I get an error when I try to load a Visual C++ CLR class library in a docker container

Goal: I have some flat Win32 dll's, that I don't have the source code for.

I want to make a web-service in a docker container that references these dll's

Expected result When I do a compose docker from Visual Studio the web-service should start.

Actual result: I get an error message "Could not load file or assembly 'ClassLibrary1' or one of its dependencies. An attempt was made to load a program with an incorrect format" See the complete error message below.

Here are the steps I went through: I installed Docker on my PC. In Visual Studio I created a new project of type ASP.NET Web Application (.NET Framework). In Visual Studio I added a new project of type CLR Class Library (Visual C++). I added a reference to the CLR-project from the Web Application project. In Visual Studio I pressed the "Docker Compose" button. The error message below appeared. If I don't make the reference to the CLR-project, I don't get the error message.

I hope you can help me. Me and a colleague of mine have used a lot of time on trying to figure it out.

Best Regards Peter Holck.

The complete error message: Could not load file or assembly 'ClassLibrary1' or one of its dependencies. An attempt was made to load a program with an incorrect format. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.BadImageFormatException: Could not load file or assembly 'ClassLibrary1' or one of its dependencies. An attempt was made to load a program with an incorrect format.

Source Error:

 An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.   

Assembly Load Trace: The following information can be helpful to determine why the assembly 'ClassLibrary1' could not be loaded.

=== Pre-bind state information ===
LOG: DisplayName = ClassLibrary1
 (Partial)
WRN: Partial binding information was supplied for an assembly:
WRN: Assembly Name: ClassLibrary1 | Domain ID: 2
WRN: A partial bind occurs when only part of the assembly display name is provided.
WRN: This might result in the binder loading an incorrect assembly.
WRN: It is recommended to provide a fully specified textual identity for the assembly,
WRN: that consists of the simple name, version, culture, and public key token.
WRN: See whitepaper http://go.microsoft.com/fwlink/?LinkId=109270 for more information and common solutions to this issue.
LOG: Appbase = file:///C:/inetpub/wwwroot/
LOG: Initial PrivatePath = C:\inetpub\wwwroot\bin
Calling assembly : (Unknown).
===
LOG: This bind starts in default load context.
LOG: Using application configuration file: C:\inetpub\wwwroot\web.config
LOG: Using host configuration file: C:\Windows\Microsoft.NET\Framework64\v4.0.30319\aspnet.config
LOG: Using machine configuration file from C:\Windows\Microsoft.NET\Framework64\v4.0.30319\config\machine.config.
LOG: Policy not being applied to reference at this time (private, custom, partial, or location-based assembly bind).
LOG: Attempting download of new URL file:///C:/Windows/Microsoft.NET/Framework64/v4.0.30319/Temporary ASP.NET Files/vs/e22c2559/92c7e946/ClassLibrary1.DLL.
LOG: Attempting download of new URL file:///C:/Windows/Microsoft.NET/Framework64/v4.0.30319/Temporary ASP.NET Files/vs/e22c2559/92c7e946/ClassLibrary1/ClassLibrary1.DLL.
LOG: Attempting download of new URL file:///C:/inetpub/wwwroot/bin/ClassLibrary1.DLL.
ERR: Failed to complete setup of assembly (hr = 0x8007000b). Probing terminated.

Stack Trace:

[BadImageFormatException: Could not load file or assembly 'ClassLibrary1' or one of its dependencies. An attempt was made to load a program with an incorrect format.]
   System.Reflection.RuntimeAssembly._nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, RuntimeAssembly locationHint, StackCrawlMark& stackMark, IntPtr pPrivHostBinder, Boolean throwOnFileNotFound, Boolean forIntrospection, Boolean suppressSecurityChecks) +0
   System.Reflection.RuntimeAssembly.InternalLoadAssemblyName(AssemblyName assemblyRef, Evidence assemblySecurity, RuntimeAssembly reqAssembly, StackCrawlMark& stackMark, IntPtr pPrivHostBinder, Boolean throwOnFileNotFound, Boolean forIntrospection, Boolean suppressSecurityChecks) +232
   System.Reflection.RuntimeAssembly.InternalLoad(String assemblyString, Evidence assemblySecurity, StackCrawlMark& stackMark, IntPtr pPrivHostBinder, Boolean forIntrospection) +113
   System.Reflection.RuntimeAssembly.InternalLoad(String assemblyString, Evidence assemblySecurity, StackCrawlMark& stackMark, Boolean forIntrospection) +23
   System.Reflection.Assembly.Load(String assemblyString) +35
   System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName, Boolean starDirective) +49

[ConfigurationErrorsException: Could not load file or assembly 'ClassLibrary1' or one of its dependencies. An attempt was made to load a program with an incorrect format.]
   System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName, Boolean starDirective) +762
   System.Web.Configuration.CompilationSection.LoadAllAssembliesFromAppDomainBinDirectory() +259
   System.Web.Configuration.CompilationSection.LoadAssembly(AssemblyInfo ai) +167
   System.Web.Compilation.BuildManager.GetReferencedAssemblies(CompilationSection compConfig) +238
   System.Web.Compilation.BuildManager.GetPreStartInitMethodsFromReferencedAssemblies() +78
   System.Web.Compilation.BuildManager.CallPreStartInitMethods(String preStartInitListPath, Boolean& isRefAssemblyLoaded) +334
   System.Web.Compilation.BuildManager.ExecutePreAppStart() +178
   System.Web.Hosting.HostingEnvironment.Initialize(ApplicationManager appManager, IApplicationHost appHost, IConfigMapPathFactory configMapPathFactory, HostingEnvironmentParameters hostingParameters, PolicyLevel policyLevel, Exception appDomainCreationException) +746

[HttpException (0x80004005): Could not load file or assembly 'ClassLibrary1' or one of its dependencies. An attempt was made to load a program with an incorrect format.]
   System.Web.HttpRuntime.FirstRequestInit(HttpContext context) +552
   System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context) +122
   System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr, HttpContext context) +737