Ever since I've been using the (relatively) new .NET Standard Library project type in Visual Studio, I've been having some problems getting a complete set of DLL files that are required by my project.
The problem is usually limited to 3rd-party libraries which I reference as NuGet packages. I've noticed that these don't get copied to the output folder of my project when I build it. This didn't use to be the case in classic project types.
While I can appreciate the de-cluttering effect that this change has brought for .NET Standard projects, I'm now faced with a problem. I sometimes absolutely need to be able to get the entire list of all files that my project depends on!
I have several different cases, where I might require this list for one reason or another, but the one I believe is most crucial for me, is when I want to gather these files from the csproj itself, right after it's built. In there, I have a custom MSBuild <Target> which should take all the files from the output dir and zip them together for distribution. The problem is, I'm missing all the files that come from NuGet dependencies, because they're not there!
How can I solve this in a general (i.e. not project-specific) way?
UPDATE
There's this deps.json file that contains basically all I'm after and then some. It's just a matter of extracting the relevant information and find the files in the local NuGet cache. But that would involve writing a specialized app and calling it from my target. Before I start writing one myself... Is there something like this already out there somewhere?
I followed this answer and it sort of works.
The suggested thing was to include the following into my csproj:
<CopyLocalLockFileAssemblies>true</CopyLocalLockFileAssemblies>
My main concern is that it also outputs some other DLLs from the framework (such as System.Memory.dll and System.Buffers.dll, among others), which I didn't expect. But maybe that's a good thing. They do seem to be dependencies, just not direct ones. I'll see how it plays out.
If it turns out ok, my only wish would be that this directive was more prominently displayed in project settings (as a simple checkbox, maybe?) so I wouldn't have to hunt the web to find it.
I'm not sure if anyone else has encountered this but often, when I open this particular solution, I see a whole list of errors (see below).
If I double click one of them, then Visual Studio seems to wake up and the errors relating to that particular cs file disappear. This isn't a critical issue and is more on an irritation than anything else but I wonder, is there perhaps something wrong with my code that's causing this false-positive or is it random Visual Studio behaviour?
I had this problem too.
Deleting bin and obj folders not work.
Cleaning solution not work.
Various platform I need to be as is.
Helped me close solution and delete folder .vs, which is often full of problematic mess. After opening solution all false errors disappeared.
As mentioned in a comment, you can do a Clean and Rebuild. If that does not work for you, you can browse to the solution folder and within each of the project folders delete the bin and obj folders. Then perform a build.
You may also want to look into your Configuration Manager and ensure that all of your projects are set to the same Configuration (Debug/Release) and Platform (Any CPU/x86/etc...) and marked to build for that configuration.
Finally, you may also want to check the Build Order for your solution. Ensure that projects are all built in the proper order.
-- Edit:
On thing brought up in comments that I will add here was to make sure that any library projects in the solution are added as Project References rather than referencing the output DLL directly.
Something that has only become evident in later years, and is only relevant upon reflection on this old question, is that the particular solution that we experience this issue in contains a Website project and NOT a WebApplication project. This became evident when we started to look deeper into these recurring errors and noted that they only ever related to codebehind files and all had to do with the Control Name not existing in the current context.
Amongst the various differences between the two project types, it seems that the lack of designer files for each ASP page may be a contributing factor. The error disappears as soon as you double click it potentially indicating that VS is not able to keep track of the control references until you open the relevant page / codebehind file.
We're moving over to a Web Application as a temporary measure.
Hope this insight helps someone else!
I have stumbled into an issue that is really annoying.
When I debug my software, everything runs OK, but if I hit a breakpoint and edit the code, when I try to continue running I get an error:
Metadata file 'XYZ' could not be found
After looking around for a while, I found some a similar issues, but they were all regarding a build failure, which is not my case (this happens only after edit-continue).
What I have tried so far:
My code is compiling and running.
I cleaned the solution and restarted VS.
I made sure that the missing file's project is being build for the configuration I am running (in configuration manager).
I manually built the missing file's project.
