A .NET Interoperability Lesson: Mapping indexed properties to C/AL

Indexed properties are commonly used in C# because they allow a lot of syntactical flexibility, and make the code more readable, and easier to follow. Indexed properties are very similar to C/AL array indexing, except for two important differences:

  • In C/AL, indexer is always 1-based. In C#, indexers are 0-based.
  • In C/AL, indexer is always an integer. In C#, indexers can be any type.

These two examples show these differences:

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Trick: Instantiating any control in a Control Add-in

My two last blog posts tackled two aspects of working with control add-ins: making any property or method accessible to C/AL, and making any event accessible to C/AL The first was a simple trick, the second was a bit more complex. Together, these two tricks enable you to easily interact with whatever Windows Forms control the add-in shows: you can access any of inner control’s members – properties, methods, or events. At this stage, there is a very simple, but robust framework in place, which lets you publish any kind of control and make it fully available to C/AL. Cool.

But, couldn’t we make it a bit cooler? How about being able to instantiate any control, and having C/AL decide which control to instantiate, instead of hardcoding it in the C# code?

Yes, we can do this.

Trick: Subscribing to any Control Add-in event through pure C/AL

So, it worked. I found just enough spare time to try out the crazy idea I mentioned in the last post. It’s about control add-ins and events. In the last post I gave a tip about exposing the actual control as a property decorated with ApplicationVisible, which allowed you to directly access all properties and methods of the control.

However, if you wanted to do the same with the events, you had no other option but to manually create an event handler for each event type, then to add an event handler for the actual event from the original control, and finally to raise the event on your control add-in from the event handler for the actual control. You lost me already, so did I Smile

This is what I am talking about. Imagine a button, and that you want to allow NAV to respond to its Click event. This is what you need to do:

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Might not seem too much, but consider that you must do this for every single event that you want to use, that it requires some rewrite-restart-redeploy-redesign-rebind workout to implement support for another event you forgot last time, and then it becomes an problem. Probably the ugliest part of it all is the fact that for C/SIDE to properly insert the new event triggers for an updated class, you have to unbind the Control Add-in, and then to re-bind it. This loses any C/AL code in previously existing triggers. Add to the equation the human error variable, which kind of readily pops up whenever manual code duplication is involved, and you’ll have a lot of happy hours fixing the mess and juggling dlls and C/AL code back and forth.

How about this. How about not having to add anything at all to your C# source code, and not having to redeploy anything, and then to support any event you want just through a single line of C/AL code?

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Yes. That’s what this blog post is about.

By |August 4th, 2014|Control Add-ins|1 Comment|

Tip: Interacting with the actual .NET Control Add-in controls

The control add-in framework in NAV 2013 is great, because apart from allowing you to put a custom Windows Forms control on the page, it also allows you to interact with it through properties, methods, and events. In my classes I typically create a custom text box control that exposes a property to set the background color on the text box. It only takes adding a property of type Color, decorating it with the ApplicationVisible attribute, and you are ready to play.

However, if you want to enable setting all properties or invoking all of the methods the control supports, you could start wrapping the internal control into new ApplicationVisible properties and methods. There is no end to this.

Even though this is an incredibly simple concept, it just never crossed my mind: why not exposing the whole control as an ApplicationVisible property – this would in turn enable you to access the whole control, all its properties and methods (unfortunately, not the events – the delegates are still not supported in C/AL) without having to write a single additional line of code.

I give full credit here to my friend John who gave me thins hint. Thanks, John!

Here’s a practical example: you have a custom button control add-in that looks more or less like this:

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Why not appending this little piece of code (marked green):

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It costs nothing, but it allows you to do things like this:

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Or like this:

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Or, why not, like this:

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Even though the C/AL Symbol Menu will not give you access to any of the inner control directly, all the members are still there for you to access.

Again, as I said – you can’t subscribe to events. This is one of those limitations of .NET Interoperability I wrote about last year that I hope get sorted out at some point in future.

However Smile However… an idea has just crossed my mind and I’ll keep fingers crossed that I have enough time to try it out. If it works out, my next blog post will explain just that – subscribing to just about any event the inner control exposes.

Drag and Drop File Upload for Microsoft Dynamics NAV 2013 R2

Yesterday evening I spoke at Dutch Dynamics Community event, on invitation by my dear friend Luc van Vugt, and the topic was control add-ins for NAV 2013 R2. Of course, this automatically meant that the audience should see more JavaScript code than C# or C/AL, and that it should be something both fancy and useful.

So how about this: you drag and drop a file onto an NAV page, and the file is automatically uploaded and stored in a BLOB field in the NAV database? And yes, it does the same no matter if you call it from the Windows or the Web client. And yes of course, no external components or dependencies needed.

As I promised, I would make all the source components available for download after the sessions, and if you just want to take the components, here they are, ready to download, install and abuse:http://vjeko.com/wp-content/uploads/2014/03/DragDrop.zip

If you want to know how this thing works and why, read on. Otherwise, just download the thingy, install it (the instructions are included with the file) and abuse it to your fancy.