Is it possible to use a VB6 class in C#?
I think you should just be able to add the library that contains your VB6 type as a reference in your C# project. Visual Studio will create an Interop Assembly on the fly, and you'll get access to all of the types in the VB6 library via Runtime Callable Wrappers.
The tool that creates the Interop Assembly is TLBIMP.EXE, and you can run this yourself if you want more control over the process, eg. if you want to create a Primary Interop Assembly that might be shared by multiple managed components.
You can use a compiled VB6 dll in a C# program by using COM Interop.
https://stackoverflow.com/questions/tagged/interop
As #Wayne states in his post (+1) it is absolutely possible.
I would go for a rewrite of your VB6 class:
If you have the VB6 source and the funding, I would recommend you to rewrite the class in C#.
Although VB6 may live forever :
Current support Statement for Visual Basic 6.0
Sure, you just need to make it a COM object.
Related
I got an desktop application which uses a small DLL written in C# registered as an COM object to collect some infos from Active Directory. The app is written in C++, it works fine. I would like to write a small app in C# which would call the same registered DLL's methods (kind of testing tool), but can't figure out how to do this without referencing the COM DLL at compile time (I really need to use the COM registered dll)
I followed this article, managed to instantiate the object, but i cannot cast the instance to my interface created from IDL. Also the debugger knows the exact type of the instance with all members shown. I suspect this is due the DLL is loaded in the CLR as well.
Is this even possible?
thanks
You can't. The IDE will refuse to let you add a reference to the type library. You can fool it by using late binding. But that still doesn't fool the CLR, it won't create both a CCW and an RCW. You'll need a native client, like C++ or a scripting language to truly exercise the COM specific path.
There's just no point, just use the assembly reference directly and use normal C# code to test it.
You can consume a COM component from a C# project. The general steps are as follows:
Locate a COM component to use and register it. Use regsvr32.exe to register or un–register a COM DLL.
Add to the project a reference to the COM component or type library.
When you add the reference, Visual Studio uses the Tlbimp.exe (Type Library Importer), which takes a type library as input, to output a .NET Framework interop assembly. The assembly, also named a runtime callable wrapper (RCW), contains managed classes and interfaces that wrap the COM classes and interfaces that are in the type library. Visual Studio adds to the project a reference to the generated assembly.
Create an instance of a class that is defined in the RCW. This, in turn, creates an instance of the COM object.
Use the object just as you use other managed objects. When the object is reclaimed by garbage collection, the instance of the COM object is also released from memory.
For more information, see Exposing COM Components to the .NET Framework.
Detailed Article
I would suggest you use the .NET 4.0 dynamic type instead of all the mess of dealing with reflection in that article you mentioned
I am trying to read GUID attribute of a C#.net assembly from c++ (VC++ 10).
I should mention that, I don't want to use .net or .net reflection. looking for a pure c++ way.
what is the solution ?
Thanks in advance.
You need to use the Unamanaged Metadata API
and especially the IMetaDataImport::EnumCustomAttributes Method
That's going to be quite a work... Here is a link that gives a good starting point on this (it's C#, but the ideas are exactly the same, and is in fact easier to program in C++): Reading types from assembly
Check out the The .NET File Format MetaSection over at CodeProject.
i understand you don't want to use reflection or .net.
You do however want to get the GUID from a C# dll you have, that was built with .NET.
The common way C# developers make their class libraries available to COM-based developers is to use the tlbexp.exe (type library export) tool to export a type library file.
The COM-developer can then use the .tlb file in their COM code.
When the C# developer builds the dll they either put the Guid manually in the AssemblyInfo level (in .NET) or the compiler will generate the Guid automatically when building the dll.
show how the COM client (C++) is built to use the COM server (C#)
http://msdn.microsoft.com/en-us/library/aa645738%28v=vs.71%29.aspx
note that in this article refers to another tool regasm.exe which registers the dll and can export the tlb at the same time but it is not necessary to register the dll on your system
as a developer you can just use the tlb file
How would I export functions defined in a C# class library, while enabling them to be imported to and called from an unmanaged C++ application/DLL ?
Strictly speaking, you can't just export functions as you would in a classic .dll, as .NET .dll's aren't really .dll's at all. Your only three options are:
Use managed C++
Expose your C# classes as COM objects and consume them from your C++ code
Host the .NET runtime in your C++ project and interact with your C# classes through that.
Your C++ Apllication would have to start by hosting the CLR. There is nothing special required from the .NET DLL.
You would not. Not supported. You can pretty much only export COM objects from a C# class librarly.
You could also make a C++ wrapper for your C# library - a simple Managed C++ DLL that would import .NET methods and export them natively. This adds an additional layer, but it might be useful if C# library is a must have.
Another option is to tweak the compiled assembly to export the functions. A C# compiler cannot do this, but it takes a slight change of MSIL code to get the things done.
Have a look at this article - there're some links on how the stuff works, and a tool to automate it (though I haven't tried it myself).
Pretty much what it says on the tin. I've tried googling around but can't find anything helpful.
I'm trying to automate a process and part of that involves running forms/VBA code from an access 2003 database. What's the best way to call these from C#?
The Primary Interop Assemblies let you to automate Access 2003 from your C# application. In particular, you should be able to use commands like DoCmd.OpenForm and DoCmd.RunCode, allowing you to run your Access 2003 forms and VBA code.
Create the VBA code in a separate COM dll, and then you can use COM interop to call from C#
For instance, see SO question: Using a COM dll from C# without a type library.
Exposing COM Components to C#
You can consume a COM component from a
C# project. The general steps are as
follows:
Locate a COM component to use and register it. Use regsvr32.exe to
register or un–register a COM DLL.
Add to the project a reference to the COM component or type library.
When you add the reference, Visual
Studio uses the Type Library Importer
(Tlbimp.exe), which takes a type
library as input, to output a .NET
Framework interop assembly. The
assembly, also named a runtime
callable wrapper (RCW), contains
managed classes and interfaces that
wrap the COM classes and interfaces
that are in the type library. Visual
Studio adds to the project a reference
to the generated assembly.
Create an instance of a class that is defined in the RCW. This, in turn,
creates an instance of the COM object.
Use the object just as you use other managed objects. When the object
is reclaimed by garbage collection,
the instance of the COM object is also
released from memory.
I want to add a VC++ DLL reference into my C# Visual Studio project. But when I try to add it I see, "It is not a valid assembly or COM component".
Please suggest how I can use the VC++ DLL as a reference in a C# project.
There are two options for using a C++ DLL from C#: either COM interop, or P/Invoke. COM Interop involves creating a COM object in your C++ DLL, and then adding it as a reference. You can use the COM object like a C# object (for the most part) at this point.
P/Invoke allows you to call exported functions from C# (think calling standard Win32 API functions from C#). This is likely easier to set up, since all you need to do is export a function, however that could cause you to refactor your code in the C++ DLL, since it's not a very OOP way of doing things.
You can only use C++ components in C# when they have been prepared for use, for example by being written in C++/CLI or being written as a COM server.
If your component is a plain C++ dll you'll need to write some wrapper code, probably best is C++/Cli
I am not sure whether this solve..
run:
tlbimp /out:MyOldCom.dll MyNewAssembly.tlb
Then use it as you would any other assembly.
Please refer
http://msdn.microsoft.com/en-us/library/aa302324.aspx
http://msdn.microsoft.com/en-us/magazine/cc301501.aspx
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One way is to package your DLL as a COM class and Another way is using DllImport