Could not load file or assembly 'System.ComponentModel.Annotations, Version=4.1.0.0

Question

I have a .NET Standard 1.4 class library that references the System.ComponentModel.Annotations (4.3.0) NuGet package.

I'm then referencing this class library from a .NET Framework 4.6.2 test project. It builds fine, but at runtime I get the following error:

System.IO.FileLoadException occurred HResult=0x80131040
Message=Could not load file or assembly 'System.ComponentModel.Annotations, Version=4.1.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)

I tried adding a reference to the System.ComponentModel.Annotations (4.3.0) NuGet package from the net462 project, but that didn't make any difference.

I tried adding a reference to the .NET Standard library from the net462 project, but still no luck.

Am I missing something here? Is this a known bug, if so is there a work around?

Any help is much appreciated!

use the [bindingRedirect attribute in app.config](https://msdn.microsoft.com/en-us/library/7wd6ex19.aspx) to force usage of the 4.3.0.0 lib — magicandre1981, May 18 '17 at 17:08
For anybody missing Version=4.2.0.0: Installing System.ComponentModel.Annotations 4.4.1 from NuGet Gallery fixed it for me. — user764754, Mar 06 '18 at 13:14
The problem seem to have worsened again in .Net Core 2.1 (used in combination with .Net 4.7.1). System.ComponentModel.Annotations 4.5.0 doesn't seem to be able to find Version=4.2.0.0 no more, forcing you to go back to bindingRedirect oldVersion="4.2.0.0" newVersion="4.0.0.0"/>. Strange that Microsoft is apparently not able to solve this issues with System.ComponentModel.Annotations. They are already there for nearly two years. — JRB, May 31 '18 at 02:18
@JRB you suggestion did not work for me but an adjusted one. I ended up with `` which fixed the problem. — t3chb0t, Jun 08 '18 at 10:36
@t3chb0t : Good that you found a solution. I remember that end of May I first tried oldVersion="0.0.0.0-4.5.0.0" newVersion="4.2.1.0" but in my case that didn't work, probably because my setup is somewhat atypical. Maybe later on I will give your solution a try. — JRB, Jun 08 '18 at 16:57
In my ASP.NET core project, this was my issue and solution: https://stackoverflow.com/a/53032512/538387 — Tohid, Nov 02 '18 at 05:00
@t3chb0t saved my life ! I was trying to use a .NET Standard 2.0 library from a .NET Framework 4.8 WebForms project and I was getting this error. After adding what you mention in the web.config, and adding the System.ComponentModel.Annotation v5.0.0 as nuget package to the project, everything worked OK. Thanks ! — MINDoSOFT, Nov 15 '21 at 11:31
for those who face - WRN: Comparing the assembly name resulted in the mismatch: Build Number issue - the package version 4.4.1 has the same build version number as 4.2.0 — Sahadevan, Oct 19 '22 at 11:16

score 76 · Accepted Answer · edited Nov 09 '20 at 09:17

76

In many cases, this can be solved by adding the following code to the csproj file of your test project:

<PropertyGroup>
  <AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>
  <GenerateBindingRedirectsOutputType>true</GenerateBindingRedirectsOutputType>
</PropertyGroup>

This forces the build process to create a .dll.config file in the output directory with the needed binding redirects.

The reason is that "classic" csproj test projects are true "libraries" and are not considered to need binding redirects by default. But running unit tests requires this. This only becomes an issue if referenced projects need those redirects to work correctly. This usually works when directly installing all NuGet packages that the referenced library uses, but with the new PackageReference style of NuGet packages, it does not.

