VP SET CUSTOM FUNCTIONS

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4D v19


VP SET CUSTOM FUNCTIONS ( vpAreaName ; formulaObj )

Parameter	Type	Description
vpAreaName	Text	4D View Pro area form object name
formulaObj	Object	Formula object

Description

The VP SET CUSTOM FUNCTIONS command designates the 4D formulas that can be called directly from 4D View Pro formulas. Because custom functions are not stored in the document, VP SET CUSTOM FUNCTIONS must be executed in the On Load form event.

The formulas specified by VP SET CUSTOM FUNCTIONS appear in a pop-up menu when the first letter of their name is entered. See Entering a Formula, a Function or a Reference.

Note: If VP SET CUSTOM FUNCTIONS is called multiple times for the same area, in the same session, only the last call is taken into account.

Pass the name of the 4D View Pro area in vpAreaName. If you pass a name that does not exist, an error is returned.

In the formulaObj parameter, pass an object containing the 4D formulas that can be called from 4D View Pro formulas as well as additional properties. Each customFunction property passed in formulaObj becomes the name of a function in the 4D View Pro area.

Property

Type

Description

<customFunction>

Object

Custom functions to define in 4D View Pro

formula

Object

4D formula object (mandatory). See Formula

parameters

Collection of objects

Collection of parameters (in the order they are defined in the formula)

[ ].name

Text

Name of parameter to display in 4D View Pro

[ ].type

Number

Type of the parameter. Supported types:

Constant
Is Boolean
Is date
Is longint
Is object
Is real
Is text
Is time

If type is omitted or if the default value (-1) is passed, the value is automatically sent with its type, except date or time values which are sent as an object (see Parameters section).

If type is Is object, the object has the same structure as the object returned by VP Get value.

summary

Text

Formula description to display in 4D View Pro

minParams

Number

Minimum number of parameters

maxParams

Number

Maximum number of parameters. Passing a number higher than the length of parameters allows declaring "optional" parameters with default type

WARNING

If a formula has the same name as a function defined by the VP SET ALLOWED METHODS command, the formula is created and the method ignored.
As soon as VP SET CUSTOM FUNCTIONS is called, the methods allowed by SET ALLOWED METHODS are ignored in the 4D View Pro area.
As soon as VP SET CUSTOM FUNCTIONS is called, the functions based upon SET TABLE TITLES and SET FIELD TITLES commands are ignored in the 4D View Pro area.

Example

You want to use formula objects in a 4D View Pro area to add numbers, retrieve a customer's last name and gender:

 Case of

    :(Form event code=On Load)

 

       var $o : Object

 

       $o:=New object

 

  // Define “addnum“ function from a method named "addnum"

       $o.addnum:=New object

       $o.addnum.formula:=Formula(addnum)

       $o.addnum.parameters:=New collection

       $o.addnum.parameters.push(New object("name";"num1";"type";Is longint))

       $o.addnum.parameters.push(New object("name";"num2";"type";Is longint))

 

  // Define “ClientLastName“ function from a database field

       $o.ClientLastName:=New object

       $o.ClientLastName.formula:=Formula([Customers]lastname)

       $o.ClientLastName.summary:="Lastname of the current client"

 

  // Define “label“ function from a 4D expression with one parameter

       $o.label:=New object

       $o.label.formula:=Formula(ds.Customers.get($1).label)

       $o.label.parameters:=New collection

       $o.label.parameters.push(New object("name";"ID";"type";Is longint))

 

  // Define “Title“ function from a variable named "Title"

       $o.Title:=New object

       $o.Title.formula:=Formula(Title)

 

       VP SET CUSTOM FUNCTIONS("ViewProArea";$o)

 

 end case