How to process child collection rows

This ‘How-to’ provides information on how to process rows in a child collection.

The following development process demonstrates how to set an attribute of a property on all the rows in a child class.

Code to process rows in a child collection should go under the 'CURPTH' class path for the corresponding child collection, rather than under the main class. For example:

• If the class path is the child class (CURPTH = "[child class]"), the supervisor executes these events once per collection row:

  $METHODS
  
  
    Case CURPTH
      When "[child class]"
        Case ACTION
          When "AREAD_AFTER"
            Gosub ACTIVATE_FIELDS
        Endcase
    Endcase
  Return

  
  To set an attribute of a property on all the rows in the child class:

  $ACTIVATE_FIELDS
    ASTATUS = fmet this.ASETATTRIBUTE("PROPERTY",...
  Return

• If the class path is the main class (CURPTH = "" for example, blank = main class), the code is complex. The supervisor executes these events once for the entire entity:

  $METHODS
  
  
    Case CURPTH
      When ""
        Case ACTION
          When "AREAD_AFTER"
            Gosub ACTIVATE_FIELDS
          Endcase
    Endcase
  Return

  
  To set an attribute of a property on all the rows in the child class, a loop must be coded to iterate through each row in the corresponding child collection. Note that CHILD(I) might not exist and that deleted lines are still present (this explains the condition in the loop):

  $ACTIVATE_FIELDS
    For I = 1 To maxtab(this.CHILD)
      If this.CHILD(I)<>null and find(this.ASTALIN,[V]CST_ADEL,[V]CST_ANEWDEL)=0        
        ASTATUS = fmet this.CHILD(I).ASETATTRIBUTE("PROPERTY",...
      Endif
    Next
  Return

It is recommended to use the first method to avoid unnecessary loops and avoid dealing with indexes in a collection.