I've been given a dll to talk to a device, I have little to no experience in C# and I'm supposed to get the device initialized by the end of the week. The dll has methods to open ports and send messages, but I have no idea how to get access to the functions
I know its a bit ridiculous to ask but im running out of time.
Thanks,
Add a Reference to the .dll file in your C# project.
Add a Using namespace at the top of whatever class is going to interact with the .dll methods.
You will now be able to access the methods.
Edit: If your library is unmanaged you'll have to use Pinvoke.
Generally speaking, a feature to call from managed code into unmanaged code (which I assume your DLL is) is called P/Invoke and generally involves annotating required static extern methods with attributes.
Add a reference to the dll in your project (selet browse to find it) and you should be able to access the functions within. As for how to make your device work with it, I think you're on your own :)
If the DLL is a .Net assembly, you can load it into a Visual Studio project by adding it as a reference.
In the absence of documentation, it can also be extremely helpful to load the assembly into .Net Reflector, which lets you inspect the guts of the assembly, even to the point of disassembling the code inside the methods.
1- If it is managed Dll , i.e. Written using .net framework than calling a method from the dll is like you are calling a method from your own class.
just add the reference of the dll in your project and include the namespace reference by 'Using' keyword.
2- If it is not than you need to import your dll dynamically, you can use [DllImport]
Related
Usually when we need to use native C++ DLL in C# program, write a manage wrapper is the way to achieve it.
Inside such program, If I press F12 (go to function definition) on a DLL function call, It goes to a C# file that looks like having all the functions forward declarations. I check the location of this file and it exist in the windows temp directory.
So my question is , When we uses a C++ unmanage DLL by manage wrapper in a C# program, Does .NET framework ( or any other component) create any temporary C# classes relevant to interface classes in the DLL?
There are no "temporary C# files". If you use Go to Definition and the IDE only has an assembly reference for the definition then it doesn't have a shot at finding the source code file for the definition. So it auto-generates one from the metadata in the reference assembly. That looks fairly similar to a source code file, but of course without any comments and without the code for the classes. It cannot be compiled. It is also in C#, even if the original assembly was created from C++/CLI or VB.NET code.
Nice feature, but don't confuse it for anything more than it is. If you want the IDE to take you to the actual source code file then you need a project reference, not an assembly reference, for the library.
I'm trying to use the lame_enc.dll file from LAME in a C# project, but adding the thing seems impossible.
I keep getting an error that says that a reference could not be added and to please check if the is accessible, a valid assembly or COM component.
I have no C++ experience, though I would like to use the functionality. Right now I'm using Process from the .NET framework to call lame.exe and do stuff, but I'd like to know if there's another way.
You can only add managed assemblies as a reference to a managed project. What I normally do in this situation is to add it as ressource instead with "copy local" settings. That way the DLL is tied to and deployed with your project. I then use DllImport to manually get the APIs I need from that DLL.
You have to use P/Invoke to call unmanaged APIs from managed code.
To use an unmanaged dll (native C++) in C#, you have to use DllImport, not adding a reference to the project in visual studio (and that is why you get an error).
Here is the documentation of DllImport from the MSDN.
You will need to use PInvoke to call functions in your native lame dll. However, you will only be able to call functions that have been exported as "C" style.
You can use a tool like "PInvoke Interop Assistant" that will help you when working out the PInvoke call signatures to make calls from C# to your native dll:
http://clrinterop.codeplex.com/releases/view/14120
In msvc i can write
#pragma comment(lib, "my.lib");
which includes my.lib in the linking stage. In my solution i have 2 projects. One is a class project the other is my main. How do i include the reference dll in code instead of adding the reference in the project?
Contrary to popular belief, it is possible :-)
To statically link .NET assemblies check out ILMerge. It's a utility that can be used to merge multiple .NET assemblies into a single one. Be it an executable or a DLL.
You could create a batch script that packages your assemblies together as a post-build step.
Edit: One thing to note however is that this does not remove the need to reference the library. The reference is still needed in order to compile your code that is dependent the external types. Much like including header files under C(++). By default c# assemblies are independent, there is no linking involved. However the tool I mentioned above allows you to create a new assembly with the external dependencies included.
As far as I know, you can't. If you need to access type that are included in a non referenced assembly, you'll have to use Assembly.Load().
I'm afraid you can't.
You can dynamically load the assembly via Assembly.Load(...) but then you have use reflection to explicitly create each Type you need to use.
I don't think you can include a dll from code without adding a reference. What you can do however is to use reflection to load that assembly and use a type from that assembly.
Assembly.Load() will get you a handle on the assembly and then you should be able to iterate through the types in the assembly.
