Changing the Properties of a Data Class Using an Operation

This document provides information on how to use an operation to change the properties (fields) of a data class from another data class.

The development process described below demonstrates how to add a simple script to a data class (MYCLASS1) to create an operation called from a different data class (MYCLASS2).

1. Open your data class (MYCLASS1).
2. In the Methods block of the Methods tab:
   1. Enter a new method code (MYMETH1) in the Code field.
   2. Enter a description for the method in the Description field.
   3. Select the appropriate return type in the Return type field.
   4. Select the Operation check box. This automatically generates the keys in the Keys block.
3. In the Parameters block, enter the parameters (MYPARAM1) that need to be passed.
4. In the Scripts block of the General tab:
   1. Select the appropriate type for your script in the Type field.
   2. Accept the default code displayed in the Scripts field. It is automatically generated using the class code and the script type. You can also manually enter a unique code.
   3. Accept the numeric value displayed in the Running order field. It is automatically generated to control the order in which the $PROPERTIES and $METHODS labels are called in the event. You can also manually enter the running order.
5. Click the Actions button of your script, and click Processing editor. Enter the source code below.
   Note: This example uses the key passed in the Keys block of the Methods tab to read the current context from MYCLASS1, and then update the property (PROP1) using parameter MYPARAM1.
   

   $Structure MYCLASS1
   ##########################################
   #             METHODS                    #
   ##########################################
   $METHODS
     Case CURPTH
       When ""
           Case ACTION
              When "MYMETHOD" Gosub MYMETHOD  # Update MYPROP1 method 
           Endcase  
     Endcase
   Return
   # Update MYPROP1 using MYPRAM1 which is passed
   # KEY1 and MYPARM1 are passed and used in this operation
   $MYMETHOD
       # Use standard method CRUD to read MYCLASS1
       ASTATUS=fmet THIS.AREAD(KEY1) 
       If ASTATUS<>[V]CST_AOK 
         ARET_VALUE= CST_AFALSE
         Return
       Endif
       # Update PROP1 using MYPARM1
       THIS.PROP1 = MYPARM1
       # Update MYCLASS1
       ASTATUS=fmet THIS.AUPDATE
       If ASTATUS<>[V]CST_AOK # check status after update
          ARET_VALUE= CST_AFALSE
         Return
       Endif
   ARET_VALUE= CST_ATRUE 
   Return

6. Once the operation has been created, it must be called from data class MYCLASS2, or from any other data class.
   Add the following code to call MYMETHOD, which was defined above.
   

   ##############################################
   #  Data Class -  MYCLASS2                    #
   ##############################################
   ##############################################
   #                METHODS                     #
   ##############################################
   $METHODS
     Case CURPRO
       When ""
         Case ACTION
           When "AINSERT_AFTER" : Gosub AINSERT_AFTER
         Endcase
     Endcase
   Return
   # Action After insert
   $AINSERT_AFTER
       # Declaration new instance of MYCLASS2 data class
       Local Instance MYCLASS Using C_MYCLASS2
       MYCLASS = NewInstance C_MYCLASS2 AllocGroup Null
       ASTATUS=fmet MYCLASS.MYMETHOD(KEYID,MYPARM1)
       If ASTATUS<>[V]CST_ATRUE
         ASTATUS = fmet THIS.ASETERROR ("", "Not updated.", [V]CST_AERROR)    
       Endif
       # Free instances
       FreeGroup MYCLASS
   Return

7. Save your script.
8. Save and validate your data class.