I am seeing a System.Reflection.ReflectionTypeLoadException at runTime:
Could not load type 'System.IdentityModel.Tokens.ISecurityTokenValidator'
from assembly 'System.IdentityModel.Tokens.Jwt, Version=5.0.0.127, Culture=neutral, PublicKeyToken=31bf3856ad364e35'.":"System.IdentityModel.Tokens.ISecurityTokenValidator
I am using System.IdentityModel.Tokens.Jwt version 5.0.0.127 (nuget package 5.0.0)
I have tried using fuslog to look at the binding log. It finds the dll in my bin directory and the bind succeeds (and it is the correct dll). I've also verified that I don't have this library installed in the GAC.
I used visual studio's object browser and went looking through the dll. I found that JwtSecurityTokenHandler inherits from ISecurityTokenValidator. According to the object browser ISecurityTokenValidtor comes from Microsoft.IdentityModel.Tokens. (I am using nuget package 5.0.0 of that one also).
I manually went through the various nuget dependencies related to these two packages (as well as any others in my project that I thought had a chance of being relevant). Everything appears to check out.
Can anyone explain under what circumstances you would be unable to load a type from an assembly? And can anyone explain to me how to properly resolve the issue with this specific library?
In My case I removed the "Microsoft.IdentityModel.Protocol.Extensions" from my packages. and worked like a charm.
I have a situation where I get a runtime error when running ASP.NET MVC4. I recently migrated to MVC4 from MVC3.
Upon starting the debugger, I instantly get faced with this error message:
The type 'System.Web.Mvc.WebViewPage' exists in both
'c:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET
Files\promotionweb\20a5681f\9ce59023\assembly\dl3\29f671cf\37f0bcf2_4619d001\System.Web.Mvc.DLL'
and
'c:\Windows\Microsoft.NET\assembly\GAC_MSIL\System.Web.Mvc\v4.0_4.0.0.0__31bf3856ad364e35\System.Web.Mvc.dll'
I'm running in IIS 7.5, with a solution setup of the MVC project itself, another C# library plus a console application project.
I've tried all steps mentioned in this answer, descended from a similar question. However it doesnt help at all in my case.
I had some doubts it had to do to different compilations models, so I've tried compiling for x86 and AnyCPU, cleaning all catalogs as mentioned above in-between. Nothing seems to help.
Any ideas what might cause this interference between the GAC and my Temporary ASP.NET files?
Below is quite a story, but I think it might benefit someone else.
First of all, I opened my project inside Visual Studio 2013, and got a complaint. I followed a link from inside VS2013 (cannot find it) to a Microsoft site where it explained how to manually upgrade an MVC3 to MVC4 project. The steps I followed required manual changes to web.config.
One of the changes I made was to modify the version number of the System.Web.Mvc reference. Previously it was 3.0.0.0, and according to the guide 4.0.0.0 was the number to change to. Another step was to go into the NuGet package manager, search for ASP.NET MVC4 and install it. This downloaded version 4.0.0.1 of System.Web.Mvc, as I think that was the correct version of the time the guide was written.
Once done, I compiled the project and got into the never-ending loop of the runtime error in the question that I posted. My project was compiled against version 4.0.0.1 (which seems to be the correct version number according to a windows update). The compilation was correct, but I had the following line in my web.config:
<add assembly="System.Web.Mvc, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
The application was compiled against 4.0.0.1, but was running and searching for 4.0.0.0 and found it in these two places:
c:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET
c:\Windows\Microsoft.NET\assembly\GAC_MSIL
and thew the error. I still do think this part is strange.
My solution was to modify the web.config, changing the assembly reference version as mentioned, and the binding redirects for System.Web.Mvc.
Some other sources:
System.Web.Mvc not functioning as expected after Windows Update
System.Web.Mvc broken after security update
I once had this error. I noticed that it is important that the reference in the project and the add assembly-tag in web.config is the same. What I did was remove the reference to the assembly that was not the same as in web.config and then adding reference with the correct version. I assume you could also do it the other way around.
I am trying to get the async nuget package for .net 4.0 to work but it doesn't seem to work. Ive uninstalled the package, restarted VS 2013, and reinstalled the package about 10 times now. Ive tried manually copying the file and right clicking add > add existing.
Here is the thing I get the following error each time...
Could not load file or assembly 'Microsoft.Threading.Tasks, Version=1.0.12.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified.
