compile dll with external cs file dependency - c#

I am trying to share my code's capabilities with another person, while obfuscating the actual code (via dll). However, my library depends on a (free) 3rd party piece of code that cannot be distributed in my package due to licensing, but both of us have - let's call it "sharedfile.cs"
Question: Is it possible for me to create a DLL of my code that depends on the existence of "sharedfile.cs", while not rolling that file into my dll?
If not... what options would be available? Both of us have "sharedfile.cs" but I do not want to expose my raw code by not creating a DLL.
Thanks a lot for any help!

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Inject a C# file in a DLL

I have a DLL written in C# for which I don't have the sources. I have tried different C# decompiler to modify the DLL, but they all give me errors in my attempts to recompile with the modifications, I suppose due to IL decompilation limitations. Is it possible to add a .cs file to the root of the DLL in order or inject a method to add a functionality ?
PS: This is not intended to hack a software but to create a mod of a game which requires DLL modification.
Your best approach may be to just create a wrapper project around the dll to add the functionality that you want. Your code could them reference the project instead of the dll. As long as the classes aren't sealed you should be able to inherit from them.
Modifying code you don't have access to probably isn't a good idea to begin with. Especially if the dll could be updated in the future.
You can also create a new DLL with the same namespace. This might make things look as if they're in the same location, but it's not the best practice and it could be confusing since namespaces are expected to match the project/dll name.
Benjamin's solution with the wrapper seems reasonable.
The Reflexil plugin for .NET Reflector could inject a method or a class in a DLL as illustrate in a video by its creator.
It prevents decompilation-compilation errors as it just injects IL code in the assembly.
To install this plugin follow these steps.

how to explicitly link a cpp/cli file to a c# library .dll?

I have a c++/CLI library that is in turn calling a c# library. That is fine, it is linking implicitly and all is good with the world. But for various reasons the libraries are not getting quite the prefect treatment by our automated build process, and the libraries are not finding each other unless we move the libraries to locations that we would rather not have them in, and would rather not fold into our build process.
It is suggested to me that we/I could write a post-build event that uses XCOPY. but lets say we don't want to do that.
Another suggestion is to explicitly load the dll. Windows says that to link explicitly "Applications must make a function call to explicitly load the DLL at run time." The problem is that Microsoft's example is not enough for my small mind to understand how to proceed with this idea. Worse, the only example I could find is out of date. Perhaps I am not using the right search terms but I am having difficulty finding more about it with google.
How do we explicitly Link a c++/Cli Library to a C# .dll?
----edit
OK, How do we explicitly Link a C++/CLI code, which exports a library using __declspec(), to a C# .dll.
There is no such thing as a "C++/CLI library", only assemblies are supported. There is no explicit or implicit linking, binding always happens at runtime. Assemblies are found at runtime by the CLR, the rules it uses to locate them are described in detail in the MSDN library.
Copying all dependencies into the same directory as the EXE is the sane way to go about it while you are developing the code. Well supported by build system, the C# and C++ rules are however different. C++ projects build to the solution's Debug directory, C# projects build to the EXE project's bin\Debug directory. So yes, altering a C++ project's Output Directory setting or copying files with a post build event is usually required to get everything together.

How can C# use a legacy DLL simply without registration(regsvr32)

