share same dll through different web applications without copying

Question

I have two different asp.net web applications both referencing the same dll e.g. SharedLibrary.dll.

I want to know if there is a way of adding some web.config setting to one of the application's config files to avoid the need to have two copies of the dll lying around.

My [simplified] directory structure is as follows:

\root
     \Admin
           \web.config 
           \Addins
                  \AdminWebAppPage.aspx
                  \bin
                      \AdminWebApp.dll
                      \SharedLibrary.dll  <- this is the duplicated dll (I'd like to remove it from here ideally)
     \Websites
              \MyWebsite
                        \webroot
                                \web.config
                                \MainWebPage.aspx
                                \bin
                                    \MainWebsite.dll
                                    \SharedLibrary.dll

Answer 1

I have done this in the past where virtual ROOTS under a website shared a DLL. That is, I had a website with some DLL's and an administrative virtual root underneath it. Since it is a child of the main website it inherits the website's DLL's. But I'm not sure about seperate websites...

Answer 2

If you register the assembly in the Global Assembly Cache (GAC), all your apps can access it without having a copy around. However, from a versioning and deployment perspective, I'd say keeping a per-site copy is preferable.

Clarification: keepin a per-site copy is preferable when the sites are not related. Obviously if a shared library changes, you'd want both the main web site and the admin site to get the updated copy. :-)

Answer 3

If you're on a Vista machine you could look at using a NTFS symbolic link

If you're pre-Vista but on Win2k or later a NTFS Junction Point might help

Answer 4

You can put that DLL in Directory where all web-apps you want this DLL to be shared among have the read rights.

In the Application_OnStart event you can dynamically load the assembly using this code..

Assembly SampleAssembly;
SampleAssembly = Assembly.LoadFrom("c:\\Sample.Assembly.dll");

And you can also try resolving the reference by using Assembly_Resolve event.