Some extra info:
It does not matter what I change, still get the same error (the change is not related to the missing file).
This happens also when I pause and continue (not only breakpoints)
I am running the project using a custom configuration (configuration manager...). When I run it using the default Debug configuration the error does not occur.
Any ideas?
Eventually what solved the issue was:
Clean every project individually (Right click> Clean).
Rebuild every project individually (Right click> Rebuild).
Rebuild the startup project.
I guess for some reason, just cleaning the solution had a different effect than specifically cleaning every project individually.
Edit:
As per #maplemale comment, It seems that sometimes removing and re-adding each reference is also required.
Update 2019:
This question got a lot of traffic in the past, but it seems that since VS 2017 was released, it got much less attention.
So another suggestion would be - Update to a newer version of VS (>= 2017) and among other new features this issue will also be solved
As far as I can tell, this happens when the project dependencies gets messed up for whatever reason (whilst all the inter-project references are still intact). For many cases, it is NOT a code issue. And for those who have more than a few projects, going through them one at a time is NOT acceptable.
It's easy to reset project dependencies -
Select all projects and right click unload
Select all projects and right click reload
Rebuild solution
For those who have an issue in their code or some other issue that's causing this problem you'll obviously have to solve that issue first.
One possible reason could be you have upgraded the some of your projects (in the solution) to higher version e.g. from .NET 4.0 to 4.5 This happened in my case when I opened the solution in VS 2013 (originally created using VS 2010 and .NET 4.0). When I opened in VS 2013 my C++ project got updated to .NET 4.5 and I started to see the problem.
Generally this kind of error comes with human mistakes like if we change the namespace in some improper way, or changing folder names from explorer for current project etc, where compiler is unable to detect sometimes.
I came across the same error, to resolve which I tried few steps. Please follow all the steps :
Clean whole Solution
Right Click on every Project in your solution , Go to Properties and make your Default namespace as well as Default assembly name same as in your code (i.e namespace before class name)
Check Folder names for each project by going through the explorer(Where your project solution is). If not matching with your project names, make it similar (Like step 2) to them.
Remove all your references from each project relevant to another of same solution, and add it again.
In Your Project Solution folder, you will find Visual c# Project file. Right click and open with Notepad. In your initial lines you would find for lines for every project like below:
Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "**Client**", "**Client** \ **Client**.csproj", "{4503E259-0E3B-414A-9074-F251684322A5}"
EndProject
Check again Foldernames (I have highlighted in BOLD) and make it similar to what you did in step 2.
Clean the whole solution again
Build The Solution (If doesn't work try building individual after cleaning again)
Make sure all your dependent projects are using the same .Net Framework version. I had the same issue caused by a dependent project using 4.5.1, while all others were using 4.5. Changing the project from 4.5.1 to 4.5 and rebuilding my solution fixed this issue for me.
XYZ couldn't be found because is not built yet....
Right click on the solution and check Project Dependencies, the Project Build Order should also change according to the dependencies that have been set.
The only thing that worked for me was to delete the Solution User Options (.suo) file. Note that, this is a hidden file.
To locate this file, close your Virsual studio and search for .suo from the file explorer within your project.
PS: a new .suo file will be created again when you rebuild your project and hopefully this newly created one wont give you issues.
I hope that helps someone get rid of this anoying error :).
I had this problem for days! I tried all the stuff above, but the problem kept coming back. When this message is shown it can have the meaning of "one or more projects in your solution did not compile cleanly" thus the metadata for the file was never written. But in my case, I didn't see any of the other compiler errors!!! I kept working at trying to compile each solution manually, and only after getting VS2012 to actually reveal some compiler errors I hadn't seen previously, this problem vanished.
I fooled around with build orders, no build orders, referencing debug dlls (which were manually compiled)... NOTHING seemed to work, until I found these errors which did not show up when compiling the entire solution!!!!
Sometimes, it seems, when compiling, that the compiler will exit on some errors... I've seen this in the past where after fixing issues, subsequent compiles show NEW errors. I don't know why it happens and it's somewhat rare for me to have these issues. However, when you do have them like this, it's a real pain in trying to find out what's going on. Good Luck!
