We have a .NET app that consumes COM-objects in different DLLs, also used in the VB6 part of our app. When referencing a COM library, Visual Studio 2012 creates an Interop.x.DLL and references that instead. Should I be distributing Interop.x.DLL from the build machine or regenerating it using some .NET command-line tool? What tool? What is the best practice for deploying a .NET app that references COM?
No, that is not necessary anymore since VS2010 and .NET 4.0. You simply set the Embed Interop Types property of the interop assembly reference to True. The default setting.
With this option in effect, the interop types get copied into your own assembly, as though you had written the [ComImport] declarations yourself by hand. And only the ones you actually use in your code. The feature pays off most for large ones, the Microsoft.Office.Interop assemblies in particular are very large. But of course always handy as well for small components since you don't have to deploy the interop assembly anymore.
Related
I have a .Net add-in and within this I have referenced a DLL I have made in C++/CLI. The DLL was designed against the OpenCV API - so now my .Net application can take advantage of the cool graphics capabilities offered by OpenCV.
The problem occurs when I deploy my add-in to other computers. When the user enacts a part of the program that specifically calls upon my C++ DLL it complains about missing the reference:
I suspect the code does not actually know where the DLLs are located but within my dev environment everything (obviously) works as I will have my environment set up different to your standard build PC.
What am I missing here ?
How can I successfully call DLLs created in C++ from a C# add-in? Bearing in mind add-ins are supposed to simplify the customisation of software like Office etc. This is very important - I have to be able to roll in non-.Net DLLs into my project and my code be able to find them.
My dll is just a plain dll, not a COM compatible dll (maybe it should be?) or should I be decorating my C++ code with __declspec(dllexport) a la https://learn.microsoft.com/en-us/cpp/build/exporting-from-a-dll-using-declspec-dllexport?view=vs-2017
So 2 things
Use Dependancy Walker to identify any dependancies on your dll and the dlls it uses further down the 'tree' hieracrchy. I found 2 that were missing and it wasn't obvious without this useful tool. Don't be overwhelmed with the results it gives you, just take notice of the missing dlls it's complaining about.
Make sure your dll is referenced within your project and not outside of it in some other folder where you built it.
This fixed my problem - in general just make sure your dlls are on the same path as your executable.
I am using a third party dll file which is referenced within a visual studio project using C#. In previous experiences on other projects, I was able to load objects from different dlls using dllImport, then create objects as if the source code of the dll was included in my project. However, that method is not working with the 3rd part dll. The program works flawlessly on the computer I am programming it on, however, when I run it on a different computer, it cannot find the dll. Is there a method to include the dll compiling and avoid using dynamic linking?
The default setting of .NET Framework is to load native libraries from system paths, not current directory.
But you might learn from System.Data.SQLite project (open source), so as to pre-loading native libraries from current folder, and based on OS bitness,
http://system.data.sqlite.org/index.html/doc/trunk/www/downloads.wiki
Although generating a mixed mode assembly (native and managed bits are merged) sounds like a better solution, System.Data.SQLite users often are confused. Thus, I recommend the pre-loading approach.
I have a .Net Com Dll is it possible to use this dll and create .OCX file in c++ or MFC. If yes what are all the steps which needs to be followed. If any sample code is availabe that would be a great help
You could expose the .NET assembly as COM object using the regasm.exe tool. You could use the [ComVisible(true)] to indicate that all classes should be visible by COM clients when registered. This assembly level attribute could also be set in the properties of the project in Visual Studio. You could also apply it only to some classes that need to be exported. Once the assembly registered as COM object you could instantiate any class from unmanaged clients as with any standard COM object.
There is nothing particularly special about an .ocx file, it is just a DLL. Microsoft came up with that filename extension back in the Visual Basic version 4 days to make it obvious to VB programmers that they had a DLL that contains controls. ActiveX controls as opposed to VBX controls from the 16-bit days.
