This section describes where to write C/AL code and how to reuse code.
For more information about how to use system-defined variables, see System-Defined Variables.
For more information about the most frequently used C/AL functions, see Essential C/AL Functions.
Where to Write C/AL Code
Almost every object in Microsoft Dynamics NAV contains triggers where you can add your C/AL code. Triggers exist for the following objects:
- Table fields
- Pages, including request pages
- Data items
You can initiate the execution of your C/AL code from the following:
- Menu items
- Any object that has an instantiation of the
object that contains C/AL code. An example of an instantiation is a
Note If the C/AL code is in a local function, then you cannot run it from another object.
Guidelines for Placing C/AL Code
We recommend the following guidelines for C/AL code:
- In general, put the code in codeunits instead
of on the object on which it operates. This promotes a clean design
and provides the ability to reuse code. It also helps enforce
security. For example, typically users do not have direct access to
tables that contain sensitive data, such as the General Ledger
Entry table, nor do they have permission to modify objects. If
you put the code that operates on the general ledger in a codeunit,
give the codeunit access to the table, and give the user permission
to execute the codeunit, then you will not compromise the security
of the table and the user will be able to access the
- If you must put code on an object instead of
in a codeunit, then put the code as close as possible to the object
on which it operates. For example, put code that modifies records
in the triggers of the table fields.
Reusing code makes developing applications both faster and easier. More importantly, if you organize your C/AL code as suggested, your applications will be less prone to errors. By centralizing the code, you will not unintentionally create inconsistencies by performing the same calculation in many places, for example, in several triggers that have the same table field as their source expression. If you have to change the code, you could either forget about some of these triggers or make a mistake when you modify one of them.