See other instances where this fix has helped:

Could not load file or assembly Microsoft.Extensions.DependencyInjection.Abstractions, Version=1.1.0.0

When using .Net Standard 1.4 in a library and .Net framework 4.6.1 in and application, unable to load file System.IO.FileSystem, Version=4.0.1.0

edited Nov 09 '20 at 09:17

Aliaaa

1,590
2
16
37

answered May 19 '17 at 21:21

Martin Ullrich

94,744
25
252
217

8

This does not work with .NET 4.6.1 Web apps. This issue seems to be a constant problem when developing against a webapp. The only think I can do that worked was to recompile my webapp and unload it from the solution before debugging IIS manually. This is such a pain to deal with. – RashadRivera Aug 08 '17 at 17:39
2

I can confirm that this does not work in .Net 4.6.1 web apps. – camainc Jul 03 '18 at 20:10
At my solution WPF - WCF - SQL server - I changed in app.config – Gleb B Jul 14 '18 at 07:11
The problem here is that in some more complex solutions autogenerating the BindingRedirects is not working correctly for "System.ComponentModel.Annotations", so your suggestion is helpful in general, but in this cases misses the point. – JRB Oct 11 '18 at 10:01
2021 Does not work anymore dotnet standard – user1034912 Oct 13 '21 at 01:31
3

When you are installing anything above `4.2.0.0` in package manager the assembly version is actually `4.2.1.0` for EVERY single version above that. so the binding redirect that works is `` even though you may have the `4.7.0` or `5.0.0` NuGet package installed. I think its a version compatibility thing that is a pain in the arse for hybrid framework / standard projects. – Piotr Kula May 25 '22 at 18:56

score 21 · Answer 2 · answered Jul 15 '17 at 13:47

21

I had similar problem but none of the above answers helped me. It turns out that solution is very easy, I've just run following command in Package Manager:

Install-Package System.ComponentModel.Annotations -Version 4.1.0

answered Jul 15 '17 at 13:47

Lukasz Cokot

400
2
13

2

No a very satisfactory solution, but this worked for me. – Matt Varblow Jul 25 '17 at 13:43
1

At the time of writing I had to use Version 4.4.1 – Dabblernl Jan 21 '19 at 21:48

score 16 · Answer 3 · answered May 23 '17 at 13:37

16

In my case, I was using 4.0.0, so I fixed it by adding in

<runtime>
<assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
  <dependentAssembly>
    <assemblyIdentity name="System.ComponentModel.Annotations"
                      publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
    <bindingRedirect oldVersion="4.1.0.0" newVersion="4.0.0.0"/>
  </dependentAssembly>

Adapt to your required version.

answered May 23 '17 at 13:37

Guillaume

1,076
10
21

Btw if the change by my answer is applied, this binding redirect should be generated automatically by msbuild when it unifies assembly references during compilation. – Martin Ullrich May 31 '17 at 08:00
2

thanks for me it was – Nick Kovalsky Sep 29 '18 at 07:52
In my case I created console application with .NET Framework 4.7.2, originally with a app.config transformationsm (for Debug/Release), then added Microsoft,EntityFrameworkCore.Sqlite 2.1.4 NuGet package, (VS 2017 15.8.5). It took me litle bit longer to find out, that the existing app.config transformations somehow broke the binding redirections at runtime. (After removing the transformations it was starting to work) – rychlmoj Oct 02 '18 at 13:14
4

When you are installing anything above `4.2.0.0` in package manager the assembly version is actually `4.2.1.0` for EVERY single version above that. so the binding redirect that works is `` even though you may have the `4.7.0` or `5.0.0` NuGet package installed. I think its a version compatibility thing that is a pain in the arse for hybrid framework / standard projects. – Piotr Kula May 25 '22 at 18:57

MiguelSlv · Answer 4 · 2020-01-28T23:49:25.460

This usually happens when visual studio can't figure out the correct bindingRedirect.

Most likely the cause it that the version of the nugget does not match the version of the produced library.

