Adding a dll file to a C# project - c#

It's a beginners question, but...
Image of dll reference and dll included in project file http://a3.vox.com/6a00c2251e5b66549d00e398ca81eb0003-pi
If you look at the image above, there is the "Bass.Net" dll added as reference and also directly as file in the project.
Can someone tell me what's the point of doing that?

No reason, really. It could be that Visual Studio is set to display files not in the project (hard to tell from the picture) and the dll's happen to be in the main directory. The text is pretty clear that the extra files are
bass.dll
bassenc.dll
lame.exe
The .net one happens to be with the others in the same directory and you need to add it as a reference.

Within Windows, a DLL is a dynamic link library, which packages a set of programmatic functionality together. In this example, bass.dll exposes the features and functionality relevant to audio processing through this file (and any files it depends on). In order to use this functionality, you need the reference in the solution, so that Visual Studio can link it at compile time. The DLL will then typically be copied to your output directory when the application is built.
That's all that is necessary to get the code to work properly, the rest is really just preference or convention. Some people prefer to have all the files that exist in the project directory in the solution, so that the Solution Explorer reflects the file system. Typically you will want to have libraries your application depends on somewhere in your solution directory hierarchy so that the entire application is packaged together (making source code control use easier, for instance). You won't want to put this library in the BIN directory or any directory that Visual Studio generates, though, to avoid accidental deletions. In any event, having the reference is the important part, the file being in the project or solution is not necessary.
Typically, you'll want to keep external libraries out of your source directories, though, so I wouldn't actually recommend this structure. I tend to use a structure like this, but, again, this is all preference:
Source: Source code and project files
Libraries: DLLs
Support: Miscellaneous code or projects, but not actually part of the application (perhaps deployment scripts)

Having those in your project and output directory allows the final executing code to reference them without any issues running on different machines.
It sounds as it they put the reference dlls in the project directory, reference them from there, and also include them in the project. That way, when the project directory is copied, the reference dll will be copied with it. Additionally, if the reference dll is missing, the project will complain in Visual Studio.

If an assembly (Bass.Net.dll in your case) contains classes you want to use, you must add a reference to that assembly to your project.

No point the best thing to do is get all your dependenicies and store them in a seperate folder and only reference them do not copy them to your solution ;)

It's really hard to guess why someone else did something, but if I really had to guess, I'ld say that the guy thought to embed the necessary dlls as resources to be sure it was availale to the application. I have seen this technique used to embed fonts or sounds and am not sure if it works at all with dlls; but it's just a guess.
Of course the best way to be sure the files were available would have been to create a deployment project, with Visual Studio or some other installation tool loke Wise or InnoSetup, just to name a few.

This actually might be a good idea in a lot of circumstances. In my opinion their are 3 types of dependencies
Assemblies from the .Net standard library. Never include those locally.
Assemblies that you expect other developers to install as part of an MSI or exe setup package. This usually means their strongly signed and have a copy in the GAC.
Assemblies that you don't expect other developers to install via an MSI or exe installer. Maybe because you have a third party or in house library not in the GAC.
In the third case, the simplest thing to do is store a copy of the DLL in the source repo.

Related

Why my WPF program cannot run without Visual Studio?

