Strange issue with System.Net.Http 4.2.0.0 not found

问题

I have a strange issue, which drives me crazy…

I have a simple Class Library Project (Full .NET Framework, 4.6.1) with a wrapper class for functionality around Cosmos DB. Therefore I have added the “Microsoft.Azure.DocumentDB” NuGet Package 1.19.1 to this project. Other than that, I have a reference to the “Newtonsoft.Json” NuGet Package 10.0.3, as well as to a couple of \"Microsoft.Diagnostics.EventFlow.*\" NuGet Packages.

So far, everything compiles without any error.

But as soon as I hit my wrapper class – consumed from a simple Service Fabric Stateless Service (Full .NET Framework 4.6.1) – and try to execute the following line of code:

_docClient = new DocumentClient(new Uri(cosmosDbEndpointUrl), cosmosDbAuthKey);

I get this strange error at runtime:

System.IO.FileNotFoundException occurred HResult=0x80070002
Message=Could not load file or assembly \'System.Net.Http, Version=4.2.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a\' or one of its dependencies. The system cannot find the file specified.
Source= StackTrace: at Microsoft.Azure.Documents.Client.DocumentClient.Initialize(Uri serviceEndpoint, ConnectionPolicy connectionPolicy, Nullable1 desiredConsistencyLevel) at Microsoft.Azure.Documents.Client.DocumentClient..ctor(Uri serviceEndpoint, String authKeyOrResourceToken, ConnectionPolicy connectionPolicy, Nullable1 desiredConsistencyLevel)

Inner Exception 1: FileNotFoundException: Could not load file or assembly \'System.Net.Http, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a\' or one of its dependencies. The system cannot find the file specified.

I have absolutely no clue, why the System.Net.Http assembly is not found at all – there is even a assembly reference in my class library project to the .Net Framework Assembly “System.Net.Http 4.0.0.0”.

What I also do not understand is, that there is this weird binding redirect to 4.2.0.0 – where is that one coming from? To get around this one, I tried to add the following redirect to the app.config of the Service Fabric Service (which is consuming the class library):

But still no difference, I still get the error at runtime.

Anybody having a clue? Anybody having seen such issue?

Thanks and regards, OliverB

回答1:

The problem you're facing is related to Visual Studio, especially 2017 which is shipped with System.Net.Http v4.2.0.0. However, adopting the new way whereby any references should be done via NuGet, latest version of System.Net.Http which is 4.3.3 contains the dll version 4.1.1.2.

The problem is that VS at build time and at run time as well will ignore your reference and it will try to reference the DLL it knows about.

How to fix it:

make sure that any references to System.Net.Http are done via NuGet
Build time errors: change extension of System.Net.Http.dll (or move it somewhere else...basically get rid of it) that is shipped with VS 2017 (c:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Microsoft\Microsoft.NET.Build.Extensions\net461\lib\); if you've got a different version then the path will slightly differ, not much though
Runtime errors: add an assembly binding redirect

If you look online on google you'll find a few open issues with Microsoft about this, so hopefully they'll fix this in the future.

Hope this helps.

Update:

When looking at finding some permanent fixes for this issue to work on the build agents, noticed that if you migrate to the new NuGet PackageReference model (in .csproj not in packages.config) tends to work better. Here's a link to the guide on how to do this upgrade: https://docs.microsoft.com/en-us/nuget/reference/migrate-packages-config-to-package-reference

回答2:

Removing binding redirect worked for me, you can try removing it:

<bindingRedirect oldVersion="0.0.0.0-4.2.0.0" newVersion="4.2.0.0" />

回答3:

An addition to the answer @AndreiU already gave and how to reproduce runtime errors locally.

I got the runtime error below when deploying to Azure, not locally.