To fix do this:

From package manage console do:

Get-Project –All | Add-BindingRedirect

to regenerate assemblyBinding configuration at the config file
If didn't fix it, then add manually the binding redirection:
```
<dependentAssembly>
    <assemblyIdentity name="System.ComponentModel.Annotations"    publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
    <bindingRedirect oldVersion="0.0.0.0-X" newVersion="Y" />
</dependentAssembly>
```
where:
1. X is the version that can't be load, from the error message
2. Y is the version on your project references. To get it, select the library from the references node, and look for the version on property pane.

When you are installing anything above `4.2.0.0` in package manager the assembly version is actually `4.2.1.0` for EVERY single version above that. so the binding redirect that works is `` even though you may have the `4.7.0` or `5.0.0` NuGet package installed. I think its a version compatibility thing that is a pain in the arse for hybrid framework / standard projects. — Piotr Kula, May 25 '22 at 18:57

score 7 · Answer 5 · answered Feb 14 '22 at 20:39

Credit to @MiguelSlv as my case had to do with using a proper binding redirect. However, be sure that when you deploy your app to beta or production that the binding redirect is in your deployed web.config (not just in your development environment). I ended up using the following binding redirect for the NuGet package System.ComponentModel.Annotations 5.0.0 that is used in a .NET Standard 2.0 class project being consumed by my **ASP.NET MVC web application (.NET Framework 4.7.1)

<dependentAssembly>
<assemblyIdentity name="System.ComponentModel.Annotations" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
<bindingRedirect oldVersion="0.0.0.0-4.2.1.0" newVersion="4.2.1.0" />
</dependentAssembly>

Note that 4.2.1.0 is the version shown under properties, while 5.0.0 is the NuGet package version.

When you are installing anything above `4.2.0.0` in package manager the assembly version is actually `4.2.1.0` for EVERY single version above that. so the binding redirect that works is `` even though you may have the `4.7.0` or `5.0.0` NuGet package installed. I think its a version compatibility thing that is a pain in the arse for hybrid framework / standard projects. — Piotr Kula, May 25 '22 at 18:58

score 3 · Answer 6 · answered Nov 24 '18 at 04:16

Got it working by using assembly redirection as described in: just invoke FunctionsAssemblyResolver.RedirectAssembly() in the begining of your program. https://stackoverflow.com/a/50776946/2705777

using System.Reflection;
using System.Diagnostics;
using System.Linq;

public class FunctionsAssemblyResolver
{
    public static void RedirectAssembly()
    {
        var list = AppDomain.CurrentDomain.GetAssemblies().OrderByDescending(a => a.FullName).Select(a => a.FullName).ToList();
        AppDomain.CurrentDomain.AssemblyResolve += CurrentDomain_AssemblyResolve;
    }

    private static Assembly CurrentDomain_AssemblyResolve(object sender, ResolveEventArgs args)
    {
        var requestedAssembly = new AssemblyName(args.Name);
        Assembly assembly = null;
        AppDomain.CurrentDomain.AssemblyResolve -= CurrentDomain_AssemblyResolve;
        try
        {
            assembly = Assembly.Load(requestedAssembly.Name);
        }
        catch (Exception ex)
        {
        }
        AppDomain.CurrentDomain.AssemblyResolve += CurrentDomain_AssemblyResolve;
        return assembly;
    }

}

This is basically what BenchmarkDotNet does. https://github.com/dotnet/BenchmarkDotNet/blob/db3a8fc0e74229f14ffcc532e3d655256e38d559/src/BenchmarkDotNet/Running/BenchmarkRunnerDirty.cs — John Zabroski, Apr 26 '19 at 21:05
When you are installing anything above `4.2.0.0` in package manager the assembly version is actually `4.2.1.0` for EVERY single version above that. so the binding redirect that works is `` even though you may have the `4.7.0` or `5.0.0` NuGet package installed. I think its a version compatibility thing that is a pain in the arse for hybrid framework / standard projects. — Piotr Kula, May 25 '22 at 18:57

score 2 · Answer 7 · answered Sep 23 '19 at 19:25

Also for 4.2.0.0 version error this is fixed for me in web.config:

