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.
Related
Morning Ya'all,
I recently got in touch with dlls. At the moment the only way of using Classes from the dll (added as a reference) is by copying the dlls in the bin\debug folder. When I try to start the .EXE with the dlls in a seperate folder, it gives an error that VS could not find the dependency...
I heard about configuration data files and AssemblyResolve, but so far could not find pieces of code that fixed my issue nor I understood. I am programming in C# btw.
Thx for everyone sharing his thoughts on this topic.
Create a libs folder in your project, copy the dll's into the folder and reference them in the project from the libs folder. When you build, it will include the dll's along side your exe.
I have a solution with two projects:
C# console application (.NET Core 3.1)
and C++ Dynamic Library (.dll)
I need to call the C++ DLL from the C# project, using DllImport. When I provide the full path of the DLL, the application finds it. But I want to replace the path with a relative path, and I can't figure out how to do it.
First of all, make the C++ project a dependency of the C# project. This ensures that the C++ project will be built before the C# project if it's outdated. You can set the project dependencies in the solution settings.
Now that we ensured that the dll is always up to date, we have to somehow get it in the same directoy as the C# executable. We have two options:
a post build command to copy the dll to the output directory of the C# project, or
we set the output directory of both projects to the same directory.
Post build event
We can simply use a copy command. Go to C++ project settings > Build Events > Post-Build Event and copy the following command to to the Command Line field:
xcopy /y "$(OutDir)*.dll" "$(SolutionDir)MY_CSHARP_PROJECT_NAME\bin\$(Platform)\$(Configuration)"
Replace MY_CSHARP_PROJECT_NAME with the name of your C# project. I'm using the default paths here, depending on your solution you might have to tweak the paths a bit.
Shared build directory
I wouldn't recommend this one, because you can run into trouble with it.
Go to the Build tab in the project settings of your C# project.
At the top of the page select Debug as configuration.
At the bottom of the page change Output path to match the C++ output directory for Debug builds (this one is usually in the same folder as the solution file).
Repeat 2 and 3 but this time with Release instead of Debug.
I'm working on a C# project that is nearing release. As part of this, I have started building the project and testing it on another machine. This has revealed some odd problems. My biggest concern, though, is that my project is failing to run. I can do some basic things, but when I try to use my projects primary functionality it crashes. Using Visual Studio, I was able to determine the exception that was causing the crash.
Essentially, I'm getting a FileNotFoundException on the dll that contains most of my project's functional code. I'm not sure if I've made an error in adding the dll to my project, or if there's a problem in one of the files in the dll.
The dll was added as a reference using the Project -> Add Reerences feature of the user interface.
The dll contains three files which contain absolute file paths (these are for #import statements). Example follows.
#import "C:\Users\Me\Documents\Projects\MyProject\Delegates\bin\MyDelegate.tlb" raw_interfaces_only
My hang up is I'm not exactly sure what I'm doing wrong here. I suspect that those import statements are causing problems, but I'm not exactly sure how to fix them if they in fact are the problem. This is my first c#/c++ project so any help would be appreciated.
Adding the dll as a reference DOES NOT include the dll with your project--you are simply telling your project to use the library for your code. The dll will need to be installed on all computers that run your application, for your application to use the dll.
If the dll also uses three files (as you specified), then those files must also be included, and be installed in the expected path.
Presuming you have redistribution rights on the dll you mention, you can include the dll in your project. Be sure to set the "copy" property as "copy always" or "copy if newer" and change the reference to use the copy that ends up in you bin folder. Then you only need to be sure to include that dll and install it in the same folder as your application.
I have a library with both managed and unmanaged C#, C++ dll files. I want to reference it from F#. Where can I place the C#, C++ dll files? I can not place them in the application folder (I must have copy local = false) and it will be only me who will use the program. I have tried windows/system32, GAC using setup and adding PATH variable pointing to a folder with all the dll files but none of it seems to work.
Thanks for any hint
When building your application in Visual Studio, it looks for the references in all the default folders (depending on your OS, .NET Framework version and other things) but also in locations you specified in the project configuration. Right click on the project in Solution Explorer, click Properties and go to the Reference Paths tab. Add C:\MyDllFolder or anything.
If you do this in all your applications which are using that dll, you could just have it sitting there once.
You can specify dll locations MSDN : Specifying an Assembly's Location or maybe use something like
Assembly.LoadFrom
if you want dynamics.
I have a C# GUI application that references a Managed C++ project, which requires 7 native C++ DLLs. I'm looking for the cleanest method for copying these 7 DLLs to the final project output.
What works
Add all DLLs to the C# applications, specifying:
Build Action == "Content"
Copy To Output Directory == Copy Always"
This will make the base folder of the project a mess of DLLs in some cases, all of which are requirements of referenced projects, and not that project itself.
What does not work
Adding these DLLs to a folder named "Required DLLs" with the above settings. It copies it to a folder with the same name in the output, causing them to be in an incorrect location. I can't see a way to specify the output directory.
Embedded Resources: In C# P/Invoke, you can add DLLs you're referencing as embedded resources, and the DLLs are embedded inside your final library. I don't see this possibility in Managed C++, and I'm not even sure if it works with reference chains.
Adding the DLLs as content within the Managed C++ project. The files do not get copied to the output directory.
What is the best solution in this case? I'd prefer the Managed C++ project to be able to handle it's own DLL requirements if possible, and preferably in a way that won't prevent the project from being used across multiple applications.
As far as having a clean project goes, is it better to insert all my code files within subfolders in the project, and have the DLLs at the root to make the first solution work?
Solution:
Using the post-build suggestion from Joseph, the following command does the trick to use a "Required DLLs" folder.
xcopy "$(ProjectDir)Required DLLs*.*" "$(TargetDir)" /Q /Y
/Q hides the individual files from the output, and /Y suppresses overwrite prompts.
You can use a post-build event to copy the contents of a directory (e.g., your "Required DLLs" directory) into the project's output directory.
You can work with static libs instead of dynamic, it will make your dlls bigger but single dll instead of multiple is just time saver and not only in your aspect.
Route all the projects in the solution to a single directory (managed and unmanaged).