I made a WPF program which uses SQLite. And by using Visual Studio 2012, it generates both Debug and Release version exe file. When I go to Debug or Release directory and run my exe file, e.g. MultiStart.exe, it can run normally.
But if I copy the MultiStart.exe to my Desktop and try to run it, it failed.
By several tests, I found that I also need to copy files MultiStart.exe.config and System.Data.SQLite.dll to my Desktop. And then it can run now.
But why? Do we have better solution so that I can make it run without addition files?
Thanks!
Why my WPF program cannot run without Visual Studio?
The question title is not really accurate since it's not really related Visual Studio. MultiStart.exe is dependent on configuration (MultiStart.exe.config) as well as other assemblies (System.Data.SQLite.dll). Without these dependencies the application cannot run (because that is how .NET works).
WPF doesn't necessarily need a config file to run so the question is what is in your config file that the application needs. It might be possible to move this configuration information into the code (e.g. connection string) and remove the app.config but then the values will be hard coded in the application.
In terms of dependent assemblies, instead of deploying them it is possible to embed them as resources and then use the AppDomain.AssemblyResolve Event to read the assembly from a resource (see Embedding assemblies inside another assembly for an example).
Another approach instead of embedding assemblies as resources is to merge them into one assembly. ILMerge is a popular choice for merging assemblies but I read that it can have issues with WPF assemblies (not sure if that applies to you). See Merging dlls into a single .exe with wpf for some other ideas for merging assemblies with WPF.
Note that setting PATH variables does not work because .NET does not use the PATH for resolving assemblies -- see How the Runtime Locates Assemblies for the details.
Another, option instead of copying the MultiStart.exe to the desktop is to use a shortcut on the desktop that links to the appropriate directory. Perhaps that is a simpler solution
You can also use ILMerge to merge all dependencies into single .exe file to simplify distributiuon of your application.
More detaiils on ILMerge can be found here: ILMerge on CodeProject
Example of usage: ilmerge /target:winexe /out:YourDestinationApp.exe
YourCurrentProgram.exe System.Data.SQLite.dll
Better solution that i used to do with my windows form apps is, Copy the entire folder, which contains supporting files. place it where you want. then create a shortcut of your .exe on your desktop. That always worked for me.
Because you are missing some dependency. You can open your config file and set the dependency...but I wouldn't recommend you to change config file manually.
You can also copy the dependent dll in system32 folder. ..but its only a trick because exe first search dlls in current folder than system 32 folder.
Because you're missing things from your PATH. Visual Studio is probably set to copy DLLs to the target directory on build.
You're almost certainly pulling in external libraries. Some of these are part of .NET, while others are packaged in libraries in specific folders. When you start your exe, it looks in your PATH and the current folder for everything (which includes all DLLs Visual Studio copied).
When you moved the exe to the desktop, suddenly it had no idea where those DLLs are. You haven't specifically added them to your PATH, and they are no longer in the current folder. This is why copying those DLLs to your desktop magically made them work.
Unless you stop use SQLite, there is not a way for you to not need that DLL (there are lots of ways to package/reference it though).

Why does VS2010 allow for the concept of "include in project"?

I'm still learning the basics of how VS2010 sees the world. Apparently, you can optionally "include" a file in a project. I'm a bit confused by this: If a file is version-controlled, AND the file is within the project directory, shouldn't it implicitly be "included" in the project? If not, what's the use case where a version-controlled file in the project directory should NOT be included in the project?
=== Addition ===
Based on the answers I've gotten so far, maybe I should rephrased my question: What does it mean for a file to be "included" in a project?
A project needs to know about files in order for compilation and distribution to occur. Just because you have a file that's under source-control, doesn't mean that it will be compiled if the project is unaware of it.
Also, you may want to include files as part of a distribution package. We do this quite often for our web projects that we distribute using web app gallery.
Conversely, you could have documentation or sql scripts that you version control, but do not want them to be part of the project.
EDIT: In answer to your update, what it means for a file to be included in a project is that the file is actually added to the .csproj or .vbproj file and will be used during compilation and/or distribution. VS does differentiate if the file is Content or if it needs to Compile it. This can be seen by clicking on the file in Solution Explorer and looking at the Build Action property.
No, you don't want random files that happen to be in the project directory included in source control.
We do sometimes put documentation (pdfs) or drawings/schematics in the project folder and under version control but you don't need them inside the visual studio project (especially when they are not being distributed because they are for internal use only).
Excluding the file from your project can be useful if the file is related to the project but not necessarily needed in the solution.
Example
If I need some test XML for an application that i'm writing; that is designed to normally be pulling this from a WCF service, it can be useful to keep that file in the directory for a development environment where I use IO to get the XML for testing, but I don't necessarily want it in my solution which is source controlled.
When you exclude a file from a project is no longer compiled or embedded, then when you want to include it again you can do so without having lost your settings.
If you e.g. copy a file (containing a helpful class which want to have in your project) into a folder of your project, then you will see ... nothing. You have to check the option "Show all files" of the solution explorer and the copied file can be seen, but it is still "greyed out". No you can choose the menuitem Include in project and that file will be integrated in your project and a pending change (add) for your source control is added too. Visual Studio doesn't include all files it can find in the project folder automatically to the project - and that is a good feature.
One of my colleagues explained to me a scenario in which a version-controlled file should NOT be part of the project. Here's the idea:
A developer writes some new code.
The code is experimental, and not intended to be part of the normal build.
The easiest way to exclude the file from the build is to NOT include it in the project, but still version-control it.
This way, the file can be shared with other developers, but not break the build.

Possible to package all needed files in an EXE?

