Could not load file or assembly 'DocumentDB.Sp

Question

We have 3 projects:

• Class Library (Target Framework 4.5)
• Web App (MVC) Project (Target Framework 4.5)
• Web API Project(Target Framework 4.5.2)

Recently started working with Azure Cosmos DB (Document DB driver). All the implementation is done in Class Library used in API & Web App projects both.

Apparently, Web App works fine but REST Api project throws an error:

Could not load file or assembly 'file:///API\bin\DocumentDB.Spatial.Sql.dll' or one of its dependencies. The module was expected to contain an assembly manifest.

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 'file:///D:\API\bin\DocumentDB.Spatial.Sql.dll' or one of its dependencies. The module was expected to contain an assembly manifest.

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 'file:///D:\API\bin\DocumentDB.Spatial.Sql.dll' could not be loaded.


WRN: Assembly binding logging is turned OFF.
To enable assembly bind failure logging, set the registry value [HKLM\Software\Microsoft\Fusion!EnableLog] (DWORD) to 1.
Note: There is some performance penalty associated with assembly bind failure logging.
To turn this feature off, remove the registry value [HKLM\Software\Microsoft\Fusion!EnableLog].

Stack Trace: 


[BadImageFormatException: Could not load file or assembly 'file:///D:\API\bin\DocumentDB.Spatial.Sql.dll' or one of its dependencies. The module was expected to contain an assembly manifest.]
   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.nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, RuntimeAssembly locationHint, StackCrawlMark& stackMark, IntPtr pPrivHostBinder, Boolean throwOnFileNotFound, Boolean forIntrospection, Boolean suppressSecurityChecks) +36
   System.Reflection.RuntimeAssembly.InternalLoadAssemblyName(AssemblyName assemblyRef, Evidence assemblySecurity, RuntimeAssembly reqAssembly, StackCrawlMark& stackMark, IntPtr pPrivHostBinder, Boolean throwOnFileNotFound, Boolean forIntrospection, Boolean suppressSecurityChecks) +152
   System.Reflection.RuntimeAssembly.InternalLoadFrom(String assemblyFile, Evidence securityEvidence, Byte[] hashValue, AssemblyHashAlgorithm hashAlgorithm, Boolean forIntrospection, Boolean suppressSecurityChecks, StackCrawlMark& stackMark) +102
   System.Reflection.Assembly.LoadFrom(String assemblyFile) +34
   WebActivator.PreApplicationStartCode.Start() in D:\Code\Bitbucket\WebActivator\WebActivator\PreApplicationStartCode.cs:11

[InvalidOperationException: The pre-application start initialization method Start on type WebActivator.PreApplicationStartCode threw an exception with the following error message: Could not load file or assembly 'file:///D:\API\bin\DocumentDB.Spatial.Sql.dll' or one of its dependencies. The module was expected to contain an assembly manifest..]
   System.Web.Compilation.BuildManager.InvokePreStartInitMethodsCore(ICollection`1 methods, Func`1 setHostingEnvironmentCultures) +613
   System.Web.Compilation.BuildManager.InvokePreStartInitMethods(ICollection`1 methods) +141
   System.Web.Compilation.BuildManager.CallPreStartInitMethods(String preStartInitListPath, Boolean& isRefAssemblyLoaded) +102
   System.Web.Compilation.BuildManager.ExecutePreAppStart() +157
   System.Web.Hosting.HostingEnvironment.Initialize(ApplicationManager appManager, IApplicationHost appHost, IConfigMapPathFactory configMapPathFactory, HostingEnvironmentParameters hostingParameters, PolicyLevel policyLevel, Exception appDomainCreationException) +531

[HttpException (0x80004005): The pre-application start initialization method Start on type WebActivator.PreApplicationStartCode threw an exception with the following error message: Could not load file or assembly 'file:///D:\API\bin\DocumentDB.Spatial.Sql.dll' or one of its dependencies. The module was expected to contain an assembly manifest..]
   System.Web.HttpRuntime.FirstRequestInit(HttpContext context) +9942412
   System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context) +90
   System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr, HttpContext context) +261

Now, have tried out the following fixes (with no success):

1. Changed the API Target Framework to 4.5, restarted - still the same error.
2. Clean the solution, rebuild - still same error
3. The dll DocumentDb.Spatial.Sql.dll is same in the Web App & Web API project.

Answer 1

I faced the same issue while integrating COSMOSDb in Web API project.
I was using AttributeRouting. One of the dependencies added by AttributeRouting is WebActivator.

When re-tried the same without using AttributeRouting (working with the default controller, API structure of WebApi project in VS 2017), things worked fine for me.
I found it was due WebActivator which I think need some more dependent DLLs to work with COSMOSDb.

Answer 2

Could not load file or assembly 'file:///API\bin\DocumentDB.Spatial.Sql.dll'

This path is suspicious. You must check which module is trying to load this dll (and why)

Try enabling assembly binding logging and check for errors while you load solution. To enable logging paste this to txt file (and change extension to .reg):

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Fusion]
"ForceLog"=dword:00000001
"LogFailures"=dword:00000001
"LogResourceBinds"=dword:00000001
"LogPath"="C:\\FusionLog"

After that, check folder C:\FusionLog and search for this dll DocumentDB.Spatial.Sql.dll)