMyInterface
 Public Sub MyMethod() Implements IMyInterface.MyMethod
 End Sub
 Public Shared Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)
 Dim IMyInterfaceAttribute As Attribute = Attribute.GetCustomAttribute(GetType(IMyInterface), GetType(GuidAttribute))
 ' The Value property of GuidAttribute returns a string. 
 outputBlock.Text += String.Format("IMyInterface Attribute: " + CType(IMyInterfaceAttribute, GuidAttribute).Value) & vbCrLf
 ' Using the string to create a guid.
 Dim myGuid1 As New Guid(CType(IMyInterfaceAttribute, GuidAttribute).Value)
 ' Using a byte array to create a guid.
 Dim myGuid2 As New Guid(myGuid1.ToByteArray())
 ' Equals is overridden and so value comparison is done though references are different.
 If myGuid1.Equals(myGuid2) Then
 outputBlock.Text &= "myGuid1 equals myGuid2" & vbCrLf
 Else
 outputBlock.Text &= "myGuid1 not equals myGuid2" & vbCrLf
 End If
 ' Equality operator can also be used to determine if two guids have same value.
 If myGuid1.ToString() = myGuid2.ToString() Then
 outputBlock.Text &= "myGuid1 == myGuid2" & vbCrLf
 Else
 outputBlock.Text &= "myGuid1 != myGuid2" & vbCrLf
 End If
 End Sub
End Class
' The example displays the following output:
' IMyInterface Attribute: F9168C5E-CEB2-4faa-B6BF-329BF39FA1E4
' myGuid1 equals myGuid2
' myGuid1 == myGuid2

using System;
using System.Runtime.InteropServices;
// Guid for the interface IMyInterface.
[Guid("F9168C5E-CEB2-4faa-B6BF-329BF39FA1E4")]
interface IMyInterface
{
 void MyMethod();
}
// Guid for MyTestClass.
[Guid("936DA01F-9ABD-4d9d-80C7-02AF85C822A8")]
public class Example : IMyInterface
{
 public void MyMethod() { }
 public static void Demo(System.Windows.Controls.TextBlock outputBlock)
 {
 Attribute IMyInterfaceAttribute = Attribute.GetCustomAttribute(typeof(IMyInterface), typeof(GuidAttribute));
 // The Value property of GuidAttribute returns a string. 
 outputBlock.Text += "IMyInterface Attribute: " + ((GuidAttribute)IMyInterfaceAttribute).Value + "\n";
 // Using the string to create a guid.
 Guid myGuid1 = new Guid(((GuidAttribute)IMyInterfaceAttribute).Value);
 // Using a byte array to create a guid.
 Guid myGuid2 = new Guid(myGuid1.ToByteArray());
 // Equals is overridden and so value comparison is done though references are different.
 if (myGuid1.Equals(myGuid2))
 outputBlock.Text += "myGuid1 equals myGuid2" + "\n";
 else
 outputBlock.Text += "myGuid1 not equals myGuid2" + "\n";
 // Equality operator can also be used to determine if two guids have same value.
 if (myGuid1 == myGuid2)
 outputBlock.Text += "myGuid1 == myGuid2" + "\n";
 else
 outputBlock.Text += "myGuid1 != myGuid2" + "\n";
 }
}
// The example displays the following output:
// IMyInterface Attribute: F9168C5E-CEB2-4faa-B6BF-329BF39FA1E4
// myGuid1 equals myGuid2
// myGuid1 == myGuid2

System Namespace