I hope someone else has encountered this because its driving me batty.
I recently got a new laptop so I've been setting up my Visual Studio solutions (VS2010 with .NET 4.0) that I saved off my old machine. One of them is a simple console app that I use to simulate some things for testing. It references 2 assemblies that I have in another solution that I am working on now. This used to all work fine as expected but ever since moving to the new machine I get the dreaded "The type or namespace name 'YourAssembly' could not be found (are you missing a using directive or an assembly reference?" error message. The references are clearly shown in the Visual Studio but when the project builds it does not copy them to the bin directory which explains the message. Initially I was just referencing the dlls the way I would any 3rd party dll but I even tried removing that and including the project files in my solution and referencing them that way and still it fails. I've verified that the dlls have their 'Copy Local' property set to true and they do. Its really bizarre because the project references several other dlls that are just 3rd party assemblies (for example NLog, GData, etc) and those all copy over fine but not these two for some strange reason.
Here's one more piece of oddness. If I add some code to the console app that references my assemblies it says it can't find it. If I then re-add the assemblies to the references, the error disappears until I try to build it again and then it returns. Is this a VS bug or what? I've never seen this kind of odd behavior before.
thanks
One case that I have seen that caused the problems you are talking about:
Including references to dlls that are built in-house, linked to a specific version of the dll. Get a new copy of the dll (with a different version number) and the build breaks.
The solution in this case is to set the DLL reference property Specific Version to false. The version of the dll is ignored (in my case, it is safe to ignore it), and the build works properly.
I've also had weird errors like this where the NTFS permissions were set on the old file with an old login, but the new machine didn't like the old permissions.
Also, sometimes the old .sln or .csproj file refers to an odd file path that you can't seem to edit from within VStudio. Try opening those files with notepad and make sure the paths aren't broken. You can usually edit and save with fixed paths and things will work again.
Hans had the answer above but I was unable to find that post through searches so hopefully if you stumble upon this question I can save you several hours of frustration.
For some bizarre reason the 'Target Framework' was defaulting to ".NET Framework 4 - Client Profile" in the project properties. I double checked and it seems to do that whenever I create a new console app. It must be version related thing in VS because I hadn't encountered this issue previously in 2010.
To fix:
Right click on your project, choose properties
Under the main Application tab, set the Target Framework to be your framework of choice but NOT one of the 'Client Profile' options
Save and build as normal
I have a website solution which contains a project with domain classes.
I have added a public auto property (get; set;) to one of the domain classes. A page on the website references this property - it was added to the page using IntelliSense.
The website project builds okay. But when I build the solution, I get the old 'Class does not contain a definition for Property' error. However, if I right click on the property in the aspx.cs file, it takes me right to the declaration in the domain class.
The other website project in the solution can call this property of the class without errors.
Actually using the website fails with the same exception.
Seems like Visual Studio is having some kind of weird episode here.
Any suggestions what might be going wrong?
Thanks
David
Edit: Here are some further observations in a series of steps.
Clean Solution (says 14 succeeded; there are 16 projects in the solution)
Build Solution (says 16 succeeded)
Rebuild Solution (fails as described)
Build Solution (fails as described)
At no point does the website actually work - it always gives the error.
It does appear to precompile successfully.
Edit 2:
I have removed the project reference and re-added it, but the problem remains.
Edit 3:
I have added a new webiste project to the solution and copied all the files across from the existing website to the new website. The problem exists in the new website as well as the existing one.
You might try using System.IO.FileSystemWatcher or one of the SysInternals tools to try to find out if the compiler is accessing an old, cached copy of your assembly somewhere.
Perhaps a reset of IIS or the Application Pools helps a bit?
Also, if the assembly is registered in the GAC, perhaps removing it and installing it back again might help.
Double check the Build Order and/or Dependencies on the project that is having difficulty finding the property. That project should require that the other project(s) build first.
Okay, the problem was that the class I was using (which reportedly didn't contain the particular property) is called Case. Despite C#'s supposed case sensitivity, presumably it somehow clashed with the reserved word 'case', and this caused the problem during compilation.
Fully qualifying the class name fixed the problem, but I think I might just rename the class 'ProbateCase'.
I have to say this is clearly a bug in Visual Studio's compilation process. Not only should 'Case' not equal 'case' in c#, but also the class has existed in my solution for about a year and a half and this problem has never arisen before. Other projects can freely use the class without qualifying its name.
Grumble over. Life goes on.
I am using Visual Studio and a solution with 10 or so projects in (mostly VB, some C#) which have various dependencies set up. Usually when I compile the solution it works fine. Occasionally when I do it I get a build error saying that one of the projects referenced is the wrong version (I think always the same one, possibly may be two that can cause problems). In this case going to the solution explorer and right clicking on the mentioned project and saying "rebuild" followed by another full build makes it work fine.
