Side By Side Assemblies

Side-by-side Assemblies



Side-by-side assemblies allow multiple versions of the same DLL to be loaded and available to the same application at the same time.



The SxS Manager is responsible for using the manifests of the application and the Side-by-side (SxS) assemblies.



Overview link: http://msdn.microsoft.com/en-us/library/aa376307.aspx









Isolated Applications



SxS is a part of an overall strategy to implement Isolated Applications.



Isolated Applications are important because they enable stable and reliable installations that are unaffected by installation or removal of other applications.



Isolated and SxS applications can also be reconfigured after deployment without re-installing.



Overview of Isolated Applications: http://msdn.microsoft.com/en-us/library/aa375190(VS.85).aspx











Manifests are the XML files that ship with SxS, Isolated, and other assemblies. They describe the assembly, and contain information for binding and activation.



Manifests: http://msdn.microsoft.com/en-us/library/aa375365(VS.85).aspx











To create a manifest you can include it in an actual DLL or .EXE, or you can include a standalone PE file that contains the assembly manifest information.



http://msdn.microsoft.com/en-us/library/1w45z383.aspx





How the runtime locates assemblies: http://msdn.microsoft.com/en-us/library/yx7xezcf.aspx

And related best practices for assembly loading: http://msdn.microsoft.com/en-us/library/dd153782.aspx

Installing multiple versions of the same ClickOnce application

While researching Side-by-side (SxS) assemblies and ClickOnce I found this article by Brian Noyes that addresses the problem with attempting to install two versions of a ClickOnce application.



http://briannoyes.net/CommentView,guid,fe63caf8-a84e-4cb4-a784-703835ac327e.aspx





Essentially he says that the Application Identity is the actual discriminator that allows two versions of the same ClickOnce application to be installed on the same machine. Visual Studio set's the application id when publishing, but you can use the mageui.exe, or some other manifest manager tool, to change the application id.