Sharing Entity Framework Library across multiple projects

Question

We have an Entity Framework project with several models set up using .NET 4 and VS2010. Then we have several projects that need to use this entity project. We successfully compiled the EF project into a DLL. We have also successfully added the EF dll reference into multiple projects which is working great.

The problem is now that we have several programs (ASP.NET and console apps) that reference this EF dll and the dll is copied locally for each calling program, when we make a change to the EF dll, we then have to go into each and every project and replace the EF dll with the new build.

I've done a lot of searching for sharing libraries and even EF projects across multiple projects. While I have found several, I can't seem to find a good example that I can make work for my situation or that isn't so old that it's irrelevant.

That is the general issue I'm having. To give a better idea of the issues I'm encountering, I will focus on one particular project. This is an ASP.NET webform project for in intranet. If we add the EF dll reference and allow the project to copy the dll locally, the EF works fantastically. However, because we have multiple project we now need to try and centralize the EF dll somewhere where it can be shared by the multiple processes. I am not trying to set this up so that one EF dll is accessed across multiple server. I am happy to install a copy of the DLL on individual servers if necessary.

My desire is to create a "common libraries" directory on each server, simplified example "C:\OurLibraries". We would then put or EF dlls (and maybe others later) into this folder and allow the various programs/processes to access the common copy of the EF dll. I've made sure the "local copy" of the EF dll has been removed from the intranet project and added a reference to the "C:\OurLibraries\OurEF.dll" file. Everything builds fine and the intranet project works fine until it tries to display a page that has references the EF and then displays an error message:

"Could not load type 'EntityNS.ProductDBEntity'."

If I turn on "local copy" in the reference, the intranet site works fine again. I cannot seem to find that magic setting that will allow me to share the EF dll.

I have tried the following things based on various posts, but with no success:

• Signing the assembly and adding to the GAC. Experienced the same issue as having it in "C:\OurLibraries"

• Adding the "C:\OurLibraries" directory to the PATH environment variable.

• Changed my connection string for the EF in my intranet web.config file to remove the "OR's" from the string: /Ecomedate.csdl|res:///Ecomedate.ssdl|res:///Ecomedate.msl;provider=System... to ;provider=System...

(based on this post: Sharing Entity framework objects across projects?)

I've spent many hours working on this and searching forums and posts. I know there has got to be a way to do this otherwise code reuse and DLL sharing seems useless, so any help you can suggest would be appreciated.

Here is are additional efforts that I have made and in response to some of the post so far.

Also here is what I have experienced with the GAC so far. - on a computer with VS2010 installed, the gacutil is located in C:\Program Files\Microsoft SDK... and from forum on questions "Where is the gacutil" the general tone is that gacutil is now considered a dev tool and not intended for use in prod environments. Gacutil is not part of the Server 2008 or .Net 4 framework, so there are several suggestions on how to deploy and deal with GAC dlls

• first, the old way of installing, using the gacutil, but by using psexec to copy and call gacutil on the production server. I can get psexec to run the gacutil from a local dev box to a prod server and get a return code of 0, success, however I cannot find a way to actually view that it is installed on the production server, because there is not gacutil on prod server, I can't use someting like gacutil /l DataEntity.dll to view info on installed dll...if it even installed correctly.
• I tried copying the gacutil.exe and gacutil.exe.config files to production server to try and run from there. While the program run and gives the version number of the gacutil, it doesn't respond to any command line switches such as gacutil.exe /i DataEntity.dll or gacutil.exe /l DataEntity. It just displays the gacutil version info again and stops.
• Someone suggesed on a forum to installing the Microsoft SDK on the prod machine. While I might have to consider this due to lack of success so far, I really don't like the idea of installing an SDK on my production evironments.
• I tried to find tools such as the Remote GAC Manager to view and manage, but the last development on that opensource project was 2008, so when I try to use it to veiw the GAC, it is wanting to show me c:\Windows\assembly gac dlls, but .NET 4 now uses C:\windows\Microsoft.NET\assembly to store GAC dlls, so I can's seem to find any way to view or maintain DLLs on the remote production server's gac. If I run a dir DataEntity.dll /s command at c:\windows in the command prompt, I find the dll embedded in the C:\Windows\Microsoft.NET\assembly\GAC_MSIL directory, but if I try to look at the file through explorer in C:\Windows\Microsoft.NET\assembly\GAC_MSIL, I cannot see the dll, so I cannot find a tool that allows me to manage (install, list, uninstall) the DLLs in C:\Windows\Microsoft.NET\assembly\GAC_MSIL on the server 2008 production server.
• There was a suggestion to install dlls into gac via drag and drop. I am trying to automate our deployment process, so having to manually drag and drop doesn't make a lot of sense. Does a copy to the C:\Windows\Microsoft.NET\assembly\GAC_MSIL directory work too? I've tried it, but again since I cannot find a tool that will let me see the installed/registered DLLs I can't tell if it worked or not.
• another suggestion was to create an installer that would just install into the GAC. I tried this method and ran into a couple of issues. First it was a very manual process. I could not figure out how to get it to uninstall the old dll from GAC and then install the new version of DLL in gac; it kept insisting that I uninstall the previous installation first. Second, when I tried to uninstall the dll, it kept saying that it was in use by another application. I tried restarting and then uninstalling it, but no go. I finally figured out it was IIS and had to shutdown IIS, uninstall, restart, install, and then restart IIS. This is a pain in the but to try and automate.

Seems like there should be a better way to deploy dlls to a production environment into a shared directory. I simply want to try and put the DataEntity.dll in a c:\MyLibraries directory and have the processes access that one copy of the DLL. Microsoft does it with the C:\Program Files\Common Files, so it should be possible, but I have now spent days trying to find a way that works that would considerabley reduce the maintenance efforts imposed by the GAC or installer options, reduce the number of duplicate dlls, and avoiding overlooking replacing dlls if allowed to 'copy locally'.

Answer 1

the best solution for your problem is using Web Services.web services are created for this purpose.You can build a WCF service library and then use it's methods in all of your projects.

Good Luck