Well, my answer is not just the summary of all the solutions, but it offers more than that.
Section (1):
In general solutions:
I had 4 errors of this kind (‘metadata file could not be found’) along with 1 error saying 'Source File Could Not Be Opened (‘Unspecified error ‘)'.
I tried to get rid of ‘metadata file could not be found’ error. For that, I read many posts, blogs etc and found these solutions may be effective (summarizing them over here):
Restart VS and try building again.
Go to 'Solution Explorer'. Right click on Solution. Go to Properties. Go to 'Configuration Manager'. Check if the checkboxes under 'Build' are checked or not. If any or all of them are unchecked, then check them and try building again.
If the above solution(s) do not work, then follow sequence mentioned in step 2 above, and even if all the checkboxes are checked, uncheck them, check again and try to build again.
Build Order and Project Dependencies:
Go to 'Solution Explorer'. Right click on Solution. Go to 'Project Dependencies...'. You will see 2 tabs: 'Dependencies' and 'Build Order'. This build order is the one in which solution builds. Check the project dependencies and the build order to verify if some project (say 'project1') which is dependent on other (say 'project2') is trying to build before that one (project2). This might be the cause for the error.
Check the path of the missing .dll:
Check the path of the missing .dll. If the path contains space or any other invalid path character, remove it and try building again.
If this is the cause, then adjust the build order.
Are you using a database code generation tool like SQLMETAL in your project?
If so, you may be facing a pluralized to unpluralized transition issue.
In my case, I have noted that some old pluralized (*) table names (upon which SQLMETAL adds, by default, an "s" letter at the end) table references to classes generated by SQLMETAL.
Since, I have recently disabled Pluralization of names, after regerating some database related classes, some of them lost their "s" prefix. Therefore, all references to affected table classes became invalid. For this reason, I have several compilation errors like the following:
'xxxx' does not contain a definition for 'TableNames' and no extension method 'TableNames' accepting a first argument of type 'yyyy' could be found (are you missing a using directive or an assembly reference?)
As you know, I takes only on error to prevent an assembly from compiling. And that is the missing assemply is linkable to dependent assemblies, causing the original "Metadata file 'XYZ' could not be found"
After fixing affected class tables references manually to their current names (unpluralized), I was finnaly able to get my project back to life!
(*) If option Visual Studio > Tools menu > Options > Database Tools > O/R Designer > Pluralization of names is enabled, some SQLMETALl code generator will add an "s" letter at the end of some generated table classes, although table has no "s" suffix on target database. For further information, please refer to http://msdn.microsoft.com/en-us/library/bb386987(v=vs.110).aspx
Hope it helps!
I had this error come up. I followed all of the solutions here but nothing worked. I was using Visual Studio 2013 Professional. I couldn't get the individual project rebuilds to work and I finally figured out there was a circular dependency in my references. Visual Studio does a pretty good job normally of warning you if you are adding a reference to something that references back, but for some reason it didn't in this instance. I added a reference to a project that referenced the project I was working on - and it accepted it. VS bug perhaps?
My 5 cents.
This problem started after a solution wide clean.
I managed to get the problem to go away by setting the Active Solution configuration in: Build -> Configuration manager to release. Then build and set it back to debug again. The build succeeded after that.
Close VS, locate and remove the 'packages' folder from outside of visual studio. Restart VS and build -> all dependencies are reinstalled
Visual Studio 2019 Community 16.3.10
I had similar issue with Release build. Debug build was compiling without any issues.
Turns out that the problem was caused by OneDrive. Most likely one could experience similar issues with any backed-up drive or cloud service.
I cleaned everything as per Avi Turner's great answer.
In addition, I manually deleted the \obj\Release -folder from my OneDrive folder and also logged to OneDrive with a browser and deleted the folder there also to prevent OneDrive from loading the cloud version back when compiling.
