Handling exceptions with try functions

The TryFunction property has been introduced to C/AL to handle exceptions thrown by .NET objects. It allows NAV application developers to catch exceptions and handle them the way the try...catch statement would in C#.

How to do it...

The following example explains how to declare a try function and catch exceptions from .NET objects.

1. To illustrate why we need the TryFunction attribute at all, let's create a codeunit with a function that will fail and throw a .NET exception. Let's call the GetDataFromRemoteSource function and suppose it is intended to load data from some web resource:

           HttpWebRequest := HttpWebRequest.Create('http://unknown'); 
           HttpWebResponse := HttpWebRequest.GetResponse; 
   

2. In the codeunit, the OnRun trigger will call the function:

           GetDataFromRemoteSource; 
   

   Then save and run the codeunit. The function fails, as expected:

   

3. This exception interrupts code execution and might frighten the user with the technical details...