So for some reason it is looking for version 1.0.12 but i have only ever installed version 1.0.168 (the latest) so I have no idea on earth why it would be looking for version 12 and I cant find where this setting would be. I tried the packages.config file but it lists it correctly at version 1.0.168
what the heck!? how can I tell this to look for version 1.0.168 instead!! Please help me!
Usually this happens when there is an issue with packages.config. It happened to me a couple of times in the past. Just review your packages.config and make sure that its definition matches with the version you need.
If packages.config is not the issue you can try:
Removing the nugget from the solution (right click on the solution and click manage nugget packages for solution) and re-installing it.
Update nugget packages in all your projects to require the same version of the assembly. Maybe another project is dependent on the old version.
If the reference that you have in the project is for the wrong version, then FIRST uninstall the nugget, then remove the reference from the project and then try to either re-install the nugget, or manually reference the correct assembly.
I also forgot to mention that you can also remove the entry in packages.config, but this is not a good solution (unless you are 100% sure you will only use this library from one assembly), as it will cause problems when difference projects in your solution will need to reference that assembly.
I had a similar issue, where VS insisted on using a specific version, which was not available anymore.
Restoring and rebuilding did not seem to help.
Lastly, I went for msbuild dirs.proj and that resolved the issue for me.
I have a solution with 3 projects:
ParsersBase, that defines an interface IParseRule
ParsersLibrary, that has a reference to ParsersBase and defines a class HtmlImageUrlParseRule : IParseRule
ParsersLibraryTest, that has a reference to ParsersBase and ParsersLibrary and defines a test class with some test methods
When I'm trying to build it, I get a warning:
Reference to type 'AVSoft.ParsersBase.IParseRule' claims it is defined in 'c:\Users\Tim\Dropbox\projects\Image Downloader\ParsersLibrary\bin\Debug\ParsersLibrary.dll', but it could not be found
Why is VS trying to find AVSoft.ParsersBase.IParseRule in ParsersLibrary.dll? ParsersLibraryTest has a reference to ParsersBase; it just doesn't make any sense.
Another way this could happen is if you're using several NuGet packages where one, probably central, package has been updated but some additional functionality packages haven't been.
To work through my recent example - the error was "Reference to type 'ConsumerSubscriptionConfigurator<>' claims it is defined in 'MassTransit', but it could not be found". This is because we had updated MassTransit from 2 to 3, but we had not updated some of the other optional packages (MassTransit.log4net and MassTransit.Autofac) to the same version number. It appears as if assembly redirection had kept everything working until we tried to use one more additional feature.
This error seems to cover a variety of scenarios. In my case, closing and re-opening Visual Studio was the trick. After restarting Visual Studio, I was able to build the project as expected.
I had a similar problem. The site was running a cached version of the dll and not the one I had deployed to the bin directory. I cleared the temporary asp.net folder contents and this solved the issue.
It was my fault, I had a ParsersLibrary project at the start and then renamed it to ParsersBase, but I didn't rename an assembly name, then I added a ParsersLibrary project again.
So, two projects had the same assembly name and it's not very good, is it? :) Assemblies overlap each other, so I have this error.
I had the similar problem: Reference to type 'Func<>' claims it is defined in 'mscorlib', but it could not be found. The problem was following: my solution had Target Framework = 3.5 and I added a reference to Microsoft.Practices.Prism v 4.0 which is built against the framework 4.0.
After changing target framework to 4.0 it worked
It looks like things are a bit easier now than they were before.
As other answer(s) have basically already stated, this error can result from an older version of the same NuGet package not having some of the newer types in it. While in production, this is generally managed through proper versioning, in development, you may end up reusing the same version number when making changes. And that's a likely place where this problem can arise.
To fix this, you can often just clear the cache by doing the following:
In Visual Studio, go to Tools > NuGet Package Manager > Package Manager Settings.
In the pop-up menu, navigate to NuGet Package Manager > General.
In the options on the right, click Clear All NuGet Cache(s).
I hit this exception today. The problem in my case was I had some.package v2.1installed in my host and some.package v2.3 installed in other projects. Update-Package on the host project to v2.3 fixed the issue.
I my case, I tried to test a WPF project with a .NET Core (3.1) test project which could not reference the needed WindowsBase.dll.
Updating/consolidating packages didn't help. Even a clean repo and a restart of Visual Studio didn't solve it for for me.
But rebooting did fix the problem!
