MSBuild doesn t copy references DLL files if using project dependencies in solution

Question

I have four projects in my Visual Studio solution  everyone targeting  NET 3 5  - for my problem only these two are important    MyBaseProject  lt - this class library references a third-party DLL file  elmah dll  MyWebProject1  lt - 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     lt Reference Include  Elmah  Version 1 0 11211 0  Culture neutral  processorArchitecture MSIL  gt     lt SpecificVersion gt False lt  SpecificVersion gt     lt HintPath gt    mypath   tools elmah Elmah dll lt  HintPath gt         lt Private gt true lt  Private gt     lt  Reference gt     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

User · Answer

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

User · Answer

I just had the exact same problem and it turned out to be caused by the fact that 2 projects in the same solution were referencing a different version of the 3rd party library    Once I corrected all the references everything worked perfectly

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This requires adding a  targets file to your project and setting it to be included in the project s includes section   See my answer here for the procedure

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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

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I m not sure why it is different when building between Visual Studio and MsBuild  but here is what I have found when I ve encountered this problem in MsBuild and Visual Studio   Explanation  For a sample scenario let s say we have project X  assembly A  and assembly B   Assembly A references assembly B  so project X includes a reference to both A and B   Also  project X includes code that references assembly A  e g  A SomeFunction     Now  you create a new project Y which references project X   So the dependency chain looks like this  Y    X    A    B  Visual Studio   MSBuild tries to be smart and only bring references over into project Y that it detects as being required by project X  it does this to avoid reference pollution in project Y  The problem is  since project X doesn t actually contain any code that explicitly uses assembly B  e g  B SomeFunction     VS MSBuild doesn t detect that B is required by X  and thus doesn t copy it over into project Y s bin directory  it only copies the X and A assemblies   Solution  You have two options to solve this problem  both of which will result in assembly B being copied to project Y s bin directory    Add a reference to assembly B in project Y  Add dummy code to a file in project X that uses assembly B    Personally I prefer option 2 for a couple reasons    If you add another project in the future that references project X  you won t have to remember to also include a reference to assembly B  like you would have to do with option 1   You can have explicit comments saying why the dummy code needs to be there and not to remove it  So if somebody does delete the code by accident  say with a refactor tool that looks for unused code   you can easily see from source control that the code is required and to restore it  If you use option 1 and somebody uses a refactor tool to clean up unused references  you don t have any comments  you will just see that a reference was removed from the  csproj file    Here is a sample of the  dummy code  that I typically add when I encounter this situation          DO NOT DELETE THIS CODE UNLESS WE NO LONGER REQUIRE ASSEMBLY A        private void DummyFunctionToMakeSureReferencesGetCopiedProperly DO NOT DELETE THIS CODE                    Assembly A is used by this file  and that assembly depends on assembly B             but this project does not have any code that explicitly references assembly B  Therefore  when another project references            this project  this project s assembly and the assembly A get copied to the project s bin directory  but not            assembly B  So in order to get the required assembly B copied over  we add some dummy code here  that never            gets called  that references assembly B  this will flag VS MSBuild to copy the required assembly B over as well          var dummyType   typeof B SomeClass           Console WriteLine dummyType FullName

User · Answer

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

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Using Visual Studio 2015 adding the additional parameter      deployonbuild false   to the msbuild command line fixed the issue

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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

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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

User · Answer

Make sure that both projects are in the same  net version also check copy local property but this should be true as default

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I just deal with it like this   Go to the properties of your reference and do this   Set  Copy local   false  Save Set  Copy local   true  Save   and that s it   Visual Studio 2010 doesn t initially put               lt private gt True lt  private gt      in the reference tag and setting  copy local  to false causes it to create the tag   Afterwards it will set it to true and false accordingly

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Another scenario where this shows up is if you are using the older  Web Site  project type in Visual Studio   For that project type  it is unable to reference  dlls that are outside of it s own directory structure  current folder and down    So in the answer above  let s say your directory structure looks like this     Where ProjectX and ProjectY are parent child directories  and ProjectX references A dll which in turn references B dll  and B dll is outside the directory structure  such as in a Nuget package on the root  Packages   then A dll will be included  but B dll will not

User · Answer

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

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I had the same problem   Check if the framework version of your project is the same of the framework version of the dll that you put on reference   In my case  my client was compiled using  Framework 4 Client  and the DLL was in  Framework 4

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The issue I was facing was I have a project that is dependent on a library project  In order to build I was following these steps   msbuild exe myproject vbproj  T Rebuild msbuild exe myproject vbproj  T Package   That of course meant I was missing my library s dll files in bin and most importantly in the package zip file  I found this works perfectly   msbuild exe myproject vbproj  T Rebuild Package   I have no idea why this work or why it didn t in the first place  But hope that helps

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Including all referenced DLL files from your projectreferences in the Website project is not always a good idea  especially when you re using dependency injection  your web project just want to add a reference to the interface DLL file project  not any concrete implementation DLL file    Because if you add a reference directly to an implementation DLL file project  you can t prevent your developer from calling a  new  on concrete classes of the implementation DLL file project instead of via the interface  It s also you ve stated a  hardcode  in your website to use the implementation

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If you are not using the assembly directly in code then Visual Studio whilst trying to be helpful detects that it is not used and doesn t include it in the output  I m not sure why you are seeing different behaviour between Visual Studio and MSBuild  You could try setting the build output to diagnostic for both and compare the results see where it diverges   As for your elmah dll reference if you are not referencing it directly in code you could add it as an item to your project and set the Build Action to Content and the Copy to Output Directory to Always

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I just ran into a very similar issue  When compiling using Visual nbsp Studio nbsp 2010  the DLL file was included in the bin folder  But when compiling using MSBuild the third-party DLL file was not included   Very frustrating  The way I solved it was to include the NuGet reference to the package in my web project even though I m not using it directly there

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As Alex Burtsev mentioned in a comment anything that   s only used in a XAML resource dictionary  or in my case  anything that   s only used in XAML and not in code behind  isn t deemed to be  in use  by MSBuild    So simply new-ing up a dummy reference to a class component in the assembly in some code behind was enough convince MSBuild that the assembly was actually in use

[visual-studio] MSBuild doesn't copy references (DLL files) if using project dependencies in solution

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