After that rebuilt and everything worked as should.
this happens because of the difference of names in the folder name and namespace name. If u create a namespace in a certain name , and later you rename it the namespace will have the old name itself. And the compilation will take the old path to find the .dll and .exe file . To avoid this open the .csproj file of each namespace with a text file , and find the old path in the file.
remove this, clean and rebuild the solution. This worked for me. I spent an entire day working on this problem.
I had this and managed to fix it using this SO answer:
Metadata file '.dll' could not be found
I had to uncheck all of the boxes, click Apply, reenable all of the checkboxes and then click apply again, but it fixed the problem.
I just ran into this issue and after an hour of screwing around realized I had added an aspx file to my product that had the same name as one of my Linq-To-Sql classes.
Class and Page where "Queue".
Changed the page to QueueMgr.aspx and everything built just fine.
For a new build, it could be that some dependencies aren't installed. For me it was Crystal Reports.
It happens when one project dll is failing and that is referenced by number of projects. So first fix it and then Build individuals.
I ve had this problem and it has started after importing our solution to TFS as a new project.I came across this topic and found a quick solution with some inspiration from your answers.
All i needed to do is to rebuild the project thats supposedly lost its metadata file and voila , problem solved.
There's also one another silly reason which you should check with patience... as it occurred to me after wasting 4hours searching for answers:
The story to me was that I accidentally changed a small line of code among thousands of c# class files and then trying to rebuild the solution. As you could imagine, I ended up with 40+ meta data file missing errors and with 1 compilation error among them -- which I didn't check carefully, purely thinking all errors were the same!
after 4 hours searching and then accidentally double checking my error list, I found that silly code error, fixed it, compiled, and then error disappeared.
Not a good answer to your problem, but do hope my case wasn't same to yours.
I had the same problem. In my case I had by mistake I had set all the projects apart from the project with the main method as console application.
To resolve I went to every project other than the one with main function and right click> properites > output type > class library
it was happened to me because I've a strange clash in the namespaces:
I had
AssemblyA
with namespace
AssemblyA.ParentNamespace
witch defines ClassA
and in the same assembly another namespace with name
AssemblyA.ParentNamespace.ChildNamespace
witch defines a different ClassA (but with the same name)
I had then in AssemblyA.ParentNamespace IInterfaceB witch had a method that in the beginning returns IEnumerable and a ClassB witch implements IInterfaceB
I had later modified the method in ClassB to return IEnumerable but I've forgot to update the IInterfaceB definition, so the method there was still returning IEnumerable
the fun fact was that the solution still complile if I did a rebuild all, but the tests witch refers AssemblyA didsn't work and returns the "Metadata file could not be found"error.
updating InterfaceB to correctly return IEnumerable as its implementor ClassB did solved the problem, unfortunately the error message was vague and also the fact that the compilation worked makes me suppose that maybe there is something to fix in the compiler
A coworker was running into this problem and the cause was eluding us. Eventually we realized that the project directory (and therefore the path to the NuGet packages) contained %20 (thanks, some Git gui tool which shall not be named) and the error messages showed that the compiler was looking for an very similar-looking path but one which had to %20, rather a space. Apparently something in the build system somewhere performs HTML-decoding on local filesystem paths.
Renamed the working copy directory and everything started working.
I had this issue too.
It started after I did a little folder tidying in my project.
I then tried to compile and got many duplicate class errors. (despite them not being duplicated. I think the linking was just out of wack)
Upon checking these, the errors would all disappear leaving only the "Metadata file ...debug\application.exe could not be found" error.
I solved this by looking in the build output window to find which classes were duplicated.
I would then right click the class name and "go to definition".
there will be two definitions to select from, open them both, the second definition will seem to open the same file again, however the second one will identify as the error source(red underline).
Delete all the code out of the file and save(This will not effect your actual file).
This should now compile correctly.
Ensure that there are no spaces in the path to your project...
I am using Windows 10 with Visual Studio Community 2019 and I was cloning a multi project solution as it was from a GIT repo. I was having this error with all other dependencies in the solution along with a E_POINTER error. Its path, inherited from GIT, had spaces like C:/repos/MY PROJECT NAME/ ...
