.NET (Core and Framework)

5-Sep-02 0:31

Hi,

How do I go about creating a plugin architecture for my .NET application? The plugins should be able to access the object model (receiving events and performing validation) and to extend the UI.

First of all, do I have to create a new AppDomain? If yes, one for each plugin or one for all?
Second, if I've loaded a plugin Assembly, what do I do then??? How do I connect it to my application?

Or am I on the wrong track and need a completely different approach?
Are there any samples, walk-throughs, guidelines etc.?

Thanks in advance for any help you might provide.

Regards,
Andreas

Stephane Rodriguez.5-Sep-02 1:08

5-Sep-02 1:08

Plugins are now old fashioned when you regard that System.Reflection allows you to create classes, compile them, and add them to your code while it's running.

You may of course end up loading custom user Assemblies after your program has been released, but that's not there the true power lies : custom user Assemblies must export functions whose signatures are already known by you BEFORE you have released the program.

Good luck!

And I swallow a small raisin.

Anonymous5-Sep-02 3:20

5-Sep-02 3:20

And this means practically...?

I did have a brief look at the .NET documentation on dynamic assemblies, but I figured out that, this way or the other, I ended up getting a System.Reflection.Assembly, right?

The idea is, that users should be able to extend the basic functionality of the app. Is this an old-fashioned concept? I see this as a critical point for the success of my (freeware) program in order to compete with products already on the market.
There are certain regional validation criteria that need to be taken into account, but I cannot code them into the main program because I simply don't know all of them and never will. So therefore I am looking for a way of letting the program be extended through some kind of addin modules. I don't insist on using precompiled assemblies, they could be compiled JIT.

But my problem remains: How do I make them interact with my app?

An addin would have to consist of one or more classes derived from a predefined abstract addin class, wouldn't it? Then, the constructor could receive as a parameter a reference to one of the necessary objects.
But how do I get to such a class if I don't know the name of the class? That I would need for Assembly.CreateInstance().
And if I somehow managed to create an instance of such a class, wouldn't I run into problems with the GC sooner or later, like with .NET Remoting?
And do I need one or more private AppDomains or would I load it into the AppDomain of my app. Are there any requirements and advantages/disadvantages?

Regards,
Andreas

Stephane Rodriguez.5-Sep-02 3:31

5-Sep-02 3:31

Answering your question in full extent requires more than a textarea.

May be it's me, but you seem to explain things as a true callback C-style programmer.

Java and C# have a different paradigm.

In this paradigm, a plugin for instance subscribes for predefined events you expose in the program. Doing this, nor your program, nor the plugin are not stuck with predefined method signatures, useless marshalling and stuff.

As for freeware and competition, I just would like to tell you that you should balance the usefulness of a .Net application instead of a standard C/C++/MFC/VB or even Java app. In other words, users of your freeware will have to download 21MB of run-time (+6MB for SP2), just to run your .exe. As long as they don't, they'll get a nasty "missing mscoree.dll", and chances are they spit on you and throw the freeware to hell. Big Grin | :-D

And I swallow a small raisin.

Anonymous5-Sep-02 4:15

5-Sep-02 4:15

Sorry, but I am not a C programmer. I'm not that old! Wink | ;-)

I do know Java, C++/MFC, C#/.NET, say OOP in general. And I was definitely not thinking of callbacks, that is not even possible in this case. My problem is that, until now, I have only written (non-extensible) standalone programs and am not familiar with any kind of plugin/addin/othernameforextension architecture programming, neither C-style nor C#-/Java-style.

I have an *object model* (object-oriented) with what I would see as "predefined events". And I didn't intend to call plugin functions *from* that OM in any callback style, I did want the *plugin* to register for the events it needs. The question is: How?

I do not feel bound to any specific programming paradigm, I was just asking for *any* way to have an extensibility mechanism ... I am open for any OOP approach to this problem!

Regards,
Andreas

P.S. I do "need" the .NET Framework for this programming task, regardless of its download size.

Stephane Rodriguez.5-Sep-02 4:37

5-Sep-02 4:37

Anonymous wrote:
The question is: How?

Short answers :
- declared events are made public in the assembly, so that the plugin assembly can register one or more of these events by adding a reference to the main assembly, and creating new event instances.
- assemblies can be dynamically emitted or loaded with a .config file, a separate file from the main assembly.
- that said, assemblies may communicate explicitely, not explicitely, synchronously, asynchrounously, use a message queue, etc. that's up to you and your requirements. In fact, that's your specific use of the .Net framework.

Long answer : answering the question is as broad as answering the question : "I want two programs to communicate, how ?"

Now good luck! I am not an interested party here, but from what I see on the MSDN samples for instance, you have plenty of code to begin with. Cool | :cool:

And I swallow a small raisin.

Anonymous5-Sep-02 9:56

How can I develop a Keyboard driver

5-Sep-02 9:56

Thank you very much for that hint! Such an easy solution using the appSettings... Smile | :)

I know how to register for events, but that did require access to an *instance* of my class first, not just setting a reference.

