MSBuild doesn't copy references (DLL files) if

Question

I have four projects in my Visual Studio solution (everyone targeting .NET 3.5) - for my problem only these two are important:

1. MyBaseProject <- this class library references a third-party DLL file (elmah.dll)
2. MyWebProject1 <- this web application project has a reference to MyBaseProject

I added the elmah.dll reference to MyBaseProject in Visual studio 2008 by clicking "Add reference..." → "Browse" tab → selecting the "elmah.dll".

The Properties of the Elmah Reference are as follows:

• Aliases - global
• Copy local - true
• Culture -
• Description - Error Logging Modules and Handlers (ELMAH) for ASP.NET
• File Type - Assembly
• Path - D:\webs\otherfolder\_myPath\__tools\elmah\Elmah.dll
• Resolved - True
• Runtime version - v2.0.50727
• Specified version - false
• Strong Name - false
• Version - 1.0.11211.0

In MyWebProject1 I added the reference to Project MyBaseProject by: "Add reference..." → "Projects" tab → selecting the "MyBaseProject". The Properties of this reference are the same except the following members:

• Description -
• Path - D:\webs\CMS\MyBaseProject\bin\Debug\MyBaseProject.dll
• Version - 1.0.0.0

If I run the build in Visual Studio the elmah.dll file is copied to my MyWebProject1's bin directory, along with MyBaseProject.dll!

However if I clean and run MSBuild for the solution (via D:\webs\CMS> C:\WINDOWS\Microsoft.NET\Framework\v3.5\MSBuild.exe /t:ReBuild /p:Configuration=Debug MyProject.sln) the elmah.dll is missing in MyWebProject1's bin directory - although the build itself contains no warning or errors!

I already made sure that the .csproj of MyBaseProject contains the private element with the value "true" (that should be an alias for "copy local" in Visual Studio):

<Reference Include="Elmah, Version=1.0.11211.0, Culture=neutral, processorArchitecture=MSIL">
  <SpecificVersion>False</SpecificVersion>
  <HintPath>..\mypath\__tools\elmah\Elmah.dll</HintPath>
    **<Private>true</Private>**
</Reference>

(The private tag didn't appear in the .csproj's xml by default, although Visual Studio said "copy local" true. I switched "copy local" to false - saved - and set it back to true again - save!)

What is wrong with MSBuild? How do I get the (elmah.dll) reference copied to MyWebProject1's bin?

I do NOT want to add a postbuild copy action to every project's postbuild command! (Imagine I would have many projects depend on MyBaseProject!)

Answer 1

I had a similar issue today, and this is most certainly not the answer to your question. But I'd like to inform everyone, and possibly provide a spark of insight.

I have a ASP.NET application. The build process is set to clean and then build.

I have two Jenkins CI scripts. One for production and one for staging. I deployed my application to staging and everything worked fine. Deployed to production and was missing a DLL file that was referenced. This DLL file was just in the root of the project. Not in any NuGet repository. The DLL was set to do not copy.

The CI script and the application was the same between the two deployments. Still after the clean and deploy in the staging environment the DLL file was replaced in the deploy location of the ASP.NET application (bin/). This was not the case for the production environment.

It turns out in a testing branch I had added a step to the build process to copy over this DLL file to the bin directory. Now the part that took a little while to figure out. The CI process was not cleaning itself. The DLL was left in the working directory and was being accidentally packaged with the ASP.NET .zip file. The production branch never had the DLL file copied in the same way and was never accidentally deploying this.

TLDR; Check and make sure you know what your build server is doing.

Answer 2

Take a look at:

This MSBuild forum thread I started

You will find my temporary solution / workaround there!

(MyBaseProject needs some code that is referencing some classes (whatever) from the elmah.dll for elmah.dll being copied to MyWebProject1's bin!)

Answer 3

Changing the target framework from .NET Framework 4 Client Profile to .NET Framework 4 fixed this problem for me.

So in your example: set the target framework on MyWebProject1 to .NET Framework 4

Answer 4

I had the same problem and the dll was a dynamically loaded reference. To solve the problem I have added an "using" with the namespace of the dll. Now the dll is copied in the output folder.

Answer 5

Using deadlydog's scheme,

Y => X => A => B,

my problem was when I built Y, the assemblies (A and B, all 15 of them) from X were not showing up in Y's bin folder.

I got it resolved by removing the reference X from Y, save, build, then re-add X reference (a project reference), and save, build, and A and B started showing up in Y's bin folder.

Answer 6

Referencing assemblies that are not used during build is not the correct practice. You should augment your build file so it will copy the additional files. Either by using a post build event or by updating the property group.

Some examples can be found in other post

• MSBuild to copy dynamically generated files as part of project dependency
• VS2010 How to include files in project, to copy them to build output directory automatically during build or publish