Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people, just like you, are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
Solved

WPF project and COM objects

Posted on 2015-01-12
6
240 Views
Last Modified: 2015-01-12
Hi Experts,

I have a WPF application that talks to a CLR class library that calls into C++.  The reverse is proving more difficult.  I've seen the method where you can pass a delegate as function pointer, but I find that too intrusive and need to change my C++ implementation to support it.

So I think my current best option might be to turn a class in my WPF application into a COM server.  I have done so, but since this is a WPF application, there is no dll output.  Clearly I could create another intermediate class library just for this COM object, and then use this class library from my WPF application.  But is there a way to use the exe instead of a dll to register in WIndows?

Also, if I do use an intermediate class library, how do I get this COM object to talk to the rest of the WPF application?  I can't instantiate it in my WPF program and have it CoCreated by the C++ native code that will be creating it as well....  

Thanks,
Mike
0
Comment
Question by:thready
  • 3
  • 3
6 Comments
 
LVL 86

Accepted Solution

by:
jkr earned 500 total points
ID: 40545871
>> The reverse is proving more difficult.

Have you considered just passing windows messages to the WPF app by the C++ layer? Not sure if that is applicable, but you can pass a lot of stuff via the message parameters.
0
 
LVL 1

Author Comment

by:thready
ID: 40545880
I did not think of that.  That's a much simpler idea!  I can keep this out of the cross platform c++ and inside of the class library as well...

I'm still curious about how one is supposed to CoCreate a class and have the class implementation talk to WPF...   It's created by the C++ side, so then it's in-process.  Does this mean that callbacks from the COM class will need to be static?  (I wonder if I'm not making sense here)....
0
 
LVL 86

Assisted Solution

by:jkr
jkr earned 500 total points
ID: 40545886
You could still pass a C# delgate sink to the class in question upon construction or via an 'InitializeContext()' method after creating it - yet it is still a bit  to vague to say 'just do it'.
0
Free Tool: IP Lookup

Get more info about an IP address or domain name, such as organization, abuse contacts and geolocation.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

 
LVL 1

Author Comment

by:thready
ID: 40545900
I don't really understand that method.  It makes sense to me, but how to do it with a .lib...  I don't know...  I'm starting to lose interest in trying to keep all business logic in c++ so that it's reusable everywhere.  Too time consuming- and what does it give me?  Not that much in the end.  I just wish my code base would never have to be touched again... But it seems I keep writing the same kinds of things for new projects.

If I do everything in C#, I'll be much better off.  Just no cross-platform stuff.  Please talk me out of dropping this if you think it's all worth it?  :-)
0
 
LVL 86

Assisted Solution

by:jkr
jkr earned 500 total points
ID: 40545903
If you can do most of the stuff in C#, even the better - yet since you are still vague about your setup, it is hard to give any advice. If e,g, your underlying C++ lib&dll can take a target window handle that receives the messages I mentoined earlier, you could pass structs/classes via the 'lParam' parameter (either by custom messages or by utilizing WM_COPYDATA) that are close to give you the flexibility you might need.
0
 
LVL 1

Author Closing Comment

by:thready
ID: 40545909
I have/had a goal to write all my business logic in pure cross-platform c++, with the idea that c++ was the most common denominator between systems with the best chance for reuse.  However, I don't have much code, but wanted to write everything one last time.  I think I'm not getting that much out of this goal though.  And I do like C# best.  I think in the name of completing projects fast with less headaches, I'll stick to C# for now....   and hopefully not kick myself later on..
0

Featured Post

Free Tool: Postgres Monitoring System

A PHP and Perl based system to collect and display usage statistics from PostgreSQL databases.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Exception Handling is in the core of any application that is able to dignify its name. In this article, I'll guide you through the process of writing a DRY (Don't Repeat Yourself) Exception Handling mechanism, using Aspect Oriented Programming.
It was really hard time for me to get the understanding of Delegates in C#. I went through many websites and articles but I found them very clumsy. After going through those sites, I noted down the points in a easy way so here I am sharing that unde…
The goal of the video will be to teach the user the concept of local variables and scope. An example of a locally defined variable will be given as well as an explanation of what scope is in C++. The local variable and concept of scope will be relat…
The viewer will learn how to use the return statement in functions in C++. The video will also teach the user how to pass data to a function and have the function return data back for further processing.

856 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question