Visual Studio C# .dll vs. project referencing - c#

I have two C# projects in my Visual Studio solution. Project B needs to reference code in Project A. Both projects need to be compiled to dll's and then used in an application.
In Project B I can set a reference to project A and that allows things to compile. But when I actually use the resulting dll's in my application it throws a missing assembly reference error.
My current solution is to tell Project B to reference the bin/debug/ProjectA.dll. Everything works when running the application with this configuration. But this solution has a number of problems. For instance, any code written in Project A that B relies on wont be visible to B until A has been rebuilt. And building the solution relies on A being built first.
Is there a way that I can add a reference to Project A but have the resulting dll built so it looks for the ProjectA.dll reference and not the project itself? I expect there is, but my google searching has resulted in no answers.

For instance, any code written in Project A that B relies on wont be visible to B until A has been rebuilt. And building the solution relies on A being built first.
This is not a problem, this is, in my view, a benefit. As you are guaranteed to not be able access functionality which is not there. In case of a new functionality, one may say, it's not a big deal: I can not find it, got an exception/error so I know something went wrong. But what about updated code ? In this way you are guaranteed that B will use only most updated version of A.
Is there a way that I can add a reference to ProjectA but have the resulting dll built so it looks for the ProjectA.dll reference and not the project itself?
You may simply implement post-build event on your project A which copies it and all dependent DLLs in some predefined central location, where B.dll will be copied too. If your B.dll depends on A.dll, OS, following default behavior, will search for A.dll in the same folder where B.dll is, for first, before checking %PATH% variable content.

Related

Add reference to local folder

I'm adding my dll file to my reference and set Copy local to true
Everything is OK and after I build application, my dll added to output folder
Now my question is how do Ι change the local path?
For example:
my application path is C:\myproject, I want to put dll into C:\myproject\libs
How can I set dll path to {applicatonpath}\libs NOT {applicationpath} ?
When you compile you project, visual studio will put everything that has been compiled and set to copy locally to the "output folder", which depends on your current compile configuration. If you are compiling in Debug mode then this folder will be:
c:\your_solution_path\your_project_path\bin\Debug
If you use Release mode, it will be:
c:\your_solution_path\your_project_path\bin\Release
However, sometimes we reference a lot of assemblies (DLLs if you will) and those assemblies have dependencies of their own. In order to make everything "point and click" for our convenience, we must tell visual studio how we would like it to act for a particular project build.
So, as TotPeRo said, you should go do project properties and use the functionality of Pre-build and Post-build events. As the name suggests, Pre-Build happens before the actual build, while Post-Build takes place immediately after it. Please refer these links for further information: link1 and link2.
Lets assume the following scenario:
You have one solution.
that solution holds 2 projects (let's call them Project A and Project B). Project A is the actual GUI. Project B is just a helper project, that compiles into a DLL.
Let's say, that project B is doing some heavy matrix calculations, so you also have to include some MatLab libraries. NOTE: only Project B uses these libraries.
Project A references project B so that you can use the calculated information from B and show it in gui in A.
In order to compile this, the compiler is smart enough to determine, that Project B should be compiled first. If everything checks, the project is compiled into ProjectB.dll. Then, the compiler proceeds to compile Project A. It check all the dependencies and finds out, that you have already compiled Project B (which is a dependency for Project A) and that it can continue. Everything is then copied to the output folder (bin/Debug or bin/release) and should be in working order.
However, during runtime, something goes wrong and the application crashes. You find out, that Project B does not have the appropriate library to work with (namely MatLab libraries). And then you conclude, that MatLab should be included in the bin/debug (or bin/release) folder at compile-time. Since the MatLab library is a dependency library for Project B but not for Project A, it does not get copied and hence the exception. You can mitigate this behavior with the aforementioned Pre and Post-Build events. You can tell the Visual Studio that you want it to manually copy MatLab.dll to the output folder when it is doing a compile. This comes super handy when you come into situations like these. Build events can also trigger a lot of other things so be sure to check it out. I'm using this a lot and it's a time saver at least.
in the Visual Studio you can go Project > [project name] Properties > Reference Path
change the path/create folder or else you want
First make folder lib new project source code then use relative address
in post-build event on visual studio go to properties in your project and add this:
copy "c:\pathtolibrary\bin\debug\namelibrary.dll" "$(SolutionDir)\bin\Debug\libs"

DLL reference not copying into project bin

Project A references Project B, and Project B references an external DDL (restored using NuGet). The DLL should get copied into Project A's bin folder (along with Project B's DLL):
In my case, when running Project A, I get the following exception thrown:
Could not load file or assembly 'PostSharp, Version=3.2.18.0,
Culture=neutral, PublicKeyToken=b13fd38b8f9c99d7' or one of its
dependencies. The system cannot find the file specified.
The DLL is not being copied into Project A's bin. All other external references from Project B are being copied across just fine, which is what is confusing for me.
Copy Local is set to true for all references involved. Example:
How do I do this?
Note: Using Visual Studio 2013.
The options that I found were to:
Add a reference to PostSharp in Project A.
Add dummy code in Project B so that the compiler would detect that the reference is being used.
Add a build event to force copy the DLL.
I don't like any of the above solutions. They are hacks in my opinion and will only make for a more unmaintainable solution in the long run.
I have fixed the problem by using a common output directory. This seems to be a recommended solution by many. I have also experienced much faster build times. See this Stackoverflow post.
When I ran into this problem it was because I changed a project's name, but did not change the assembly name - it was identical to the assembly name of another project in the solution.
I've added some dummy (unused) code on Project B, making reference to the DLL needed.
Thus, the compiler will guess that it must copy the DLL into project A output.