I have now managed to get a simple sample running, merci beaucoup.

Andreas

Katiucia4-Sep-02 7:45

Katiucia

4-Sep-02 7:45

Hi,

I am a Brazilian developer and I need to create a brazilian
keyboard.
I know that I need to change the VKCHAR table and sckxtmsengus1.cpp,
what methods needs to be change?
Could anybody give me more information?

Thank you in advance.

Katiúcia Freitas da Silva
Phone: + 55 35 3471 9300
e-mail: katy_freitas@hotmail.com
ICQ#: 127458845

Dinamic Web Reference

bad4-Sep-02 1:37

bad

4-Sep-02 1:37

Is there any way to load the we breference "on the run" ?

BAD

Re: Dinamic Web Reference

buke5-Sep-02 3:08

buke

5-Sep-02 3:08

Sure there is, for someone from the MS tech surport center told me. But I can do it by myself, and I have not found a single sample in C++ ATL. Pity.

Any one knows?

Web Deployent projects

bad4-Sep-02 1:32

bad

4-Sep-02 1:32

Genius indeed. I even read an article on Code Project about this.
Now, here's a problem. Suppose I have a few web sites on the same IIS server. Here goes the question: how do I do, so that the kit created as a web deployment project to install the application on another web site but the "default web site" ?
I tryed stopping all the other web sites but the one I want to install onto, but it doesn't always work.
Does anybody have a better idea ?

BAD

Question about ATL Web service

buke3-Sep-02 22:27

buke

3-Sep-02 22:27

As a beginer of ATL Based Web Service programmer, I have some some questions about it:
1)Whether a Web Sevice can hold its state during its serving many clients, for I want keep some data structs among clients because these clients are collorating doing a certain work. If Web Service can has this virtue, how can I do, are there some documents about it?

2) can a web service client dynamicly locate the server without recompiling its source files When a Web Service provider changes its location on the internet? If it can, how can I do and are there some documents about it?

Please help me, thank you!

oyyx@sina.com

References Queries

Firoz2-Sep-02 22:52

Firoz

2-Sep-02 22:52

Hi,

I have two Queries...

First:

Is there any way by which I can Specify (In my Assembly itself) that
the CopyLocal Property of a Reference to my Assembly should be False?

ie: Whenever my assembly is added into any Project (References), the
CopyLocal property for that Reference should be False by default.

Note: It should be possible without making the Assembly Strong Named.

And,

Does the Framework/VisualStudio IDE raise any Event or send any kind of
Notification to the Assembly when a Reference to it is Added or Removed 
from a Project.

ie: I want to execute some code from within my assembly when that Assembly is
Added or Removed from the References collection of any Project.

Thanks,

Firoz

.Net and Tool-window

Tomas Petricek2-Sep-02 8:22

Tomas Petricek

2-Sep-02 8:22

Hi,

I want to have tool windows in my application but I don't know how can I create window, that is above application main window Confused | :confused:

When TopMost==true this window is above ALL windows and
when TopMost==false this window can be under main application window Frown | :(

Thank you (And I'm sorry about my english)

Tomas Petricek

Re: .Net and Tool-window

James T. Johnson2-Sep-02 11:27

James T. Johnson

2-Sep-02 11:27

Use the AddOwnedForm method on the main window; passing in the instance of the tool window.

James
"And we are all men; apart from the females." - Colin Davies

Re: .Net and Tool-window

Tomas Petricek2-Sep-02 13:25

Tomas Petricek

2-Sep-02 13:25

Thank you

RichTextBox

Iulian Serban1-Sep-02 8:00

Iulian Serban

1-Sep-02 8:00

Hi
This is my first post to CodeProject Smile | :)

.
I have tried to insert an image into a RichTextBox component but with no result. I have tried with CreateGraphics and drawn an image into it but when I type over the image, it dissapears.

If I load a rtf file containing an image it works just fine but how can I include an image programmaticaly?

I included a Com object RichTextBox6.0 and it has an array of ole objects with the add method but I don`t know what to give it as parameters.

Can anyone help me?

SOAPCLIENT_SEND_ERROR and ERROR_IO_PENDING

Eugene Plokhov31-Aug-02 19:57

Eugene Plokhov

31-Aug-02 19:57

I'm trying to access XML Web Service using C++ and I've got two

problems.

First, when I try to invoke web service's method from another thread

(not UI thread) I get SOAPCLIENT_INITIALIZE_ERROR error.

Second, when I pass to web service BLOB data which length is greater

than approximately 800KB I get
ERROR_IO_PENDING error (returned by GetLastError).

Is there any way to invoke web service's methods in worker threads and

to pass in BLOBs that are larger
than 800KB (C# client can send about 3MB)?

WinForms form hiding

Boris Yankov30-Aug-02 5:19

Boris Yankov

30-Aug-02 5:19

I want to hide my main form when it is shown so it remain only in the tray.
If I try to hide it in the OnLoad event it is reshown. The same with Visible = false;
How can I do that?

Re: WinForms form hiding

Stephane Rodriguez.30-Aug-02 6:12