If you made the .NET assembly [ComVisible] then you already have a COM server that's usable in other projects. Provided you registered it properly, .NET assemblies must be registered with Regasm.exe instead of Regsvr32.exe. Done automatically in a .NET project with the Project + Properties, Build tab, "Register for COM interop" option. And at installation time with a Setup and Deployment project. If you need a type library then use Regasm.exe with the /tlb and /codebase options. Or Tlbexp.exe
If this really needs to be a traditional .ocx, in other words have controls, then you can use a Winforms UserControl or your own class derived from a Winforms control. Winforms automatically implements the plumbing to make classes derived from the Control class function properly in an ActiveX host.
If you're wanting to use a .NET library in normal C++, there are ways, mostly involving COM Interop. Microsoft has a whole section of MDSN dedicated to COM Interop: http://msdn.microsoft.com/en-us/library/6bw51z5z%28v=VS.71%29.aspx.
If the .NET DLL supports COM Interop, use that.
Try using VC++'s #import directive to read the .NET DLL in as a COM object. When compiled, VC++ should output a .tlh file and a .thi file (header and implementation respectively) which will be automatically compiled into your project. But this may or may not work depending on the DLL's construction, dependencies, etc.
Look at creating your own COM Interop .NET wrapper library that marshals calls to the base .NET DLL.
I have perhaps a silly question:
We have a VC++ COM DLL (developed internally) and we have ported our main app to C# and used COM Interop, reg-free to access the COM dll. Everything works just fine with internal embedded manifest.
However, the friendly product-dev/marketing/sales want to minimize the package and include the COM dll directly. Somehow, someone became convinced that the app distro should include the exe only (since it's unmanaged we can't just ILMerge it in).
Since we have the tlb/lib of the COM, could we somehow statically link it, without porting the whole COM to C# managed re-work?
Thank you
P.S. Pardon my wording: the company was downsized and I am the Python guy who had to learn everything .NET in the last week or so since now I am doing my job and the job of 2 ex-senior .net developers
It looks like Costura can more or less do this.
https://github.com/Fody/Costura
It specifically has support for merging unmanaged assemblies (ie a C++ DLL) into a .NET assembly.
Note - this is not true static linking but would achieve the aim of packaging everything in the single EXE to be distributed.
It is possible to include the source for the COM DLL into the project for the exe, or you could change the COM DLL project into a static lib project. Once you've accomplished that, you must modify the code to create the COM objects directly. All said, neither options are particularly easy.
Alternatively you could look into products like Spoon Studio that would allow you to wrap your exe and COM DLL into one exe without any code.
I am creating a Class LLibrary in c# by using microsoft provided Dll's.
Now i want to statically add those Microsoft provided libraries to My Dll.How can i do this.
I have simply added a reference to those Microsoft provided Dlls and creating My Dll? Is it fine or not?
if Microsoft provided dll is not available on other machine then my Dll may fails i need to add the libraries statically??
How can i do this??
There's no such thing as statically linking to another assembly in .NET. There are some third party products such as .NET linker that merge assemblies into one but they are unsupported.
If you have the redistribution license for that library, you can ship a copy along with your assembly. In Visual Studio you can make this happen by setting "Copy Local" to "True" in the properties window for that assembly reference.
See discussion here and read the comments -- Jeff does provide a way.
http://blogs.msdn.com/b/microsoft_press/archive/2010/02/03/jeffrey-richter-excerpt-2-from-clr-via-c-third-edition.aspx
If the dll is not available at execution time; yes it will fail. However:
many Microsoft dlls are pre-installed with .NET (caveat: "client profile")
many of the Microsoft dlls are redistributable; so you can include them with your package
There isn't a linker provided in the core framework, although ILMerge may be useful.
Its not very clear what you want to achieve but it seems you are concerned that your class lib will work on some other machine or not. The thing is that the .Net framework is a free redistributable which should be installed if not present on the target machine. With the .Net framework already installed on a machine, there should be no problem as such.
Static linking as such does not make sense in .Net other that adding an assembly reference to your project. Hope it helps