Develop Reference

Could not load file or assembly (DarkRift)

I've been struggling with a problem in Unity and I would appreciate it if anyone can help me.
I'm using a package called DarkRift, which is used for networking and connecting clients with a server (provided by DarkRift). In order to work with the DarkRift server, I need to write plugins. A plugin is basically a visual studio project, compiled to .dll file, then that file is copied to a certain directory on the server-side.
I've been working with DarkRift for some time now and have done so much with it. It was working perfectly! However, I needed to work with Firestore package from Google.
Hence, I created another plugin, installed Firestore (and every package needed), wrote some simple code using one of Firestore's functions, compiled the project, copied .dll to the server, then ran the server. The problem is whenever I run the server (.exe file), I get an error that says: "Could not load file or assembly 'Google.Cloud.Firestore, Version=1.0.0.0, ...' or one of its dependencies."
I get this error when I use any of Firestore's functions. However, if I just include the package (using Google.Cloud.Firestore;) without using any of its functions, I don't get any error. I googled this problem and looked everywhere and could not solve it.
Thanks!

Firestore is distributed as a Nuget package, which indeed has dependencies.
Have you also copied all those dependencies to the server?
It might also be a framework incompatibility.
To get more details about this kind of problem, you can register a logging event handler on AppDomain.AssemblyResolve, which fires when assembly resolution fails.
You can also use tools like dnSpy to dig into the problematic assembly - it shows you all sorts of metadata and it can decompile the CIL, which is invaluable for debugging strange behavior in third party code.
Assembly loading is kind of slow in .Net, so it only loads them when needed.
Hence the resolution does not fail when no code references the assembly.

Avoiding errors when loading DLLs

I am trying to use MEF, however, I noticed that it will crash if a .dll with the wrong interface is present in the directory that is being currently used. Is there any way to correct/avoid this issue, beyond simply only allowing the correct .dlls to be present in the plugin folder?
EDIT
Error is:
Unable to load one or more of the requested types. Retrieve the LoaderExceptions property for more information.

Identifying problematic dependencies in C++/CLI project

My application compiles fine, but I get the following runtime error:
System.IO.FileNotFoundException was unhandled
HResult=-2147024770
Message=Could not load file or assembly {Wrapper} or one of its dependencies. The specified module could not be found.
The reference to Wrapper in the calling Application looks correct. The Wrapper dll exists in the correct location.
This project used to build and run on someone else's system, I saw it demonstrated several times. That person/computer is no longer available. Some paths of some dependencies have changed since the last time it was successfully built and run, I have fixed all compile errors related to this.
Just to clarify my project structure:
Digraph G
{
App [ label = "My C# Application"]
Wrapper [ label = "C++/CLI Wrapper"]
Lib [ label = "C++ Library"]
Dll [ label = "My helper C# DLL"]
CDep [ label = "Series of deep C++ dependencies managed \n by CMake for Lib, hard coded relative paths for Wrapper."]
App->Wrapper->Lib->CDep;
App->Dll->Wrapper->CDep;
}
Wrapper is a C++/CLI wrapper around a C++ library. The error is triggered when we try to load a class in the Application that has a using statement for the Wrapper.
Wrapper does have a lot of dependencies, but the error message does not indicate which dependency is problematic. This is a large, complicated system, most of which is built by other teams. The C++ components use CMake to get all the dependencies correct, but CMake does not natively support C#.
I tried using fuslogvw to find the binding error, but it showed me absolutely nothing until I changed settings to include all binds, and then it only showed successful binds.
http://msdn.microsoft.com/en-us/library/e74a18c4(v=vs.100).aspx
The paths are long, but not over 256 characters.
I had a warning in the compile for Dll (see graph above):
Warning 1 There was a mismatch between the processor architecture of the project being built "MSIL" and the processor architecture of the reference "{cli_wrapper.dll}", "AMD64". This mismatch may cause runtime failures. Please consider changing the targeted processor architecture of your project through the Configuration Manager so as to align the processor architectures between your project and references, or take a dependency on references with a processor architecture that matches the targeted processor architecture of your project.
In Configuration Manager, the Dll is building for Platform "Any CPU" and Wrapper is building for "x64". I changed the dll to x64. I still get the runtime error.
Could not load file or assembly or one of its dependencies
Performed a clean, deleted build directory contents. No change.
Re-opened Visual Studio. No change.
Tried changing assembly name, default namespace, and project name to match. No change.
Could not load file or assembly 'xxx' or one of its dependencies. An attempt was made to load a program with an incorrect format
I believe we have to compile for 64 bit. We are dependant on a 64 bit C++ library.
Could not load file or assembly ... The parameter is incorrect
I am local administrator.
How to enable assembly bind failure logging (Fusion) in .NET
Tried the registry settings, but they appear to just be fuslogvw settings. No improvement in available log data.
Many other similar questions had ASP or service install specific answers.

