Category Archives: NAV2017

Anti Pattern – TODAY function

One of the oldest features in C/AL and the AL code before that is the TODAY function. It will return the current date from the local computer.

A close friend of TODAY is WORKINGDATE. Working Date is the concept of setting “today” to be something else.

When working with entering data, the ease of type t in a date field for today, and w for working date are good for entering data.

But what about when you’re using TODAY (or WORKINGDATE) in your code?

Yesterday I came across an example in one of our old products:


Depending on the current date when the user pressed Post, different things would be posted.

It got me thinking, when is the use of TODAY appropriate in code?

The first valid use case would be to add a timestamp to records, field like “Modified Date, “Created Date”, “Approved Date”. Fields where you are recording the date of a user action.

In most other cases, you should use WORKINGDATE to give your users a chance to control the flow. And if actions in your code depend on Dates – let the user know about this.

Do you have other examples of the bad or good use of TODAY?

Inheritance security rules violated by type: Microsoft.Dynamics.Nav

If you get the following error:

Unhandled Exception: System.TypeLoadException: Inheritance security rules violated by type: 'Microsoft.Dynamics.Nav.WindowsServices.NavServerWindowsService'. Derived types must either match the security accessibility of the base type or be less accessible.
   at Microsoft.Dynamics.Nav.WindowsServices.DynamicsNavServer.Main(String[] args)

Then you have properly (as I did) updated your service tier with files from a zip file, that Windows Server 2012 have decided that are unsafe and need to be blocked. I got the error after a quick update of Microsoft Dynamics NAV 2017 to CU4.

The solution is easy, fire up PowerShell, and run the following command in the folders where you copied files:

dir -Recurse | Unblock-File

Then everything should work again 🙂

MediaSet fields in Queries..

When designing queries in Dynamics NAV you’ll get an error i CSide if you include a BLOB field, but no error if you include a MediaSet field. At runtime, you’ll get this strange error:

Unable to compare operands of type NSMediaSetWrapper with NavMediaDescriptionCollection.

Remove your MediaSet field from the Query Object and everything works again.

Att Microsoft: Perhaps expand the BLOB check in FINSQL.EXE to include MediaSet fields also 🙂

Blog entry to serve as hit for googling this error