  <dependentAssembly>
    <assemblyIdentity name="System.ComponentModel.Annotations" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
    <bindingRedirect oldVersion="0.0.0.0-4.2.1.0" newVersion="4.6.0" />
  </dependentAssembly>
</assemblyBinding>

score 1 · Answer 8 · answered Dec 31 '20 at 10:36

1

Fixed this by installing the same System.ComponentModel.Annotations version I want to use across all the projects in the solution.

answered Dec 31 '20 at 10:36

user14918236

11
1

score 1 · Answer 9 · edited Jul 26 '21 at 19:29

Please Add below dependentAssembly in your web.Config or app.Config file

The following configuration is added under the configuration --> runtime --> assemblyBinding node under:

<dependentAssembly>
        <assemblyIdentity name="System.ComponentModel.Annotations" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-4.2.1.0" newVersion="4.2.1.0" />
      </dependentAssembly>

score 1 · Answer 10 · edited Dec 23 '22 at 07:49

1

I had similar problem too and in my case i just added reference from C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.8.1\System.Windows.Forms.DataVisualization.Design.dll and C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.8.1\System.Windows.Forms.DataVisualization.dll

edited Dec 23 '22 at 07:49

Pranav Singh

17,079
30
77
104

answered Dec 21 '22 at 09:12

Mamat Hidayat

11
1

score 0 · Answer 11 · answered Feb 02 '18 at 14:33

0

For me, none of the other solutions worked.

I resolved this by manually adding a reference to System.ComponentModel.DataAnnotations myself (via project -> References), rather than letting Visual Studio handle it via the light-bulb quick-fix menu.

answered Feb 02 '18 at 14:33

Rich

715
7
19

score 0 · Answer 12 · answered Sep 30 '19 at 09:27

0

I fixed this error by doing the Clean Solution command in Visual Studio 2019.

answered Sep 30 '19 at 09:27

user1605822

99
3
14

score 0 · Answer 13 · answered Feb 02 '20 at 18:52

I have this issue by implementing a helper function redirecting the assembly at the begin (which was suggested in this answer):

public static class FunctionsAssemblyResolver
{
    #region Public Methods

    public static void RedirectAssembly()
    {
        AppDomain.CurrentDomain.AssemblyResolve += ResolveAssemblyOnCurrentDomain;
    }

    #endregion Public Methods

    #region Private Methods

    private static Assembly ResolveAssemblyOnCurrentDomain(object sender, ResolveEventArgs args)
    {
        var requestedAssembly = new AssemblyName(args.Name);
        var assembly = default(Assembly);

        AppDomain.CurrentDomain.AssemblyResolve -= ResolveAssemblyOnCurrentDomain;

        try
        {
            assembly = Assembly.Load(requestedAssembly.Name);
        }
        catch
        { }

        AppDomain.CurrentDomain.AssemblyResolve += ResolveAssemblyOnCurrentDomain;

        return assembly;
    }

    #endregion Private Methods
}

score 0 · Answer 14 · answered Dec 12 '20 at 18:40

0

Linux Users

You may have to install mono if you're trying to generate .exe file from linux system.

See this link on how to install mono on ubuntu 20.04

answered Dec 12 '20 at 18:40

7guyo

3,047
1
30
31

Jess · Answer 15 · 2021-11-02T18:32:50.833

This is actually much easier than hacking config files. Hacking config files is a little scary; you might miss something! Let the IDE do it for you - hopefully it will do it right!

Right click solution
Click Manage Nuget Packages for Solution...
Search for System.ComponentModel.Annotations
Put a check box in your test projects and click Install

Now my unit tests run! Awesome!

It is still possible that you will need to use @Guillaume's answer if you have app.config files in your unit test project.

Could not load file or assembly 'System.ComponentModel.Annotations, Version=4.1.0.0

15 Answers15

Linked