Expose your app's objects / A true plugin model.
This sample will teach you how to expose classes from an ActiveX EXE to other Applications. I felt that a Main App / Plugin relationship (like in Photoshop) will be best suited to showcase this cool solution.
This is how it works:
When an object gets created based on a class from an ActiveX Exe it gets created
in its own memory area (Multiple objects based on the same class cannot share
their data). In C++ that object registers itself with the ROT (Running Object
Table) so that anybody who needs to, can access that instance of the object.
For instance Excel. When Excel is running you can refer to the running instance
from VBA/VB, and access any data that's present in the spread sheet. However
VB based objects lack that functionality. Activex EXE created in VB will NOT
get registered in the ROT! (That's why you can't use GetObject on VB made ActiveX's
;-) )
Anyhow, here is a solution that will register your ActiveX EXE in the ROT,
and you will be able to reference the running instance of your object from any
other application.
Please use this sample as follows:
Extract Files from Zip (use folder names checked)
run MainApp.EXE (ActiveX EXE)
click on the OPEN icon
load the supplied BMP
wait for a few sec....(sorry the image handling is awfully slow, I didn't
wanted to deal with DIB's for simplicity reasons)
plugin Button should be enabled by now (this calls a ShellExecute and runs
a regular EXE (our plugin)
In the plugin click on GetData (this will transfer the image from the main
app)
click on modify image (thanx Rog3r)
click on Close Plugin & Transfer data (this will transfer the modified
image back to the main app)
Voila
The benefits: If you expose your app's objects up front, you can later on create
any plugins/addons you want without modifying the original app.
This is my first contribution to planet-source-code. Please let me know what
you think (bad/good, anything is welcome) and like always VOTE.
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Terms of Agreement:
By using this code, you agree to the following terms...
You may use
this code in your own programs (and may compile it into a program and distribute it in compiled format for languages that allow it) freely and with no charge.
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Autoredraw, setting on the MainApps picturebox, should be set to true. Or you could redraw the picturebox whenever the form refreshes... (If this comment was disrespectful, please report it.)
I was excited to see this code! It can solve a long time problem for me. I had trouble using it in my Webbrowser project, though, because VB6 keeps telling me the class object cannot be public 'in this type of project'. I've tried to research it, but can't solve the problem. I would appreciate any suggestions. thanks, Joe (If this comment was disrespectful, please report it.)
I was very happy to see your code but when I tried to use it in my WebBrowser project, VB6 keept telling me the class object cannot be public 'in this type of project'. I've tried to research it but need any suggestions you might have to help. Thanks for your code, Joe (If this comment was disrespectful, please report it.)
Very nice. If I load more than one picture, the plugin seems to still use the first one. Why is that? (If this comment was disrespectful, please report it.)
Johny: I am not sure why, I have not been working with the code for a while now. I will check it tonight though.... (If this comment was disrespectful, please report it.)
Love it! Might use it in a professional edition of one of my gfx progs!! -THNX SO MUCH. 5 from me. (If this comment was disrespectful, please report it.)
Nice plugin. I bet that greyscale would make a very intresting terrian with some modification. (If this comment was disrespectful, please report it.)
8/13/2003 8:15:20 AM:
Works great on my machine, however how do I get the client to work if it is sitting on a different machine. (If this comment was disrespectful, please report it.)
Very Nice. I didnt thought Plugin was even possible in VB. But You did really great work. Thanks for sharing it with All of Us. Regards Er. Gurpreet Singh
(If this comment was disrespectful, please report it.)
Great code i did not think you could make plugins a exe. Ive tryed to use dll's and i always get the cannot create object but this code may work perfect for it thanks for sharing this code. 5 Globes! (If this comment was disrespectful, please report it.)
thank you, i was looking for a solution to some of my problems.... (If this comment was disrespectful, please report it.)
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10/27/2000 10:02:06 AM: 