I deleted it, cloned it again and make sure that its path contained no spaces like C:/repos/MY_PROJECT_NAME/ ...
That fixed my problem.
I had same issue too.
In my case, I recently add an internal class to somewhere in project. One of the dependencies in solution has same class name and both of them are added correctly to references.
I changed my last activity and rebuild, it works.
Be sure that your compiler messages are valid. In my case I catch reference error from there, not listed as an error in Error List.
We have a moderately sized solution, with about 20 projects. In one of them I have my business entities. On compiling any project, visual studio waits and hangs about one and a half minutes on this BusinessEntities project.
I tried our solution in SharpDevelop and it compiles our complete solution, in 18 seconds. Similar timing with MSBuild.
My guess is that VS is trying to find out if the project needs a compile, but this process is about 15 times slower than actually performing the compile!!
I can't switch to the great sharpdevelop, it lacks some small, but essential requirements for our debugging scenarios.
Can I prevent VS from checking this project, And have it compile the projects without such a check, just like sharpdevelop?
I already know about unchecking projects in configuration management to prevent building some projects, but my developers will forget they need to compile this project after updating to latest sources and they face problems that seem strange to them.
Edit: Interesting results of an investigation: The delay happens to one of the projects only. In configuration manager I unchecked all projects, then compiled each of them individually. All projects compile in a few seconds!! The point is this: if that special project is built directly, compiles in a few seconds, if it is being built (or skipped, because it is up-to-date) as a result of building another project that depends on it, VS hangs for about a minute and half, and then decides to compile it (or skip it). My conclusion: Visual studio is checking to know if any files are changed, but for some reasons, for this special project it is extremely inefficient!!
I'd go to Tools -> Options -> Projects and Solutions -> Build and Run and then change the "MSBuild project build [output|build log] verbosity" to Diagnostic. At that level it will include timings which should help you track down the issue.
We had the same problem with an ASP.NET MVC web project running in Visual Studio 2013. We build the project and nothing happens for about a minute or so and then the output window shows that we are compiling.
Here's what fixed it... open the .csproj file in a text editor and set MvcBuildViews to false:
<MvcBuildViews>false</MvcBuildViews>
I had to use sysinternals process monitor to figure this out but it's clearly the cause for my situation. The site compiles in less than 5 seconds now and previously took over a minute. During that minute the Asp.net compilation process was putting files and directories into the Temporary Asp.net Files folder.
Warning: If you set this, you'll no longer precompile your views so you will lose the ability to see syntax errors in your views at build time.
There is the possibility that you are suffering from VS inspecting other freshly built assemblies for the benefit of the currently compiling project.
When an assembly is built, VS will inspect the references of the target assembly, which if they are feshly built or new versions, may include actually loading them in a .Net domain, which bears all the burdens of loading an assembly as though you were going to run it. The build can get progressively slower as it rebuilds more and more projects. When one assembly becomes newer the others do a lot more work. This is one possible explanation for why building by itself, versus already built, versus building clean, all have seemingly relevantly differing results. Its really tht the others changed and not about the one being compiled.
VS will 'mark down' the last 'internal' build number of the referenced assembly and look to see if the referenced assembly actually changed as it rolls through its build process. If its not differnt, a ton of work gets skipped. And yes, there are internal assembly build numbers that you dont control. This is probalby not in any way due to the actual c# compiler or its work or anything post-compile, but pre-compile steps necessary for the most general cases.
There are several reference oriented settings you can play with, and depending on your dev, test, or deployments needs, the functional differences may be irrelevant, however may profoundly impact how VS behaves and how long it takes during build.
Go to the references of one of the projects in Solution Explorer:
1) click on a reference
2) open the properties pane if its not (not the Property Pages or the Property Manager)
3) look at 'Copy Local', 'Embed Interop Types', 'Reference Output Assembly'; those may be very applicable and probably something good to know about regardless. I strongly suggest looking up what they do on MSDN. 'Reference Output Assembly' may or may not show in the list.