Situation
I run a build system that executes many builds for many project. To avoid one build impacting another we lock down the build user to only its workspace. Builds run as a non privileged users who only have write ability to the workspace.
Challenge
During our new build we need to use a legacy 3rdparty DLL that exposes its interface through COM. The dev team wants to register the build(regsrv32.exe) but our build security regime blocks this activity. If we relax the regime then the 3rdparty DLL will impact other builds and if I have two build which need two different versions I may have the wrong build compile against the wrong version (a very real possibility).
Question
Are there any other options besides registration to handle legacy DLLs which expose their interface via COM?
Thanks for the help
Peter
For my original answer to a similar question see: TFS Build server and COM references - does this work?
A good way to compile .NET code that references COM components without the COM components being registered on the build server is to use the COMFileReference reference item in your project/build files instead of COMReference. A COMFileReference item looks like this:
<ItemGroup>
<COMFileReference Include="MyComLibrary.dll">
<EmbedInteropTypes>True</EmbedInteropTypes>
</COMFileReference>
</ItemGroup>
Since Visual Studio provides no designer support for COMFileReference, you must edit the project/build file by hand.
During a build, MSBuild extracts the type library information from the COM DLL and creates an interop assembly that can be either standalone or embedded in the calling .NET assembly.
Each COMFileReference item can also have a WrapperTool attribute but the default seemed to work for me just fine. The EmbedInteropTypes attribute is not documented as being applicable to COMFileReference, but it seems to work as intended.
See https://learn.microsoft.com/en-ca/visualstudio/msbuild/common-msbuild-project-items#comfilereference for a little more detail. This MSBuild item has been available since .NET 3.5.
It's a shame that no-one seems to know anything about this technique, which to me seems simpler than the alternatives. It's actually not surprising since I could only find just the one above reference to it on-line. I myself discovered this technique by digging into MSBuild's Microsoft.Common.targets file.
There's a walkthrough on registration-free COM here:
http://msdn.microsoft.com/en-us/library/ms973913.aspx
And excruciating detail here:
http://msdn.microsoft.com/en-us/library/aa376414
(the root of that document is actually here: http://msdn.microsoft.com/en-us/library/dd408052 )
Also, for building in general, you should be able to use Tlbimp or tlbexp to create a TLB file that you can use for building, assuming the point of registering is just to be able to compile successfully, and not to run specific tests.
Installation tools such as Installshield can extract the COM interfaces from the DLLs and add them to the registry. It can also use the self-registration process of the DLL (which I believe is what regsvr does), but this is not a Microsoft installer best practice.
in .NET COM is normally done thru Interop in order to register .DLL in .NET they are called Assemblies and that can be done several ways.. by adding references via VS IDE at the project level, or writing code that Loads and unloads the assembly.. by .Config file that haas the reference to the assembly as well as the using of that reference within the project... GAC.
If you have access to the 3rd party .DLL's you can GAC them, and reference them in your project
you can add a using to your .cs file header as well as add the reference to the project by right clicking on reference --> add Reference ...
you can also do the above step as well as set the copy local = true in the properties for that .dll.. I hope that this gives you some ideas.. keep in mind that .NET assemblies are Managed code so there are several ways to Consume those 3rd party .DLL's using other methods within C# like LoadFromAssembly ect..
Thanks for all the help.
We changed from early-binding to late-binding because we never really needed the DLL at compile time. This pushed the registration requirement from the build server to the integration test server (where we execute the installer which handles the registration). We try to keep the build system pristine and have easy-to-reset integration systems.
Thanks again
Peter

Merging dlls from dlls working under licensing

I will appreciate your help in this. I have spent many time in looking for a procedure or tool that can let me create a single DLL from other private dlls (I named private because these dlls are working under licensing). I already bought the lic but I dont like to see the vendors name in my apps (I'd prefer to see the dlls as MyDll.dll rather than Microsoft.dll)
I have used the Gilma and the ILMerger tool that Microsoft has in its website without results. So do you guys know how to create this dll?
Thanks,
Mark
Tools like ILMerge will merge managed assemblies. However, you may have problems doing this with 3rd party dlls as they will most likely be code-signed with a certificate and obfuscated to stop people tampering with them in any way.
Another approach would be to embed the 3rd party dlls as file Resources. You can then load them with Assembly.Load using a Stream created directly from your resources (GetManifestResourceStream), so the user will never see them as separate files on disk, but you won't actually be attempting to change their contents.

Linking statically in C#

I'm working on a module for a CMS. This module is distributed as a class library DLL.
I have several utility libraries I'd like to use in this module. Is there anyway I can link these libraries statically so I won't have to distribute several DLL's (thereby distributing my utility libraries separately)?
I would like to have only one DLL.
You can merge your many DLLs with ILMERGE:
http://research.microsoft.com/~mbarnett/ILMerge.aspx
Haven't tried it myself. Hope it helps.
Download here:
http://www.microsoft.com/downloads/details.aspx?familyid=22914587-B4AD-4EAE-87CF-B14AE6A939B0&displaylang=en
Brief Description (from download-page)
ILMerge is a utility for merging multiple .NET assemblies into a single .NET assembly. It works on executables and DLLs alike and comes with several options for controlling the processing and format of the output. See the accompanying documentation for details.
If you don't want to use ILMerge, see this page:
http://blogs.msdn.com/b/microsoft_press/archive/2010/02/03/jeffrey-richter-excerpt-2-from-clr-via-c-third-edition.aspx
editor's note: Jeffrey Richter advices to put your dlls into exe file as resources (For each DLL file you add, display its properties and change its “Build Action” to “Embedded Resource.”). Then a custom class loader is needed to make the executable work (At runtime, the CLR won’t be able to find the dependent DLL assemblies, which is a problem. To fix this, when your application initializes, register a callback method with the AppDomain’s ResolveAssembly event).
Be sure to change the resourceName string to point to your actual resources. (e.g. change AssemblyLoadingAndReflection to your project name.)
The short answer for this is no!
You can not link in a dll during compilation.
I don't know if there is some subtle way to do this, but you would probably have to distribute the dlls along with your cms.
The best way to do this is to make some kind of re-distributable.

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