Differences in the Development Environments

Coming from the Dynamics NAV Development Environment and C/SIDE, there are some differences and optimizations that you should familiarize yourself with. The following sections go through these changes.

Data types

C/SIDE AL Language Development Environment
Dates are parsed based on culture settings. Locale independent and supports only: yyyy-mm-ddD.
Boolean values could be expressed as yes/no. Boolean values are expressed as true/false.
For tables, integers could allow decimal values. For example, 5.0 converts to an integer, 5.4 throws an error at runtime. For tables, Min, Max, InitValue numbers with a fraction are expressed as decimal, thus they are not a valid integer data type.
The largest constant integer could be 999999999999999. Transforms to 999'999'999'999'999.0, a decimal value. In AL, this can be expressed as 999999999999999.0 or 999999999999999L.

Syntax updates

C/SIDE AL Language Development Environment
The token for multilanguage comment is @@@. A multilanguage comment is marked with Comment.
Supports TryFunction on code developed in C/SIDE. Supports calling referenced TryFunctions from W1.

Several properties have been renamed, to mention some:

C/SIDE AL Language Development Environment
AutoFormatExpr AutoFormatExpression
DataCaptionExpr DataCaptionExpression
Layout GridLayout
ProviderID Provider


Property values are considered as syntax elements; thus they should follow the standard AL escaping rules.

Multilanguage properties

With the introduction of .xliff files, the ML properties, such as CaptionML and TooltipML will be deprecated in a later version. Use the equivalent properties instead, such as Caption and Tooltip, then make sure the manifest is set up to generate the /Translations folder and use the generated .xliff files for translations of the extension. For more information, see Working with Translation Files.


The ActionContainer elements in AL have been renamed; the following table lists the renamed elements:

C/SIDE AL Language Development Environment
ActionItems Processing
ActivityButtons Sections
HomeItems Embedding
NewDocumentItems Creation
RelatedInformation Navigation
Reports Reporting

For instance, area(Sections) can be defined inside the actions section of the page.

Likewise, Container and ContainerType elements in C/SIDE have been renamed to area(Content|FactBoxes|RoleCenter) and can be defined inside the layout section of the page.


For backwards compatibility we continue to support adding non-part pages as parts. We do, however, recommend that you redesign your page to only use Card part or List part, as we may remove support in a future update.

For syntax examples, see Page Object.


Controls, actions, and methods names must be unique on pages. In C/SIDE, you could create a Part control with the same name as a method, which would give you an error at runtime. This is now prevented, by disallowing duplicates. Similarly, trigger and trigger event names are disallowed on matching application object types. Likewise, actions and fields could have same names before, but that would have prevented page testability access, and will now throw a compilation error.


Name on Controls and Actions on Pages is now mandatory.

Property dependencies

Some properties require that you set another property. An example is PromotedCategory, which requires that you have enabled the property Promoted. The following table lists some of the properties that have this dependency.

Property Depends on the property...
PromotedCategory Promoted
PromotedIsBig Promoted
ValidateTableRelation TableRelation
SourceTableTemporary SourceTable
RunPageMode RunObject

Limited functionality

The InitValue property of type Duration is not allowed in new development environment.
The InitValue of type DateTime only allows for the value 0DT.

See Also

Developing Extensions
Getting Started with AL
AL Development Environment