Best practices for copying DLLs with DllImport in Visual Studio? - c#

I have a solution which contains 2 projects. One is a C++ wrapper for an external, third party library which is contained withing a series of Dll fies. The other is a C# project which references the C++ project via [DllImportAttribute].
What is the proper way to copy these Dlls so that they are found upon execution of the C# project? Are the typically registered with the system? Are all Dlls (both the external library and the C++ project) copied into the C# output folder?
How is this usually done? In a post-build step?
I'm sure there are a few ways to accomplish this, I just want to use the most common, trouble free approach. thanks.

Generally Windows searches a dll in the same directory of the executable file first:
https://learn.microsoft.com/en-us/windows/win32/dlls/dynamic-link-library-search-order
, so copy every dll files into this directory (the C# output folder in the case).

Based on your description, you want to call c++ dll in c# app.
I write the detailed steps in the following link, you could have a look.
how to call c++ dll in c# app

Related

Using C# library in another directory from C++ application

I have a class, written in C#, shared between a C# and a C++ application.
To use it in the C++ app, I wrote a CLI wrapper class.
Simple diagram:
C++ App ---accesses---> CLI Library ---accesses---> C# library
Unfortunately, because of some name conflicts beyond my control, the C# and C+ applications need to be in separate directories.
What options are there for having my C++ app access these libraries in another directory?
Can I use AfxLoadLibrary in my C++ app to load the CLI library? In that case,
would the CLI dll and the C# dll have to be in the same directory?
Can I have the managed CLI library load the C# library dynamically?
Are there any other options that I'm missing?
Another option:
Add a yourapp.exe.config file to your exe folder, listing one or more subfolders as probing paths. Put the files for each library assembly into one of the subfolders. You can put all assemblies (except the application assembly) into one folder if you want.

How to embed a DLL within a C# compiled application

I made a c# dll.but if the user want to use it in c# winforms he/she must have dll file in the exe folder.how can i do something with dll project that it automatically add dll to exe file when used in other winforms app?
is it possible?sorry if my english is not good
tnx
there are many ways.
here is a full guide:
http://msdn.microsoft.com/en-us/library/yx7xezcf(v=vs.110).aspx
I love this way to do this in code personally:
How to add folder to assembly search path at runtime in .NET?
You can save the dll in the Global Assembly cache.
Then you can refer to it in the application without needing it to be in the same folder.
http://support.microsoft.com/kb/837908
I think what you are getting at is the programmer wants to use a DLL you have provided, but does not want the DLL to be inside the same folder as the EXE file when compiled.
try this:
Embedding DLLs in a compiled executable
Yoy can embed / include DLL files inside the exe file
The key words here is Embedded DLL

Cascade copy of native dll resource through several projects in VS 2010

Hello I have a Project Solution consisting of several smaller projects. Those projects have dependencies to some others in the following way:
(1) Native unmanaged C++ dll with device control functions
Is used by…
(2) C# Project wrapping native functions to .Net
Is used by…
(3) Adapter wrapping to the special device to a more generally abstraction layer defined by a framework
Is used by…
(4) A simple example implementation tries to use this native device interface through the abstraction framework
Now the Problem: The native dll (1) is added to the .Net wrapper project (2) as "existing item" with "build event = content" and "copy to output… = always" as "Hans Passant" set it in this problem solution. The native dll is used in this wrapper via DllImportAttribute. And this works fine for this project. The dll will be copied to the output directory and can be found by the wrapper.
The wrapper (2) is used as "Reference" from the adapter-wrapper project (3) and also there the native dll (1) is copied to the output directory and can be found and used by the .Net wrapper (2).
BUT…
.. when I than add the adapter-wrapper project (3) to the simple example project (4) as an "Reference" the native dll (1) will not be copied to the output directory of this example project (4). So the dlls will not be found by the .Net wrapper (2) and cause a System.DllNotFoundException.
My question is: How can I make this work, that when I add the adapter-wrapper project (3) to another project, all dlls that are necessary and are in the output-directory (including the native dll (1)), are copied to the referencing projects output directory? And this without adding the native dll as resource to the example implementation as Marc Gravell saying.
Thanks a lot, J
Maybe I'm missing something, but what about changing the Output Path for each of the projects to build to a common "bin" folder?

How to include dotfuscated dll file to my c#.net project?

I have successfully dotfuscated my .dll file to prevent it from being easily read when decompiled...But the problem is, I can't use the dotfuscated dll file because my project can't seem to understand the contents of the file... Could anyone help me please?...
You need to run the obfuscator on the final output (all of the projects together) so that it can handle references across assemblies.
Until that particular dll is obfuscated with option to be used as external library, you cannot reference it within your project.
Few obfuscator, obfuscate all the public classes & methods, hence referencing them is not useful.

C# / C++ in same solution - DllImport not finding DLL

I have a solution with a C++ dll project and a C# project that uses it. The problem is that the build path of the c++ project is in the solution folder and the c# is in the project's bin folder (each nested with debug/release), so the DllImport doesn't find them.
Is there a standard way to fix this?
The way you are supposed to do this is to set the build path for both projects to the same 'bin' directory... preferrably one for the solution, not a project. Then just make all projects build to that one folder. You can change that from the Project settings.
Another technique is to use a post-build step for the C++ app that copies the DLL to the C# project's folder. That way you don't actually change any paths. You just copy over a DLL. Be careful here though because when you clean the C++ file's project, you may actually still have the copy in the C# projec'ts bin directory leaving you scratching your head as to why things aren't happening as expected.
Alternately, you can deploy the C++ DLL to a system path (also as part of a post-build step) but you'll have the same issues as stated above.
For debugging, I'd recommend these in the order presented.

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