Rash thoughts about .NET, C#, F# and Dynamics NAV.

If you are a Dynamics NAV developer you have probably heared of the web services feature which comes with the 2009 version. In this walkthrough you can learn how to create and consume a Codeunit Web Service. This method works very well if you only need to create the C# proxy classes once. If you have more than one developer, an automated build system, changing web services or many web services then you will come to a point where this code generation system is very difficult to handle.

Microsoft Visual F# 3.0 comes with feature called “type providers” that helps to simplify your life in such a situation. For the case of WCF the Wsdl type provider allows us to automate the proxy generation. Let’s see how this works.

Web service generation

In the first step we create the Dynamics NAV 2009 Codeunit web service in exactly the same way as in the MSDN walkthrough.

Connecting to the web service

Now we create a new F# console project (.NET 4.0 or 4.5) in Visual Studio 2012 and add references to FSharp.Data.TypeProviders, System.Runtime.Serialization and System.ServiceModel. After this we are ready to use the Wsdl type provider:

At this point the type provider creates the proxy classes in the background – no “add web reference” dialog is needed. The only thing we need to do is configuring the access security and consume the webservice:

Access from C#

This is so much easier than the C# version from the walkthrough. But if you want you can still access the provided types from C#. Just add a new C# project to the solution and reference the F# project. In the F# project rename Program.fs to Services.fs and expose the service via a new function:

In the C# project you can now access the service like this:

Changing the service

Now let’s see what happens if we change the service. Go to the Letters Codeunit in Dynamics NAV 2009 and add a second parameter (allLetters:Boolean) to the Capitalize method. After saving the Codeunit go back to the C# project and try to compile it again. As you can see the changes are directly reflected as a compile error.

In the next blog post I will show you how you can easily access a Dynamics NAV 2013 OData feed from F#.

Momentan (vom 18. bis 21. September) findet im Congress Centrum Mainz die BASTA! 2007 statt und ich habe heute im neu eingeführten “Business Solutions”-Track einen Vortrag über die Programmierung mit Microsoft Dynamics Nav gehalten. Die Slides zum Vortrag werden demnächst auf der Konferenz-CD und auf dem Navision Blog erhältlich sein.

Desweiteren ist Jens als Pressevertreter für den Navision Blog akkreditiert und wird von seinen Eindrücken auf der BASTA! berichten.

Weitere Infos zur BASTA findet man auch im BASTA-Blog.