{"Message":"An error has occurred.","ExceptionMessage":"An error occurred when trying to create a controller of type 'OrderController'. Make sure that the controller has a parameterless public constructor.","ExceptionType":"System.InvalidOperationException","StackTrace":" at System.Web.Http.Dispatcher.DefaultHttpControllerActivator.Create(HttpRequestMessage request, HttpControllerDescriptor controllerDescriptor, Type controllerType)\r\n at System.Web.Http.Controllers.HttpControllerDescriptor.CreateController(HttpRequestMessage request)\r\n at System.Web.Http.Dispatcher.HttpControllerDispatcher.d__1.MoveNext()","InnerException":{"Message":"An error has occurred.","ExceptionMessage":"Could not load file or assembly 'System.Net.Http, Version=4.2.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified.","ExceptionType":"System.IO.FileNotFoundException","StackTrace":" at Company.Project.Service.CompanyIntegrationApiService..ctor(Uri baseAddress)\r\n at Company.Project.BackOffice.Web.Controllers.OrderController..ctor() in C:\projects\company-project\src\Company.Project.BackOffice.Web\Controllers\Order\OrderController.cs:line 30\r\n at lambda_method(Closure )\r\n at System.Web.Http.Dispatcher.DefaultHttpControllerActivator.Create(HttpRequestMessage request, HttpControllerDescriptor controllerDescriptor, Type controllerType)"}}

When I started looking at assemblies I could see that my web project and service project targeted different versions for System.Net.Http.

Web project:

Service project:

It's easy to think that this is caused by a mismatch in versions but the key here is to look at the error The system cannot find the file specified..

Looking at the path property we can see that the web project targets a .Net Framework assembly while the service targets an assembly from Visual Studio 2017. Since the server does not have Visual Studio 2017 installed, the runtime error will occur.

Web path:

C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.1\System.Net.Http.dll

Service path:

C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Microsoft\Microsoft.NET.Build.Extensions\net461\lib\System.Net.Http.dll

Something as simple as setting Copy Local to true can fix the problem, however not in all cases.

In order to reproduce the error on your local machine, simply remove the needed System.Net.Http.dll from the Visual Studio specific folder. This will will give you the runtime error and probably some build errors. After these are fixed everything should work, at least it did for me.

If you have installed System.Net.Http via NuGet check which assembly is used by looking at the .csproj version. System.Net.Http 4.3.4 gives the following assembly for example:

<Reference Include="System.Net.Http, Version=4.1.1.3, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
  <HintPath>..\packages\System.Net.Http.4.3.4\lib\net46\System.Net.Http.dll</HintPath>
  <Private>True</Private>
  <Private>True</Private>
</Reference>

If you use a build server like Jenkins, TeamCity or AppVeyor the runtime missing .dll might exist there as well. In this case it might not help to use NuGet version of System.Net.Http or deleting the missing .dll locally. To solve this error look at the version that is not found and the specific PublicKeyToken. After that create a binding redirect in either Web.config or App.config depending on your project. In my case I would like to use 4.0.0.0 instead:

<dependentAssembly>
  <assemblyIdentity name="System.Net.Http" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
  <bindingRedirect oldVersion="0.0.0.0-4.2.0.0" newVersion="4.0.0.0" />
</dependentAssembly>

A good Github thread about the issue:

https://github.com/dotnet/corefx/issues/22781

回答4:

I encountered this error when I deployed a web service to one of our servers. The project targeted .Net framework 4.7.2, which wasn't installed on the server. Installing the 4.7.2 framework on the server corrected the problem.

回答5:

What I did to fix the issue was removed all the bindings from the web.config and did a

Update-Package -reinstall

This removed a bunch of the old bindings that probably do not need to be there and actually did a good cleaning.

回答6:

One simple solution I found that downgrade the target framework for web project to 4.6.

I create client and web application, client having .net framework 4.7.1 and web having the same and I am facing same issue, when I downgrade target .net framework for web it's work for me.

回答7:

I just installed System.Net.Http using NuGet. You can grab it here:

https://www.nuget.org/packages/System.Net.Http/

The ASP.NET MVC project I'm working on targets .NET 4.6.1. It works perfectly on my machine while debugging in IIS Express with Visual Studio 2019.

The problem happened when trying to run the application deployed to Azure. I was getting this error:

Could not load file or assembly 'System.Net.Http, Version=4.2.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies.

What really worked in my case was opening the .csproj file and searching for System.Net.Http like in the following screenshot...

See that the .csproj file has the version 4.1.1.3:

<Reference Include="System.Net.Http, Version=4.1.1.3, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">

The <HintPath> actually points to the ..\packages folder from Nuget, that is, this is the real version installed by Nuget. Once deployed this specific version will also be restored on the server side and everything should work with a bind redirect.

... and so the binding redirect should mention this specific version in Web.config like this:

<dependentAssembly>
    <assemblyIdentity name="System.Net.Http" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
    <bindingRedirect oldVersion="0.0.0.0-4.2.0.0" newVersion="4.1.1.3" />
</dependentAssembly>

This fixed the problem in my case after a couple of commits to Azure Kudu. The Azure web site finally started with no errors.