Difference Between DLL Reference's? And Uses?

Please any one explain this. This Question helps to understand common things
Question:
What is the difference between when you 'add DLL reference from one project to another project via Browse Option and Add DLL reference from Solution project to another project and copy-paste from one project to another project'?
I have found an answer on google
Answer:
Adding a project reference adds a local project's DLL to the project that references it, and every time the solution compiles, the updated DLL for that project gets copied to the other project. So when you go through the build process, if you have 5 projects, each one rebuilds its DLL, and copies that DLL to its references.
But:
I don't know what the process is and the difference when we copy-paste from one project to another project?
When you do copy paste from One project to another, the dependent project add its reference of the file that you have paste in the project solution directory
When you do copy paste the dll of one project to the other project's directory and then Add its reference by browsing to that directory where you have pasted your dll. Then VS only add its reference and copy that dll to its bin folder and show you (allows you) all the method and properties that it contains.
If you do any change in your source project solution like adding or modifying methods then the updated dll of that project is not available in your dependent project solution.
So VS still points to the old dll file just because of the reference you added. So whenever you made any change in your source project solution, you have to add the reference of the updated dll to your dependent solution every time.
In Second Case: When you add reference of your source project into your dependent project solution, VS always take the most recent updated dll from your source project into your dependent project. So in this way you don't need to add reference every time you compile the code or debug.
When you just reference a DLL by browsing to it, VS would copy it to the output directory of the dependent project.
Suppose afterwards that DLL is updated - there is no guaranty that VS would retake that updated DLL, and copy it again to the output directory of the dependent project - which mean, that even after you fixed some bugs in the other project, those bug would persist in the dependent project (because it is still using the previous version of that DLL).
When you add reference to other project in the solution, VS would always take the most recent and updated DLL outputted from that project.

vs2010 - reference .exe not working

I've got a project (project A)in vs2010 (c#) that I want to reference another project (.exe) (project B) that I created. Project A is a quick, down & dirty util that I will only use once but I need all the function calls and db calls from project B, so rather than cut, copy, pasting from one to another, I thought I could just reference project B in my references. I am able to point to the .exe and in code i can use it, but when I compile it, it complains about not being able to see it (the infamous "are you missing a using directive or assembly reference?" error).
Does anyone know how I can do this?
Most probably, also it's hard to say, you have .NET Framework version conflict. One of your projects has .NET Framework version which is not compatible with other.
Check in project properties of both of them the version of the framework.
Make them the same
Recompile both of them
and most probably the trouble will gone.
Hope this helps.
Make sure the namespace of classes you want to use from project A is included in the files in your project B in a using directive:
using projA.ExampleNamespace;
I have the same problem. When I first added the reference all worked fine. But some time later after a rebuild there were errors and the classes and namespaces of "project A" were not longer recognized. Removing and re-adding the reference solved the problem immediately (without rebuiling or anything). There were no errors in other code and all DLLs and EXEs were build correctly. Build Order and Build Dependency settings were also correct. Seems to be a strange bug in Visual Studio (I use 2013 Professional).
I also checked how the reference was set in csproj file. The csproj file didn't change at all after removing and re-adding the reference. Neither did the sln file.
Maybe it's some strange caching behavior. But as I used "Rebuild All" which cleans up temporary files imho, this shouldn't happen. Even restarting VS or the PC didn't help.

Problem referencing same libraries from multiple C# solutions

I have two C# solutions (let's say A and B). Both reference a common C# library, which is included in both solutions as a project reference. This project itself references (as a project, not DLL) another library (managed C++) which is ALSO referenced by the two top-level solutions.
Whenever one project builds successfully, the other says that the C++ library has changed and needs to be reloaded. When I do so, the C# library reference complains that it can't resolve a namespace from the C++ library. If I delete and re-add the reference to the C++ library in the C# library, the solution builds fine, but now the OTHER solution will have the same problem, and so on.
What am I doing wrong? I believe I should be able to have this sort of reference setup without problems.
Right click the Solution and select Properties. Then select '...Project Build Order'. I assume we want the C++ project to build first?
Check the Solution Properties/Common
Properties/Project Dependencies and
make sure all the Depends On are set
right.
Is there a possibility to move all the C++ project references to the common C# library? That way project A and B just need to reference the common project.

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