With Microsoft Dynamics NAV 2017, you can use events to design the application to react to specific actions or behavior that occur, enabling you to separate customized functionality from the application business logic. Using events where customizations are usually made provides a lower cost of code modifications.
The principal is that you program events in the application to run customized behavior when they occur. In this example, we are going to develop the same customization to NAV – with and without use of Events subscriptions. The business requirement is to check to see if sales order margin is more than 20% at the time of posting.
To address this requirement in older versions of NAV, a NAV developer would insert custom code into codeunit 80 to execute additional business logic (for example check if order margin is above 20%). The end result was that the business user was satisfied – until they had to pay to have a developer merge that code into the next version of NAV.
In NAV 2017, a developer would address the same business requirement without modifying codeunit 80. In the example below, you will see that Microsoft has introduced events to NAV. The event in this case is OnBeforePostSalesDoc. A NAV developer would write a custom codeunit in the customer range (50000 -99999) and then subscribe to the event in CodeUnit 80. While NAV is executing codeunit 80, that event will check the custom codeunit and execute the business logic (in this case check for 20% margin).
The difference between these two approaches is not evident to the business user. However, the new approach eliminates the need to merge code in CodeUnit 80 when moving from version 2017 to a later version. The upgrade effort will be much faster, as standard NAV code is left unmodified.
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