回答8:

After struggling with this for a couple of days I finally got the .Net 4.7.2/System.Net.Http problem fixed for my project. In addition to changing the *.csproj file to target the framework version 4.7.2 I had to also update app.config in the projects from

<supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.6.1" />

to:

<supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.7.2" />

回答9:

I had the same problem. In the end I solved it by changing the Deploy-FabricApplication.ps1 to something like this

$binFolder = "$LocalFolder\..\..\..\..\Bin"

$httpDllLocation = "$binFolder\System.Net.Http.dll"
$codeFolder = "$ApplicationPackagePath\[ProjectName].ServicesPkg\Code"
$configFile = "$codeFolder\[ProjectName].Services.exe.config"

Copy-Item $httpDllLocation -Destination $codeFolder 

$appConfig = [xml](cat $configFile)
$appConfig.configuration.runtime.assemblyBinding.dependentAssembly | foreach {

    $name = $_.assemblyIdentity.name
    #Write $name
    if($name -eq 'System.Net.Http')
    {
        Write 'System.Net.Http changed'

        $_.bindingRedirect.newVersion = '4.2.0.0'
    }
}
$appConfig.Save($configFile)

I found an 4.2.0.0 System.Net.Http.dll that is x64. Before deploying this script copies the dll to the package directory and changes the config file to explicitly use this file. I also wrote a blog about my System.Net.Http problems at http://gertjanvanmontfoort.blogspot.nl/2017/11/systemnethttp-dll-version-problems.html

Do not forget to replace the [ProjectName] with your own project name

Hope this helps, feel free to ask

回答10:

For me was something really strange. Needed hours of debugging after found what was the issue. It did not happen locally but only when using jenkins to build the project.

I had a small library using dotnet standart 2.0 and the main project was WCF project which is based on normal .NET(mine was specifically v4.6.1). But in the startup class of the dotnet standart library I had some code that looked like this:

public static class CoreModule
{
    public static IServiceCollection AddStaticDataConfiguration(
        this IServiceCollection services, Func<IServiceProvider, IStaticDataConfiguration>  staticDataConfiguration) 
    {  
        services.TryAddSingleton(staticDataConfiguration);
        services.TryAddSingleton<Func<HttpClient>>(x =>
        {
            var configuration = staticDataConfiguration(x);

            return configuration.ClientResolver ?? (() => new HttpClient());
        });
        return services;
    }
}

IStaticDataConfiguration interface looks like below:

public interface IStaticDataConfiguration
{
    //..... some stuff

    Func<HttpClient> ClientResolver { get; set; }
}

This interface resides inside of the dotnet standart library while the implementation is outside of it(its located in WCF project).

From outside of the library I was calling the AddStaticDataConfiguration method like below:

serviceCollection.AddStaticDataConfiguration(p =>
{
    var staticDataConfig = p.GetService<IStaticDataConfiguration>();
    return new StaticDataProviderConfiguration
    {
        //...some other stuff
        ClientResolver = () => restRequestFactory.GetInstrumentedClient("StaticDataService") //this returns an HttpClient
    };
});

The problem is that I am passing a Func<HttpClient> from a normal .NET project to a dotnet standart library which for some crazy reason dotnet standart does not like and maybe it thinks HttpClient is coming from different classes, as a result throwing System.Net.Http 4.x.x.x not found exception. When removed the code to not accept a HttpClient from a normal .NET project but creating a new func inside the library itself its happy and working fine. Hope this might help somebody else since this error is happening for so many reasons :)

回答11:

My solution was similar to @Raquib's. My project was 4.7.2 and worked just fine on my PC. Whenever I deployed to our dev server I would get the issue mentioned in the question. Turns out the highest .net version on the server was 4.6.1. Downgrading my project to 4.6.1 fixed the problem. Upgrading the server's .net version was not an option for me.

回答12:

First delete from your local filesystem:

C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\MSBuild\Microsoft\Microsoft.NET.Build.Extensions\net461\lib\Syste.Net.Http.dll

Then remove all references in Projects and, add 4.0 reference.
This solved my problem to me.

来源：https://stackoverflow.com/questions/47570912/strange-issue-with-system-net-http-4-2-0-0-not-found

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.net

visual-studio-2017

dotnet-httpclient

service-fabric-stateless