R – Deployment Project dlls cause ‘type x exists in both’ errors

asp.netweb-deployment-project

I have a WebApplication project, a business logic project, and a WebDeployment project for the web app.

When I build solution, the deployment "Release" bin contains 1 dll for each of the projects – so I get one for MyWeb.dll, MyWebBusiness.dll, and MyWebDeploy.dll.

When I try to run the site, it sees the same type in both MyWeb.dll and MyWebDeploy.dll and chokes.

Error message:
CS0433: The type 'AV' exists in both 'c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\root\53d45622\6c032bd2\assembly\dl3\33f3c6b2\abc9430a_285ac901\MyWeb.DLL' and 'c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\root\53d45622\6c032bd2\assembly\dl3\631e5302\0231160d_285ac901\MyWebDeploy.DLL'

Best Answer

Some reasons I can think of:

You have an App_Code directory in your project
You have a CodeFile page directive in the some page markup instead of CodeBehind

Related Solutions

C# – Compile Error CS0433 on pre-compiled ASP.NET 2.0 site

killing Cassini instances as above didn't work for me. ScottGu posted about this issue

setting the batch="false" attribute on the compilation section in web.config worked for me.

<configuration>

   <system.web>
       <compilation debug="false" batch="false"></compilation>
   </system.web>

</configuration>

This tells ASP.NET to dynamically compile individual .aspx/.ascx files into separate assemblies. This avoids the circular reference issue that triggers the exception.

C# – Where does error CS0433 “Type ‘X’ already exists in both A.dll and B.dll ” come from

Theory

When this issue is not caused by a bug in the application (e.g., duplicate class name):

This issue appears to present after a change is made to the application's project that results in a new build (e.g., code/reference/resource change). The issue appears to lie within the output of this new build: for various reasons Visual Studio is not replacing the entire contents of your application's obj/bin folders. This results in at least some of the contents of your application's bin folder being out of date.

When said issue occurs, clearing out the "Temporary ASP.NET Files" folder, alone, does not solve the problem. It cannot solve the problem, because the stale contents of your application's bin folder are copied back into the "Temporary ASP.NET Files" folder the next time your application is accessed, causing the issue to persist. The key is to remove all existing files and force Visual Studio to rebuild every object, so the next time your application is accessed the new bin files will be copied into the "Temporary ASP.NET Files" folder.

Solution

Close Visual Studio
Perform an iisreset
Delete all the folders and files within the "Temporary ASP.NET Files" folder (the path is referenced in the error message)
Delete the offending application's "obj" and "bin" folders
Restart Visual Studio and open the solution
Perform a "Clean Solution" followed by a "Rebuild Solution"

Explanation

Steps 1-2: remove resource locks from the folders/files we need to delete.
Steps 3-4: remove all of the old build files
Steps 5-6: create new versions of the build files

Best Answer

Related Solutions

C# – Compile Error CS0433 on pre-compiled ASP.NET 2.0 site

C# – Where does error CS0433 “Type ‘X’ already exists in both A.dll and B.dll ” come from

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