Choosing Between Shared and Versioned VSPackages
Different versions of Visual Studio can coexist on the same computer. VSPackages can support any mix of Visual Studio versions.
You can enable side-by-side installations of VSPackages through either of two strategies, the shared strategy or the versioned strategy. Both accommodate the presence of multiple versions of Visual Studio and associated versions of the .NET Framework.
In the shared strategy, one VSPackage is registered for use in multiple versions of Visual Studio. In the versioned strategy, multiple VSPackage DLLs are installed, one for each version of Visual Studio that you support.
Shared VSPackages
Using a shared VSPackage is appropriate when you use the same VSPackage in multiple versions of Visual Studio. To implement a shared VSPackage, you must take the following steps:
Make your VSPackage compatible with multiple versions of Visual Studio. Two ways of doing so are available:
Limit your VSPackage to using only the features of the earliest version of Visual Studio that you support.
Program your VSPackage to adapt to the version of Visual Studio in which it is running. Then, if queries for newer services fail, your VSPackage can offer other services that are supported in older versions of Visual Studio.
Register your VSPackage appropriately. For more information, see VSPackage Registration and Managed VSPackage Registration.
Register file extensions appropriately. For more information, see Registering File Name Extensions for Side-By-Side Deployments.
Create an installer that deploys your VSPackage for the appropriate versions of Visual Studio. For more information, see Installing VSPackages With Windows Installer and Component Management.
Address the issue of registration collisions. For more information, see VSPackage Registration.
Ensure that both shared and versioned files respect reference counting to allow safe installation and removal of multiple versions. For more information, see Component Management.
Versioned VSPackages
Under the versioned VSPackage strategy, you create one VSPackage for each version of Visual Studio that you support. Doing this is appropriate when you expect to take advantage of services provided by later versions of Visual Studio, because each VSPackage can evolve without affecting the others. Nevertheless, the versioned strategy of creating multiple binaries, either from a single code base or from multiple independent code bases, might entail more initial development than the shared strategy. Also, additional setup work might be required because you must create either a separate setup for each version or a single setup that detects the versions of Visual Studio that are installed and that your VSPackage supports.
Binary Compatibility
Generally, binary compatibility enables native-code VSPackages developed with earlier versions of Visual Studio to run in later versions of Visual Studio. However, there are three important exceptions:
If your VSPackage relies on a particular version of the common language runtime, then it must determine in which version of Visual Studio it is running.
A VSPackage might have a dependency on a specific feature of another VSPackage or another product. Consequently, the VSPackage can run only where the dependency is satisfied.
A VSPackage might be affected by a security fix in a Visual Studio service pack or a later version of Visual Studio. In those cases, a VSPackage developed with an earlier version of the Visual Studio SDK might not run in versions of Visual Studio after the security fix was applied. However, you can rebuild your package with the later version and have it also run in earlier versions.
Managed VSPackages must be built using a version of Visual Studio and the Visual Studio SDK that match the target version of Visual Studio.
In addition to planning for binary compatibility for your VSPackage binaries, you also should consider solution and project file formats. If your VSPackage creates a new project type, you must decide whether it can run in just one version or in multiple versions of Visual Studio. For more information, see How to: Upgrade Project Systems.