How to change the properties of one data class from another data class using an operation @ L.V. Expertise X3

How to change the properties of one data class from another data class using an operation

This ‘How-to’ provides information on how to use an operation to change the properties (fields) of one data class from a different data class.

Operations are similar to methods:

Operations are stateless – within an operation, the current content is being ‘read’. For example, the class data is not yet available.
Methods are stateful – within a method, the current context is being ‘worked with’. For example, the properties within the class are already available.

The following development process demonstrates how to add a simple script to a given data class (MYCLASS1) to create on (MYCLASS1) an operation which is called from a different data class (MYCLASS2).

Open your data class (MYCLASS1).
Select the Methods tab >Methods block, and set the following field values:
Code: Enter a new method code (MYMETH1).
Description: Enter a description for the method.
Return type: Select an appropriate return type.
Operation: Select this option (yes). This will automatically generate the keys ( Keys block).
Enter parameters (MYPARAM1), which need to be passed ( Parameter definitions block).
Select the General tab >Scripts block, and set the following field values:
Type: Select a type appropriate for your script.
Scripts: Accept the displayed default code. This is automatically generated using the class code and script type. Alternatively, enter a unique code for your script.
Running order: Accept the displayed numeric value. This is automatically generated to control the order in which the '$PROPERTIES' and '$METHODS' labels are called in the event. Alternatively, enter the running order code for your script.
To add your script, right-click the Scripts code and select Processing editor from the selection menu. Enter the source code (see below):
Note: This example will use the key (Methods tab > Keys block) which is passed to read the current context from 'MYCLASS1', and then update the property (PROP1) using the parameter 'MYPARAM1', which is passed to PROP1.

$Structure MYCLASS1###########################################METHODS ###########################################$METHODSCase CURPTHWhen ""Case ACTIONWhen "MYMETHOD" Gosub MYMETHOD # Update MYPROP1 method Endcase EndcaseReturn# Update MYPROP1 using MYPRAM1 which is passed# KEY1 and MYPARM1 are passed and used in this operation$MYMETHOD# Use standard method CRUD to read MYCLASS1ASTATUS=fmet THIS.AREAD(KEY1) If ASTATUS<>[V]CST_AOK ARET_VALUE= CST_AFALSEReturnEndif# Update PROP1 using MYPARM1THIS.PROP1 = MYPARM1# Update MYCLASS1ASTATUS=fmet THIS.AUPDATEIf ASTATUS<>[V]CST_AOK # check status after updateARET_VALUE= CST_AFALSEReturnEndifARET_VALUE= CST_ATRUE Return

6. Once the operation has been created, the operation must be called from the data class 'MYCLASS2' or from any other data class. Add a similar code to the following. This calls 'MYMETHOD', which is defined above.

############################################### Data Class - MYCLASS2 ##############################################################################################METHODS ###############################################$METHODSCase CURPROWhen ""Case ACTIONWhen "AINSERT_AFTER" : Gosub AINSERT_AFTEREndcaseEndcaseReturn#Action After insert$AINSERT_AFTER# Declaration new instance of MYCLASS2 data classLocal Instance MYCLASS Using C_MYCLASS2MYCLASS = NewInstance C_MYCLASS2 AllocGroup NullASTATUS=fmet MYCLASS.MYMETHOD(KEYID,MYPARM1)If ASTATUS<>[V]CST_ATRUEASTATUS = fmet THIS.ASETERROR ("", "Not updated.", [V]CST_AERROR) Endif# Free instancesFreeGroup MYCLASSReturn

7. Save your script.

8. Save and validate your data class.

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