4) unload the project, and edit the .proj file in VS as text. look for the assembly reference in the XML and look for 'Private'. This means whether the assembly referenced is to be treated as though its going to be a private assembly from the referencing assemblies perspective, vs a shared one. Which is sort of a wordy way of saying, will that assembly be deployed as a unit with the other assemblies together. This is very important toward unburdening things. Background: http://msdn.microsoft.com/en-us/magazine/cc164080.aspx
So the basic idea here is that you want to configure all of these to be the least expensive, both during build and after deployment. If you are building them together, then for example you probably really don't need 'Copy Local'. Id hate to say more about how you should configure them without knowing more about your needs, but its a very fine thing to go read a few good paragraphs about each. This gets very tricky however, because you also influence whether VS will use the the stale old one when resolving before the referenced one is rebuilt. As a further example explaiing that its good to go read about these, Copy Local can use the local copy, even though its stale, so having this set can be double bad. Just remember the goal at the moment is to lower the burden of VS loading newly built assemblies jsut to compile the others.
Lastly, for now, I can easily say that hanging for only 1.5 mins is getting off very lucky. There are people with much much worse build times due to things like this ;)
Some troubleshooting idea's that have not been mentioned:
Clean solution?
Delete Obj and Bin folders plus the .suo file? FYI, neither Clean nor Rebuild will delete non-build files, eg files copied during a pre-build command.
Turn off VS scanning outside files. Options > tools > environment > document > detect when file is changed outside the environment?
Rollback SVN history to confirm when it started to occur? What changed? If the project file on day 1 takes the same time, recreate the project, add all the files and build.
Otherwise could you please run Process Monitor and let us know what Visual Studio is doing in the prep-build stage?
Sounds silly, but remove all breakpoints first. It sped up my pre-build checks massively - still don't know why though.
Based on the (limited) information provided one possibility is that there could be a pre-build action specified in the project file that is slow to compile.
Try disabling platform verification task as described here.
If your individual projects are compiling correctly then all you can do is change order of compilation by setting dependent projects explicitly in configuration.
Try to visualize your project dependency hierarchy and set dependent projects. For example, if your business entities project is referenced in each project, then in configuration of each project, this project must be selected as dependent.
When an explicit build order is not set, visual studio is analyzing projects to create an order of building project. Setting explicit dependent projects wiki make visual studio skip this step and use the order provided by you.
With such an extreme delay on a single project and no other avenue seeming to provide a reason I would attempt to build that specific project while running procmon from sysinternals and filter out all the success messages. You could probably also narrow it down to just the file system actions as well. From your description I might guess that the files are being locked by an external source like the event collection or workflow management process services.
Other things to consider would be whether or not this is a totally clean build machine or if it has been used to perhaps test the builds as well? If so, is there a chance that someone mapped an IIS application path to the project directly or registered it as a service location?
If you run procmon and see no obvious locks or conflicts I would create a totally new solution and project and copy the files over to see if that project also has the same delay. If it does have the same delay I would create a sample project of the same type but generic data (essentially empty) and see if that too is slow. If the new project with the same files builds fine you can then diff the directories to see what the variance is that causes the problem (perhaps a config or project setting).
For me, thoroughly disabling code analyzers helped per instructions here:
https://learn.microsoft.com/en-us/visualstudio/code-quality/disable-code-analysis?view=vs-2019#net-framework-projects.
I thought my code analyzers were already off, but adding the extra xml helped.
Thanks Kaleb's for the suggestion to set "MSBuild project build [output|build log] verbosity" to Diagnostic. The first message took more than 10 seconds to display:
Property reassignment: $(Features)=";flow-analysis;flow-analysis" (previous value: ";flow-analysis") at C:\myProjectDirectory\packages\Microsoft.NetFramework.Analyzers.2.9.3\build\Microsoft.NetFramework.Analyzers.props (32,5)
Which led me to the code analyzers.
Just in case someone else trips into this issue:
In my case the delay was being caused by an invalid path entry in "additional include directories" that referred to a non accessible UNC location.
Once this was corrected, the delay disappeared.