I assume there is something set up wrong somewhere but I didn't set up the solution myself initially and a quick look through doesn't show anything immediately wrong.
It feels like there is some kind of race condition, that VS is internally setting the version number of the project it needs before that project has been rebuilt and thus gets it wrong or something like that but I'm sure VS should handle all this sort of thing properly.
Can anybody please suggest places that I could check for whether this has been correctly set up...
And I should finally note that since I don't have reliable repro of this I may not be able to respond to questions too quickly. For example the obvious one of "Could you give the exact error message" will have to wait since I didn't think to copy it this morning, it was only after I cleared it up with the above steps that I thought to post here. Similarly any solutions may take a while to confirm.
Edit to add error message:
Indirect reference is being made to assembly ODP version 1.0.3792.16586, which contains '{{CLASSNAME}}'. This Project references a prior version of ODP version 1.0.3791.18659. To use '{{CLASSNAME}}', you must replace the reference to ODP with version 1.0.3792.16586 or higher.
Edit for more apparently relevant details
Since it has been bought up I will clarify that one of the projects is a web project and that it is this one which is generating the above error message.
Further edit
Having looked further there is a copy of ODP.dll in the bin diretory of my web project. Using windows explorer and right clicking, asking for properties and looking at the version it is version 1.0.3791.18659. Having deleted this (actually moved it elsewhere) when doing a build it recreated this file still with that same version number (ie an old version number).
ODP claims to be a project reference too which still makes me think it should just work... :(
Further Further edit
I think now that the problem is that if the ODP project changes then it gets rebuilt but it doesn't necessary cause all the projets that are dependant on it to be rebuilt. So one project might still be built against the old version and one against the new version. If they are then trying to talk between each otehr with objects from ODP then it goes wrong... I need to confirm this but I'm not sure what would need to be done to fix it at the moment. :)
Is the build order correct? I can imagine if you build one project which references the other one, and that one isn't built yet you can have this kind of problem.
Link: http://msdn.microsoft.com/en-us/library/5tdasz7h%28v=VS.80%29.aspx
If you have a website project, are you sure you have set these to be 'project' references rather than 'bin' references - you could be getting some issues this way.
This one has had me stumped for over a year and seems really odd and really obscure. When I build my solution, it complains about a missing referenced DLL. When I rebuild it, the problem goes away. Whenever I do a clean this returns, i.e. have to attempt a build twice before it succeeds.
This is vague, but if warranted I can give a better explanation of solution structure. Since the workaround is simply to build twice, I've never bothered to give it more attention, buts its extremely annoying.
Also, the build fails because it seems the DLL is just absent, so code that references it after fails because of missing types from the DLL. The next time I initiate the build, it works fine.
Update:
The referenced DLL is external (ValidationFramework from CodePlex), located in the source tree.
None of my projects are copying the DLL, just some of them reference it.
This happens in both Debug and Release builds.
Just found it relevant to also add that project A references the ValidationFramework.dll, as does project B, but project B references project A. Now when the build error occurs, its always when the compiler goes to project B, i.e. project A always builds successfully on both first and second build attempts.
Also, when project B fails, I can click "Build" over and over to no effect, it does require a "Rebuild", so whatever "fixes" the problem that is occurring happens prior to building project B (as the problem itself might as well).
Is the missing DLL one of the projects being built in your workspace? Do you have the project dependencies set up so that the DLL project has to be built before the utilizing project is built?
This sounds vaguely familiar. I may have experienced this with vs.net 2003 or 2005 I don't recall. But it exhibited itself like this:
In debug builds the referenced C++/CLI would be copied to consuming assembly folders correctly but when I did release builds it would suddenly break because the referencing projects couldn't find them. It turned out to be a VS.NET bug that I thought was fixed in a service back but in the interim I added some post build steps to move the assembly by brute force to where it need to be.
Do your debug builds seem to work every time?
Recently I started to get this message randomly:
Metadata file '...\Release\project.dll' could not be found in Visual Studio
I have a solution with several projects in it. The current build mode is Debug and all projects' configurations are set to Debug. But when I try to run the main project - sometimes it gives me a few errors, all of which are "Metadata file '...\Release\projectX.dll' could not be found" - and, look, it says about RELEASE folder, though current mode is Debug. Why? I tried to search for reference to "Release\projectX.dll" inside all solution files, and I found one in ResolveAssemblyReference.cache file.
I made a good search over the Internet and found a few people with a similar problem, but there was no solution, or at least no working solution.
I tried to delete references to those projects and read them, but in some time I start getting these errors again.