#binki's comment helped me;
deleting all .vs, bin, and obj folders, and then reopening the project
ParsersLibraryTest needs to reference ParsersBase. The second part of the error should read "You must add a reference to assembly 'ParsersBase..."
I tried all of the above answers but none resolved my issue.
In the end, I checked in my latest code (GIT), then recloned the repository in a different location.
Not ideal, but at least problem solved.
I had the similar problem: Reference to type 'Func<>' claims it is defined in 'mscorlib', but it could not be found. I have a lib of .Net 4 that was referenced by a .Net 3.5 program. After upgrading both to 4.61 it worked.
Seems like Func<T> is missing in .Net 3.5 and just upgrading that sample app would have been enough.
Further exp: Someone had added a signature in the library project (.Net 4) that uses a Func<T> parameter. But the sample program (3.5) already existed and ran fine so far. But at time of recompilation a dependency of a dependency clashed. Because mscorelib-3.5 had been already loaded. All happens at compilation time.
The only way I could overcome this error was to force uninstall of all nuget packages related and then reinstalling them. Sad but true.
I've just struggled with this error for a while now and finally get around it.
This is how to re-produce it and how I fixed it.
The problem was:
The packages were referenced by Right clicked -> add refernece -> Browse (choose). Then were added again as NuGet packages.
The solution was:
Remove the added references.
Remove the installed packages from .csproj.
Re-install the required packages from NuGet package mangager.
Close Visual Studio and re-open it.
Clean Project.
Build Project.
Note: If you couldn't remove the referenced files (no Remove option on right click) try close Visual studio and re-open it. Or delete or move the dll that were referenced then try again.
For me, I had chosen incorrect project, I was creating a class library project, I had to chose "Class Library (.Net framework)" but I had chosen "Class Library (.Net standard)"
Replacing the same resolved the issue.
The problem was following: my solution had Target Framework = 3.1 and I added a reference to Microsoft.EntityFrameworkCore.SqlServer v 2.0 which is built against the framework .
I had this problem with one of my library projects inside of a solution, after I switched from .NET Framework to .NET Standard. Eventually I just removed the project reference and added it again inside the application project that was reporting the problem. Oddly enough, the only thing that changed was project GUID switching to lower case from the previous upper case.
I have made a dll that wraps around some Google operations. With my first test drive it worked perfectly, but now in a real program, I get a weird assembly reference problem:
FileNotFoundException was unhandled
Could not load file or assembly 'Microsoft.Threading.Tasks, Version=1.0.12.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. Det går inte att hitta filen.
I have heard of System.Threading.Tasks (and am "using" it), but where does Microsoft.Threading.Tasks come in? The exception occurs at the last row of the snippet below.
Google.Apis.Admin.Directory.directory_v1.Data.Groups allGroupsResp = null;
var req = DirectoryService.Groups.List();
req.Domain = _settings.Domain;
allGroupsResp = req.Execute();
And there is no Microsoft.Threading.Tasks in the assembly list.
This is what worked for me:
Open the NuGet console via the Tools menu > NuGet Package Manager > Package Manager Console
From the console type in: update-package Microsoft.Bcl.Async -reinstall
After that, you may be prompted to re-start Visual Studio to finish uninstalling the package. Once you re-start, the package should be re-installed and everything should work.
Sounds like you're using the Google API .Net Client. I suggest using Nuget to install the assemblies as described on the linked page. However, if you download the source, the Microsoft.Threading.Task assmeblies are included and so it seems the code your calling is trying to access those assemblies.
You could manually move that assembly into your directory but I'd usually opt for the Nuget method unless you need to be using a particular build.
I expect you are using the "google-api-dotnet-client". Microsoft.Threading.Tasks is a dll used by this client according to google code:
https://code.google.com/p/google-api-dotnet-client/source/browse/ThirdParty/Microsoft.Threading.Tasks.dll
You probably just have to move this file into your bin directory.
Just install Microsoft.Bcl.Async nuget package!
(if you are using Google.Apis.Oauth2.v2 with UWP app)
There could be several problems - the first one you project where you've referenced this dll is not targeted to .Net4 or you just have not installed .Net4 framework on your box.
I had a similar problem with Microsoft.Threading.Tasks.PDB not being found.
Found the solution here: Cannot find .cs files for debugging .NET source code
TL;DR: VS was trying to debug the .NET framework and I was missing the debug files. But I did not actually need to debug the .NET so i did:
Tools -> Options -> Debugging -> General -> Enable just my Code