I've created a dll using managed C++. Now I'm trying to use it from C#. I've added the Object to project references. Object browser shows the object in the dll correcly, path to the dll in object browser corresponds to the actual path.
However, when I run the C# program it complains:
Unhandled Exception: System.IO.FileNotFoundException: The specified module could
not be found. (Exception from HRESULT: 0x8007007E)
Any idea what else have to be done?
Thanks.
I think that you're missing the other assemblies or dll's references by your managed C++ assembly.
Does your managed C++ assembly have an other dependencies, including unmanaged dlls? You'll see this error at runtime if your referenced assembly fails to load a dependency.
Are you running the application in release on a machine without VS installed?
I only ask because I ran into a similar problem here: Mixed Mode Library and CRT Dependencies - HELP
if you scroll down to my answer you can see what I did that helped me.
Check that the c++ assembly is present in the same folder as your c# program. It should be copied over automatically if the 'Copy Local' property is set to true (on the reference to the c++ dll in your c# app).
If the c++ dll is there, the most likely problem is that the c++ dll depends on another non-managed dll which cannot be found (i.e. c# will not copy these to your app folder because it does not know about unmanaged references). You can use DependencyWalker on the c++ dll to check for missing dependencies.
Another probable couse could be a problem with your MSVC runtime dlls. see if DependencyWalker complains about missing MSVCR*.dll, MSVCP*.dll etc... files.
Related
I had one C++ project written in MFC and some of the project are of DLL type. I wanted to use those dll in my C# code(using DllImport).
I tried to add as a reference but could not able to and getting an error. Do i need to copy those dll's in any of particular location? How my code is going to link those dll's?
You can't add a reference to a native DLL. In DllImport you just import the DLL at runtime so be careful with the path to the DLL if it is not in the same directory as your managed application.
A problem with C++-DLLs is, that the function names in that DLLs can be decorated so you have to find out that decorated name before using it.
I have an application written in C# which interfaces with some custom hardware using a vendor supplied .Net assembly. The .Net assembly in turn loads another DLL at run time. I can add the vendor supplied assembly to my project but when I run it, the vendor assembly complains that it can't load the required DLL. I can work around this for the moment by copying the DLL to the bin\Debug and bin\Release folder.
The problem is that I will need to distribute this application to clients at some point and they will not have this DLL in place. I can't see how I can make the solution require it; I can't add it as a reference since I get the error "A reference to foo.dll could not be added. Please make sure that the file is accessible, and that it is a valid assembly or COM component."
I can't convert the DLL to a .Net assembly using TlbExp, it gives an error "The module was expected to contain an assembly manifest."
I thought if I published the application via "click once" that I could declare the dependency there but I don't see any way for this either. I also tried adding it as a file resource but this didn't seem to help.
I can see other questions on SO relating to how to invoke functionality in an external DLL but in this case, I just need a way to bundle the DLL with the project.
Thanks.
Indicates that the attributed method is exposed by an unmanaged dynamic-link library (DLL)
The DllImportAttribute attribute provides the information needed to call a function exported from an unmanaged DLL. As a minimum requirement, you must supply the name of the DLL containing the entry point.
For further reference go here
Link to Review
You could add the dll as a resource, write it out as a byte[] to a file on loading, and do an Assembly.Load() at runtime for deployment.
You might have to use an AppDomain.AssemblyResolve Event to make sure the assembly resolves in case of multiple versions.
you could add both (all) of the dlls in your project as references and mark them as "copy local". That should do it unless the first DLL expects the second DLL in a specific place.
I have a asp.net application calling intermediate C# dll which will make a call to a legacy vb6 dll through COM. During the actual call I find an error in my logs from my vb6 dll:
"Could not load file or assembly, 'Generic_C#_DLL.DataAccess, Version=1.0.0.0, Culture=neutral, PublicKeyToken=f0c9890f55677d2' or one of its dependencies. The system cannot find the file specified"
Why is my vb6 COM dll trying to load some of my other C# dlls? Is it because the dll that is calling the vb6 COM dll also referencing the 'Generic_C#_DLL.DataAccess'?
I think I am referencing the vb6 dll correctly in the C# dll that is calling COM by having a reference to 'Interops.VB6dll' and I have properly registered the vb6 dll with regasm.exe...So as of now I am kind of clueless to why this is happening, does anyone have any advice?
We're going to need to see code to be able to best help with this. However, note that this also says "or one of its dependencies", which may indicate that there is another load failure preventing this one.
There are a few very useful tools for figuring out DLL loading problems:
Fuslogvw.exe (Assembly Binding Log Viewer)
Dependency Walker 2.2
Process Monitor v3.03
I'm getting a System.DllNotFoundException for a .dll which is in the same folder as the executable whenever my application attempts to use a function which exists in the DLL. The weird thing is that it is only occurring on one user's PC; it works fine on my dev PC and it works fine on one non-dev PC that I tried it on. Also, there are other DLLs in the folder which are being found and used correctly. The DLL in question is a native library which is referenced by my application via another DLL which is a c# wrapper for the native library.
My initial instinct is that there must be some other library being referenced by this DLL which doesn't exist on the problematic PC, but I cannot imagine what library this PC could be missing that the other non-dev PC has.
So my questions are this: is there a way to determine the dependencies of a given DLL file? Keep in mind that the DLL in question is a native library (i.e. not managed code), and I do not have access to it's source code. And if it turns out no dependency is missing, what else might cause such an issue?
For unmanaged dlls you can use Dependency Walker to find dependencies.
I would suggest using ILSpy to open the dll and view its dependencies first.
I am writing a small AOL IM application in C#. I have all the dlls that I need and I have been able to compile and run my app. However, when it runs I get an error that says
"Unable to load DLL 'acccore.dll': The specified module could not be found. (Exception from HRESULT: 0x8007007E)"
I understand that this means the acccore.dll file couldn't be found but I don't know why. I tried putting it in C:\Windows\System32 and it is also in the debug directory that is created when the project is build in Visual Studio. Can anyone tell me how to make my application know where this dll is located?
Thanks!
I did some research and it looks like acccore.dll is a COM DLL file. That means you need to run:
regsvr32.exe C:\Windows\System32\acccore.dll
This will register the COM DLL into the registry, you can then use that DLL in your .NET code. Check out the link:
http://64.12.130.129/forum?c=showthread&ThreadID=1173
So you will need to use P/Invoke to use the DLL (I guess the AOL SDK has some example code you can use).
is this dll an assembly?
If so then fuslogvw will show you where the CLR is looking for assemblies. Put it where .net is looking
.NET assemblies need to be in the directory of the application (or one of its subdirectories, especially if they represent a localized version of a different assembly), or in the GAC (global assembly cache.) If the DLL isn't in the same directory as the .EXE, then that's your problem. If it is and it still doesn't work, it means that the assembly doesn't match for some reason.
I used dependancywalker to find the dll I was missing that caused it to error. This was suggested by Taylor Leese in a comment.