Side-by-side (SxS) assemblies allow applications to specify which version of a system DLL or classic COM component to use, such as MDAC, MFS, MSVCRT, or MSXML. For example, if an Enterprise Services application relies on a particular version of a dependent assembly, you can ensure that this application still uses that version of the assembly even after newer versions have been installed.

To configure SxS assemblies, you need to know the path to the DLL and the path to the application manifest file. The path to the application manifest file is specified using the Application Root Directory property for that application, which can be found in the Component Services Explorer, in the Activation tab of the Properties dialog for that application. The application manifest is an XML file that has information about where a DLL is installed. The manifest is used to create an activation context for the application. Activation contexts allow an application to load a particular DLL version, COM object instance, or custom window version. A manifest looks like the following file excerpt:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?> 
<assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0"> 
<assemblyIdentity publicKeyToken="75e377300ab7b886" type="win32" name="Test4Dir" version="1.0.0.0" processorArchitecture="x86"/> 
<file name="DirComp.dll" hash="35ca6f27b11ed948ac6e50b75566355f0991d5d9" hashalg="SHA1"> 
<comClass clsid="{6C6CC20E-0F85-49C0-A14D-D09102BD7CDC}" progid="DirComp.PathInfo" threadingModel="apartment"/> 
<typelib tlbid="{AA56D6B8-9ADB-415D-9E10-16DD68447319}" version="1.0" helpdir=""/> 
</file> 
</assembly>

You can use the Component Services administrative tool to enter the full path of the application root directory that contains a valid SxS assembly manifest file for that particular COM+ application.

See Also