Managed code doesn't use a linker. The C/C++ equivalent of a reference assembly is the #include directive, you need that in C/C++ to allow the compiler to generate code for an external type. Exact same thing in C#, you can't use an external type unless the compiler has a definition for it. The reference assembly supplies that.
The equivalent of C/C++ linking is done at runtime in a managed program. The JIT compiler loads assemblies as needed to generate machine code.
One thing you can do in a C# program that you can't do in a C/C++ program is using Reflection. It allows you to invoke a constructor and call a type's methods with type and method names as strings. Start that ball rolling with Assembly.GetType() and the methods of the Type class. However, consider a plug-in model with, say, the System.AddIn namespace first.
If you want to load an assembly at runtime, you can use Assembly.LoadFrom(filePath). But that way you are not referencing the assembly, and you can't use strong typing.
For example, you can have different plugins implementing a known interface (the one which is in a separate, referenced assembly), and have them all placed in a folder. Then you can check the folder and load all implementing classes at runtime (like in this example).
I'm trying to see if it is possible to pull data from a DLL. I did some research and found that you can store application resources within a DLL. What I couldn't find, was the information to tell me how to do that. There is a MS article that explains how to access resources within a satellite DLL, but I honestly don't know if that is what I'm looking for. http://msdn.microsoft.com/en-us/library/ms165653.aspx I did try some of the codes involved, but there are some "FileNotFoundExceptions" going on.
The rest of the DLL information is showing up: classes, objects, etc. I just added the DLL as a resource in my Visual Studio Project and added it with "using". I just don't know how to get at the meat of it, if it is possible.
If dlls are .net, you can use reflection.
Using System.Reflection;
....
Assembly A= Assembly.LoadFrom(YouDllFileName);
string[] STA;
STA= A.GetManifestResourceNames();
// STA contains all the resource names in the dll
...
// to extract them
Stream str= A.GetManifestResourceStream(STA[I]);
// then, you can make that stream became a file if you wish
You can also extract a .net assembly resources by using ildasm
I'm not totally sure what you might be running into based on your description, but a couple of general pointers...
If what you are trying to find is files you've added to the project you do this:
Right click on the resource in solution explorer, hit properties and set the "Build Action" to "Embedded Resource".
For strings and icons, add a .resx file to the project and insert them in there. If that's what you're doing and still running into issues, check the Build Action.
There is two types of dll.
Managed dll - dll that writen on any .net language (like csharp)
The link that you provide is working with managed dlls.
Unmanaged dll - classic c/cpp dll.
in this case you need to link between managed (your code) and unmanaged.
To find what the type of your dll, you need to add this dll as reference.
In visual studio open project, right click on references(in Solution Explorer).
Then "add reference"->browse-> add your dll.
Then at references, you can see your dll.
Right click on him, and add view in Object Browse.
If you see something like class "c" inside namespace "b", you working with managed dll.
In Object Browser you can learn a lot about your dll (maybe this is more important, than just extract resources)
At this point you can do the way that "Daniel Dolz" answer to you.
Since you say you are able to add the DLL in a using directive you can probably use the methods that the DLL exposes. If you do not have the documentation for the DLL then you may just have to try using the object browser to see what it has to offer.
assume:
using MyDll;
you should them be able to call the methods like this:
string x = MyDll.SomeType.GetValue();
is that what you were asking?
Env.: .NET / VS2008
Hi All,
My app uses a 3rd party DLL assembly separately installed on some systems (clearly identified) but not all of them.
Which means that on some systems, the DLL is not there hence must not be called. To solve this, I have 2 versions of the app (using 2 configurations) for the 2 use cases. In one of them, all calls to the DLL are #if'ed out.
Since there are no calls to the DLL compiled at all in the app(they're #if'ed out), is it safe to assume that the app won't try to load the DLL even though it is referenced?
Or should I also exclude the reference?
Note: Asked in reaction to womp's comment in this question.
TIA,
IIRC, the C# compiler will omit references to dll's that are never actually used in the code. So if all code is inside #ifs, the reference to the dll will not be there in your compiled app, and the dll will never be loaded.
You can check this using Reflector, by the way. Just drag & drop your compiled app into Reflector, and look at the References node. ILDASM also provides this feature, I think.
Caveat: DllImports and dynamic type loading (e.g., Type.GetType("type,dll")) will dynamically load dlls without the C# compiler knowing or caring. But again, if inside the proper #ifs, nothing will be loaded.
I would exclude it. It might load it no matter what and if you have a type reference, then that also could cause a problem.
Why not load the the assembly dynamically if needed/available? And then if its gets added at a later date you can just make use of it? You'll only need one version of your app also.
You are safe with a reference but without the actual DLL if you never (obviously) instantiate and referenced class AND never refer to the Class in any instantiated or referenced object.
Typically your DLL will be loaded the first time the Class Constructor of a referenced Class is run.
HTH
Jan