How to load the value of a custom screen field

Sage X3 provides unlimited possibilities for screen customization - fields can be added to any screen and grid. But if we add a field that is not part of the main object table, we might need a bit of custom programming in order to load its value when the screen loads. Here is an example of how to do this (based on a forum question)

Suppose that in the Calls function (GESCLL) we want to add a field that will show the position of the selected contact in his organization. Like this:

The field we need is CNTFNC in the Contacts table. First we create the corresponding screen field in the Screens function (GESAMK), screen CLL0:

After we validate the screen, from the General tab we access the SPECLL file, where we enter the following code:

$ACTION
Case ACTION
    When "OUVRE" : Gosub OUVRE
    When "LIENS" : Gosub LIENS
    When Default
Endcase
Return

$OUVRE
If clalev([CNT])=0 : Local File CONTACT [CNT] : Endif
Return

$LIENS
Read [CNT]CNT0=1;[M:CLL0]CLLCMP;[M:CLL0]CLLCCN
If !fstat
    [M:CLL0]CNTFNC=[F:CNT]CNTFNC
Endif
Return

In the opening action OUVRE we make sure to open the CONTACT table, if it is not already opened. Then, in the action LIENS which is called on each screen update but before the screen is displayed, we read in the contact and, if there are no errors, assign his function in the organization (CNTFNC field) to our custom field of the same name.

You might need to logout/login before this custom development becomes active. Also, do not forget to save and compile the SPECLL file, as well as to validate the CLL0 screen.