It seems like a bug. Why does it search for referenced projects in Release folders when I always use Debug mode?
PS. For those who met this problem: I couldn't solve it in an easy way. It disappeared only after I reinstalled Windows :(
Everyone is correct...try everything...(in order of a little to a lot of time wasted)
Do you have bad code? Fix that first.
Clean Solution & Restart Visual Studio
Remove / Add References
Check your build order w/ larger projects and verify
Manually rebuild sub-projects
Manually copy dlls between projects into associated bin folders
Go get some coffee, play some pinball and come back tomorrow...you may think of something else in the meanwhile.
I had the exact same problem. Big visual studio solution with 50+ projects.
All references were added as projects.
Project build order was correct (right click on project and select build order).
However when building some of the higher level projects the "root" project they depended on were not built.
The problem was that these projects were not selected to build under the current configuration (don't know how this happened).
To check this select "Configuration Manager" (Build menu) e check if the problematic projects are set to build.
When you say you deleted references to those projects and re-added them, how did you re-add them, exactly? Did you use the "Browse" tab in the "Add Reference" dialog in Visual Studio? Or, did you use the "Projects" tab (which lists neighboring projects in your solution)?
Edit: If you use the "Browse" tab, and manually add the reference to your .dll that is located in the /Release folder, then Visual Studio will always look for the .dll in that location, regardless of what mode you're currently in (Debug or Release).
If you removed the actual .dll file from the Release folder (either manually or by doing "Clean Solution"), then your reference will break because the .dll does not exist.
I'd suggest removing the reference to ProjectX.dll, and add it in again--but this time, use the "Projects" tab in the "Add Reference" dialog. When you add a reference this way, Visual Studio knows where to get the appropriate .dll. If you're in Debug mode, it will get it from the /Debug folder. If in Release mode, the /Release folder. Your build error should go away, and you also will no longer be (improperly) referencing a Release .dll while in Debug mode.
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.
Section (2):
My particular case:
I tried all the steps above with various permutations and combinations with restarting VS few times. But, it did not help me.
So, I decided to get rid of other error I was coming across ('Source File Could Not Be Opened (‘Unspecified error ‘)').
I came across a blog:
http://www.anujvarma.com/tfs-errorsource-file-could-not-be-opened-unspecified-error/#comment-1539
I tried the steps mentioned in that blog and I got rid of the error 'Source File Could Not Be Opened (‘Unspecified error ‘)' and surprisingly I got rid of other errors (‘metadata file could not be found’) as well.
Section (3):
Moral of the story:
Try all solutions as mentioned in section (1) above (and any other solutions) for getting rid of the error. If nothing works out, as per the blog mentioned in section (2) above, delete the entries of all source files which are no longer present in the source control and the file system from your .csproj file.
I've had this problem before and the only way I've found to solve it is to run Clean Solution and then restart Visual Studio.
For me it's usually the target framework being off (4.5.2 instead of 4.6) If you fix the target framework of the project to match the target framework of the solution and build, a new .dll will be created.
Re-open Visual Studio as Administrator.
Most of the answares say that you need to remove the libraries of your solution, this is true but when you re-add the libraries the error will be shown again. You need to verify if all the libraries referenced have a compatible .net framework with the .net framework of your solution. Then fix all the errors in your code and rebuild the solution.
Did you check the Configuration manager settings? In the project settings dialog top right corner.
Sometimes it happens that between all the release entries a debug entry comes in.
If so, the auto dependency created by the dependency graph of the solution gets all confused.
I've also seen this error in solutions where I have multiple projects (usually netTiers projects where I've updated one or more of the sub-projects to target the 4.0 framework). It can be problematic to remove. Oftentimes it can be resolved, however, by first fixing all other errors in sub-projects (eg, any missing references), individually rebuilding those sub-projects, then removing/adding back any references to those sub-projects in Visual Studio. Personally, I've had little luck resolving this error by cleaning the solution alone.
We recently ran into this issue after upgrading to Office 2010 from Office 2007 - we had to manually change references in our project to version 14 of the Office Interops we use in some projects.
Hope that helps - took us a few days to figure it out.
In my case it was caused by two things (VS.2012):
1) One of the projects was configured for AnyCPU instead of x86
2) A project that was referenced had somehow the "Build" checkbox unchecked.
Do check your Build | Configuration Manager to get an overview of what is being built and for which platform. Also make sure you check it for both Debug & Release as they may have different settings.
In my case, I had some errors in my code. Visual Studio showed the error you had instead of the actual errors, like syntax errors or unknown class names. Try cleaning the solution and building project after project. This way you will discover the actual errors.
Again, this is just what cause the error for me.
