Use a Version object to store and compare the version number of an assembly. Note that you or an application can set a Version object to the version number of an assembly. However, a Version object is not automatically set to the version number of any particular assembly, and the Version class has no members that can acquire such information.

Version numbers consist of two to four components: major, minor, build, and revision. The major and minor components are required; the build and revision components are optional, but the build component is required if the revision component is defined. All defined components must be integers greater than or equal to 0. The format of the version number is as follows. Optional components are shown in square brackets ('[' and ']'):

major.minor[.build[.revision]]

The components are used by convention as follows:

• Major : Assemblies with the same name but different major versions are not interchangeable. This would be appropriate, for example, for a major rewrite of a product where backward compatibility cannot be assumed.

• Minor : If the name and major number on two assemblies are the same, but the minor number is different, this indicates significant enhancement with the intention of backward compatibility. This would be appropriate, for example, on a point release of a product or a fully backward compatible new version of a product.

• Build : A difference in build number represents a recompilation of the same source. This would be appropriate because of processor, platform, or compiler changes.

• Revision : Assemblies with the same name, major, and minor version numbers but different revisions are intended to be fully interchangeable. This would be appropriate to fix a security hole in a previously released assembly.

Subsequent versions of an assembly that differ only by build or revision numbers are considered to be Hotfix updates of the prior version.

Starting with .NET Framework 2.0, the MajorRevision and MinorRevision properties enable you to identify a temporary version of your application that, for example, corrects a problem until you can release a permanent solution. Furthermore, the Windows NT operating system uses the MajorRevision property to encode the service pack number.

This class implements the ICloneable, IComparable, IComparable<(Of <(T>)>), and IEquatable<(Of <(T>)>) interfaces.

Assigning Version Information to Assemblies

Retrieving Version Information

The following code example uses the Assembly class to obtain the Version object that identifies an assembly.

' This code example demonstrates the Version class.
' 
'   This code example loads an assembly and retrieves its 
'   version number. 
'   Typically, you would use code similar to this example 
'   to load a separate assembly and obtain its version number. 
'   However, solely to avoid using another assembly, this code 
'   example loads itself and retrieves its own version number. 
'
'   This code example is created in two steps:
'1) The AssemblyVersionAttribute attribute is applied to this 
'   code example at the assembly level. Then the code example 
'   is compiled into the MyAssembly.exe executable assembly.
'2) When MyAssembly.exe is executed, it loads itself, then 
'   displays its own version number. 

Imports System
Imports System.Reflection

' Apply the version number, 1.2.3.4, to this assembly.
<assembly:AssemblyVersionAttribute("1.2.3.4")>
Class Sample
    Public Shared Sub Main() 

' Use the Assembly class to load MyAssembly.exe. Note that
' the name of the assembly does not include the ".exe" suffix
' of the executable file.
        Dim myAsm As Assembly = Assembly.Load("MyAssembly")
        Dim aName As AssemblyName = myAsm.GetName()

' Store the version number in a Version object.
        Dim ver As Version = aName.Version

' Display the version number of MyAssembly.
        Console.WriteLine(ver)
    End Sub 'Main
End Class 'Sample

'This code example produces the following results:
'
'1.2.3.4
'

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

.NET Framework

.NET Compact Framework

XNA Framework

Reference