Development – Page 5

Excel Interoperability Woes in NAV 2013

Post published:December 24, 2013
Post comments:30 Comments
Reading time:4 mins read

Handling Excel files in NAV 2013 (including R2) is not as easy as it seems at first. The Excel Buffer table – an obvious choice of the old days – supports only Open XML format (*.xlsx), and Excel Interoperability implementation seems a bit buggy (check the comments in my old post about .NET interoperability: https://vjeko.com/blog/the-beauty-and-the-beast-nav-and-net). You can still use automation, but then you must handle everything, or at least most of it, on the client end. And, to make it all just a bit worse, none of these approaches, even when they work, will impress you with their speed. All in all, if you want to handle legacy Excel files (*.xls) you will have to make some compromises.

Last week, Mark asked me for a bit of help on a project where he had to import *.xls files into NAV 2013, and he hit all of the possible walls provided by the Excel Buffer, .NET Interoperability components for Excel, and automation walls possible.

When I gave Mark my solution, he said: you should blog about this. So, here I am, blogging about a simple way to read data from Excel, any version, lightning fast.

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Top 10 things I miss in .NET Interoperability in NAV 2013

Post published:June 19, 2013
Post comments:25 Comments
Reading time:21 mins read

If you ask me what the top addition to the NAV technology stack over the past few years is – it’s .NET interoperability. A lot of folks, maybe you as well, would disagree, and say it’s Web services. They are important. But if you are a NAV developer, Web services don’t make your life any easier. You are programming for Web services when your requirements tell you so, but that’s it. You don’t experience those moments of truth, when it dawns on you, when you go eureka, slap your forehead and say: now this is something I solve with Web services! Not quite.

But with .NET interoperability, it’s a different story. If you know how to harness its power, there is no single project you’ll ever want to go without using .NET. It opens the door to the most powerful development framework for Windows, and it makes many impossible things possible, in pure C/AL.

There are two kinds of things in this world. Those that .NET Interoperability can do, and those it can’t. Microsoft has been steadily improving it since the initial release in 2009 R2. However, there is still much to be desired. Those small things that you cut in C# in seconds, and twist your brain inside out for hours before you realize you can’t do it in C/AL. Some of them may be in a backlog somewhere in Vedbæk, but I don’t know that, so I decided to compile a list of top 10 things I believe C/SIDE should support, and it doesn’t.

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Transaction Integrity with Connected Systems

Post published:March 5, 2013
Post comments:3 Comments
Reading time:6 mins read

Broken pencil With .NET Interoperability around, it’s very likely you’ll be synchronously calling external web services from C/AL, to exchange data. I won’t go into discussing whether or not this kind of architecture is good (my own position is that it isn’t), you may end up having situations where your C/AL code simply makes a synchronous call to external systems, such as web services.

Any external call is an expected point of failure. An important question you must always have in mind when calling external functions is transaction integrity. When writing code that targets only NAV, the structure of code is largely irrelevant, as long as you are not using COMMITs (which is another thing you should avoid at all costs). However, as soon as you introduce external calls, the structure becomes critically relevant. Critically relevant.

I’ve talked about this during my 2012 NAV TechDays session, and I promised I’d blog about it – so, here it goes.

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Cross-Call State Sharing in Web Services

Post published:February 21, 2013
Post comments:11 Comments
Reading time:12 mins read

Web services in NAV have an interesting feature: they are stateless. For a system which is pretty stateful otherwise, this feature can be outright annoying. You must get used to it, and then make sure you never ever write code as if there was any state preserved on the other end.

The reason for this is simple – there is no actual protocol that you use to communicate with NAV through SOAP. Calls are ad-hoc, essentially atomic, each one can accomplish a great deal of things in a single go, and it makes programming a whole lot simpler. The price you pay is the state. Once you close the connection, the session ends and the transaction commits (or rolls back). Next call starts from scratch.

If you need to preserve any state between the calls, whatever that state might be, you are toast. NAV simply doesn’t support it out of the box. A common misconception is that single-instance codeunits help. They don’t. The single instance is always single per session, and since each call is an isolated session, it means that each single instance codeunit dies at the end of the call.

Pretty annoying, isn’t it?

Well, it is, and it isn’t. I won’t argue about validity of situations where you need to preserve state across multiple web services calls – I am going to show you how to do it when you need it.

And what I’m going to show you works in both NAV 2009 R2 and 2013.

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Some tips and hints about temporary tables

Post published:November 1, 2012
Post comments:9 Comments
Reading time:10 mins read

Temporary tables in NAV are a great thing, and are frequently used, but there are some misconceptions about them. I see developers do the same mistakes time after time and again. In this post I’ll address some common misconceptions and give some tips and hints that you can use in practice.

There may be a lot of basics for you here, in which case just skip to the end: there I give you a nice tip about how to prevent accidental changes to physical tables when you expect that a table is temporary, and in fact it is not.

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