I had this problem and took long while to figure it out. Problem came up when I removed projects from solution and replaced those with nuget packages.
Solution seemed to be fine but the .csproj file still contained those projects multiple times as reference.
Seems that VS does not clean that file appropriately. It was still referencing the removed projects under the hood. When manually removed the references from csproj file all works again! wohoo
This problem is due to pdb files or CodeContracts.
To resolve it:
Clean your output folder and rebuild the solution.
Re-Configure the CodeContracts or disable it for temporary build.
We have that problem quite often, but only with references to C++/CLI projects from C# projects. It's obviously a bug deep down in Visual Studio that Microsoft decided not to fix, because it's 'too complex' and they promised an overhaul of the C++ build system which is now targeted for Visual Studio 2010.
That was some time ago, and maybe the fix even went into Visual Studio 2008; I didn't follow up on it any more. However, our typical workaround was
Switch configuration
Restart Visual Studio
Build the solution
I had the same problem myself.
Visual Studio 2013 only told me that it couldn't reference to it, and it couldn't find the metadata. When I opened my solution (which has multiple projects in it) it said that I was using projects lower than the framework version of one of my projects.
So I switched everything to version 4.5, and it worked again.
I seem to recall having a similar problem a few months ago. I solved it temporarily by copying the referenced DLL to the Release folder, thus satisfying Visual Studio's expectations. Later, I discovered the reference to the Release DLL in my actual code. You should try doing a search through the entire project for \release\project.dll.
Also, I have noticed that Visual Studio unit test projects sometimes put a "DeploymentItem" attribute on each of the test methods pointing to your target DLL, and if you switch between Debug and Release, Visual Studio can get confused if the DLL is no longer in the expected location. In my experience, these attributes can be safely deleted if you didn't put them there yourself as part of a "single deployment" scenario.
I had this problem and it was due to an invalid method in the offending library (dll) that did not return a value, e.g.
public bool DoSomething()
{
//I never bothered putting code here....
}
When I commmented this out everything compiled :)
Sometimes VS2010 switches my configuration from Any CPU to Mixed Platforms. When this happens I get this error message.
To resolve it I switch back to Any CPU:
1. Right click on the solution and select properties.
2. Click on Configuration Properties and then the Configuration Manager... button.
3. Under Active solution platform select Any CPU
I find that this usually occurs to me when i still have a method declaration in an interface, which a class implements, but that i had later removed and had forgotten to remove it from the interface as well. I usually just save the entire solution every 30mins n then just revert back to an earlier version if i cant find the error.
I ended up deleting my references (I had added them properly using the projects tab, and they used to build just fine), hand editing my .csproj files and removing bizarre entries that didn't belong -- and setting my outputs for debug and release, x86 and x64 and any cpu to all be "\bin" -- I built it once, then re-added the reference (again, using the projects tab), and everything started working again for me. Didn't have to restart Visual Studio at all.
For me this was caused by the Build target having been rewritten to not output the dll. Removing this to fall back on the default Build target fixed the issue.
For me was to remove/delete entire .vs folder(that is an invisible one) and then:
- Build
- Rebuild
and done.
in my case i was working on a branch off master. so i checked out master branch, ran a build and then checked out my branch. It fixed the issue. If you already are on master, i suggest you check out previous commit and then build it.
It seems to happen when you checkout a solution with multiple projects that have references between them, and you haven't built it before. If you have references directly to the dlls, instead of referencing the project, you'll get this message.
You should always use the Projects tab in the Add Reference dialog to add a reference to a project in the same solution. This way, VS can know the correct order in which to build the solution
same happened to me today as described by Vidar.
I have a Build error in a Helper Library (which is referenced by other projects) and instead of telling me that there's an error in Helper Library, the compiler comes up with list of MetaFile-not-found type errors. After correcting the Build error in Helper Library, the MetaFile errors gone.
Is there any setting in VS to improve this?
I had the same problem. I noticed that my db context (EF4) that was located in the project dll wasn't recognize for some reason. I deleted it and created another one instead. and that solved it for me.
Had the same problem today.
My application, a Windows Forms applications, accidently had a reference to itself. Weird.
Once removed, the error went away.
The reference got added each time I dragged a user control, located in the Windows Forms project itself, to a form.
I had the same problem. Manually removing and adding the dlls did not help. ClassLibraries did not compile for all the projects and were missing in the ...\bin\Debug folder for the project [because I cleaned solution by mistake]. Since the class library did not compile that means there may be some errors somewhere in one of those sub projects.
Solution: Since my dlls were there for the ...\bin\Release folder, I tried to rebuild on Release mode and found an error on one line in one of the sub projects. Solving the error and rebuilding the solution got rid off the build error.