I wrote an EXE that uses a third party dll and a template excel document. Anytime someone uses it they have to copy all three files (which is a pain).
Is there any way I can package everything that is needed into the EXE so there is only one file to worry about?
This is something that ilmerge is used for, atleast for combining assemblies. There is more information here and here.
There are several known problems with this though.
Yes - drag it into your project resources (My Project > Resources tab) and from there you can access it using global::Resources.resourceFile (I think - that might not be the right syntax, an alternative is here) as a byte stream and write it locally from there.
You can add files to your project in visual studio and set Build Action to None and Copy to Output directory to Copy always.
or
You can add these files to assembly resources. Adding and Editing Resources (Visual C#)
I suggest doing the first.
Also, for 3rd party dll: set Copy Local to true for the reference.
After you have your project set like this. Create setup project in VS and it will make one exe as you want.
How to: Create or Add a Setup Project
Software installation is a pain, but I think you can get away with an xcopy style deployment by using the compression tool of your choice (like winzip) and creating a self extracting executable.

VS2010 Building Solution - Add Files to BIN folder

We have a solution comprising of a windows application and various library files. Not all of the library files are referenced by the main windows application however we would like to have all the library files included in the output build folder "bin".
Obviously one solution is to simply reference every single library from the Windows application however we would like to avoid any unnecessary referencing.
How can we include additional files into our build folder?
This is a C# project.
You can always use the pre-build or post-build events in the project settings to copy the additional files.
You can do this simply by doing a bunch of copy source target, or you could even be fancy and write an nmake file. You do have to maintain the list of source files however...
Edit:
One other thought. Your assumption is that this is "unnecessary referencing". However, if your application depends on these assemblies to run, whether or not they are compile time references, then don't these dependencies become "necessary" references? In that case, isn't adding them as references and letting Studio's build system work for you the best (and simplest) approach?
The solution was to change the build location for all "libraries" within the solution to the main output "bin" location. The main Windows application only references the libraries that it depends upon however all the libraries are built to the one "common" location.
Thanks to Nader Shirazie for help with this question.

System.Addin & ClickOnce

I have a annoying build process from using System.Addins API with ClickOnce. Using System.Addins requires a specific directory structure, and the main project does not reference the adapters, view, and contract directly, which doesn't work well with the ClickOnce architechture.
The annoying part with the build process is that I have to copy, via post build event, the .dlls from the add-in components into the directory of the main app project, then reference those files manually from the main project, so that ClickOnce will include them. Firstly, this takes 2 iterations of build to get it to build correctly, secondly, it interferes with source control (I have to exclude the copied add-in dll files from source control or any changes made to them would require checkout).
So, my question is, is there a way around this hack? Something more elegant?
I can't fully answer your question, but it appears you are creating ClickOnce deployments through Visual Studio. I would ditch that method and use MageUI instead. It's a stand-alone executable that can be found in the framework SDK that will generate your application and deployment manifest files. It comes with a gui version (mageui.exe) and a command line version (mage.exe).
Mage may not get rid of your post-build event but it should do away with having to reference the files to get ClickOnce to see them.
Thanks for your input, I am currently doing it the way you mentioned; creating the folder in my project, and include the dlls that I need. It works, but it's an ugly solution, and it interferes with Source Control.
I'm aware of the limitations of ClickOnce, I was hoping there may be a way around it. For example, I read somewhere that I can use deployment projects to create the appropriate dependencies needed in a specific structure. The problem with that is once it is deployed to the public, there is no easy way (within ClickOnce) to update those dependencies.
The solution I use is to have a single output folder for all projects. Every project puts it's own files in the correct subfolder. The application bootstrapper project puts his dlls also in the output (root) folder. When you then create a click-ones for the bootstrapper, it will take all the content from the output folder.
The hardest part is to actually get all the dll's in the right place (and have every dll only once)
I solved this problem by adding the pipeline assemblies as content into the main solution structure.
To do this, change the output folder from (/bin/debug /bin/Release) to something else. I used ../lib otherwise you would get a visual studio cannot reference this file error.
Create the pipeline folders in your main solution
\AddInSideAdapters
\AddInViews
\Contracts
\HostSideAdapters
Right click on each of the folders and click "add existing item" change to view all files and then browse to your ../lib (or wherever you have the output set) and then pull down the add button (click the down arrow) and click "Add as a Link".
Right click on each file and set it to Content.
This will create a refresh file pointed to your assemblies and they will be included into the clickonce manifest.
ClickOnce do not let you install the software where you want. It will install the binary and dlls in the documents and settings. You can in your project properties go in the Publish tab and select Application Files to select additional file to Include. If the System.Addings require dll in a specific folder relatively to your assembly, you might just create the folder in you project and includes from here the dlls. This might works. If not, I do not have "hack" or other solution, clickonce is great but limited with some functionalities.

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