I found the problem. There was more than one version of the library available to me, and I was using the include files from one version and the compiled library of the other. Dependancy Walker was key to finding which library had the problem, and if Aschratt had posted that as an answer rather than as a comment I would have accepted his answer.

I had the same error with a similar project earlier this week. First, when using C++/CLI, "Any CPU" doesn't exist. I had to build both for x86 to get through things.
Also, though my wrapper's dependencies were satisfied, it's the wrapper's exception that is caught by the CLR so it claims that the wrapper is missing a dependency. I was actually missing a dependency for the C++ DLL my wrapper wrapped (in my case, it was just a matter of forgetting to drop SDL2.dll and OpenAL32.dll in my new "Release" configuration output folder... I'd previously only worked with the Debug configuration where I'd already dropped those DLLs.
If you're positive you've got your wrapper's dependencies worked out, I'd recommend using Dependency Walker to check out the native DLL's dependencies. You could use Assembly.GetReferencedAssemblies with an outside script/program to double-check your wrapper as well (or ILSpy: http://ilspy.net/).
Last but not least, take a look at this: http://www.codeproject.com/Articles/442784/Best-gotchas-of-Cplusplus-CLI. He details the first two recommendations I made as well as some others.
Good luck!

One alternate root cause I've been running into quite a bit later, is that the application I'm working on uses impersonation, and the impersonated user does not have permissions to the GAC or to the folder that some dlls are in. You need to either give that user permissions, or change the way you do impersonation to load the dependencies before impersonation starts.

c# app can't find dll in its working directory

I just switched from C++ to C# and I am a bit confused about referencing DLLs.
I have a third party DLL and a simple testing application that uses some of its methods. When I compile the project, everything goes well, but when I run the compiled app on another computer, I've got an error that says that the DLL is missing even though the DLL is in the app's working directory. What's even more strange is that I have access to the source code of another app that is dependent on an older version of this DLL and this app works well.
I've gone through the code and all the solution settings without finding anything really different.
Can you tell me how to reference a .dll from a working dir (Visual Studio 2010)?
Below is the exception:
System.IO.FileNotFoundException was unhandled
Message=Could not load file or assembly 'TIS.Imaging.ICImagingControl32, Version=3.2.4.1146, Culture=neutral, PublicKeyToken=257805929e8b7928' or one of its dependencies. The system cannot find the file specified.
Source=ICtestapp
FileName=TIS.Imaging.ICImagingControl32, Version=3.2.4.1146, Culture=neutral, PublicKeyToken=257805929e8b7928
FusionLog=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].
StackTrace:
at ICtestapp.Form1.InitializeComponent()
at ICtestapp.Form1..ctor()
at ICtestapp.Program.Main()
InnerException:

Here's a good blog post from Suzanne Cook from the .net team on debugging .net loader issues.
http://blogs.msdn.com/b/suzcook/archive/2003/05/29/57120.aspx
and here's the details on how it loads:
http://msdn.microsoft.com/en-us/library/yx7xezcf(v=vs.71).aspx

You have to add the dll as reference in your project references, once you added the library in the reference, when you compile the program the dll will be automatically copied to the compilation output folder unless otherwise specified in the reference properties ...
Then if you copy all items that you will find in the compilation output folder in the new location in the other PC, you should not have any problems.
Check also that the .NET framework installed on the other machine is at least as the same level of the project target ..

This also happens when you copy the debug executables over to another machine. Try compiling in release and moving over.

PowerShell + SharePoint cannot seem to add an assembly

I am having an issue 'using' a custom field I have created. In power shell, the assembly is being loaded into the script using the LoadFrom function, and it throws no errors in loading the assembly, yet it acts as if the assembly wasn't loaded.
When trying to enumerate fields, I will get a 'not installed properly' error on one of my custom fields. When trying to access a custom field via myListItem["myCustomField"] I get a CannotIndex error.
I get these same errors when writing the exact code in Visual Studio with C#, however, once I add the reference to my assembly it works fine there. (Important part here, this should indicate that I am not doing anything incorrectly in power shell, i.e. accessing the field by its display name rather than internal name etc).
If I add my assembly to the GAC, everything works fine in power shell, but this is not an option for me at the moment. I need to be able to load the assembly from the dll.
Any clues?

An assembly loaded via LoadFrom does not behave the same way as one loaded from the GAC. It's more than just trust issues. If you have the patience, start here:
http://blogs.msdn.com/b/suzcook/archive/2003/05/29/choosing-a-binding-context.aspx
Adding a reference in visual studio is just for the compilation process, not the runtime loading. At runtime, the the dependent assemblies (references) are placed in the same directory as the process executable (if they were not GAC references.) In the powershell case, your dependent assemblies are not in the same location as the process executable (powershell.exe). This is why probing for their dependencies fails. If you copied them into $PSHOME it would probably work, but this is not a workable solution as this is a privileged location under system32.
-Oisin

PowerShell 2:
Add-Type -Path C:\Path\To\Assembly.dll
PowerShell 1:
[Reflection.Assembly]::LoadFrom('C:\Path\To\Assembly.dll')