Property Statement

A property, also called field or attribute, characterizes a given object or piece of information. Properties can be used to control access to data. It is common use to include instructions at setting or reading time of properties. Code can vary from simple assignment to complex context dependent routines. Using Get, Let or Set accessors enforces properties' consistency when necessary.

This statement requires Option Compatible to be placed before the executable program code in a module.

Sintaxi:

Diagrama d'extractes de propietat


         [Private | Public] Property Get name[char | As typename]
         End Property

Property Set Statement diagram


         [Private | Public] Property [Let | Set] name[char] [([Optional [ByRef | ByVal]]value[char | As typename])] [As typename]
         End Property

Paràmetres :

name: The property name.

argument: el valor que es passarà a la rutina que defineix Property.

Property setters often use a single argument. Multiple arguments are equally accepted.

fragment Argument

argument fragment


      {[Optional [ByRef|ByVal]]|ParamArray} argument {{As typename|char}[ = expression]|[()]As Variant}

Paràmetres

Optional: l'argument no és obligatori.

ByRef L'argument es passa per referència. ByRef és el predeterminat.

ByVal L'argument es passa per valor. El seu valor es pot modificar per la rutina anomenada.

char: caràcter de declaració del Tipus.

typename: Primitive data type name. Library or module defined types can also be specified.

= expressió Especifiqueu un valor predeterminat per a l'argument que coincideix amb el seu tipus declarat. Opcional és necessari per a cada argument que especifique un valor predeterminat.

ParamArray Usa ParamArray quan el nombre de paràmetres no està determinat. Un escenari típic és el d'una funció definida per l'usuari del Calc. L'ús del ParamArray hauria de limitar-se a l'últim argument d'una rutina.

UsingParamArray or = expression require Option Compatible to be placed before the executable program code in a module.

When using Option VBASupport 1, Optional arguments with no default value (= expression) are initialized according to their data type, except if Variant.

typename fragment

primitive data types fragment


      {Boolean|Byte|Currency|Date|Double|Integer|Long|Object|Single|String|Variant}

char fragment

type declaration caràcters


      { % | & | ! | # | $ | @ }

Exemples


      Option Compatible
      Sub Main
          ProductName = "Office"
          Print ProductName ' mostra «LibreOffice»
      End Sub
      
      Private _office As String
      Property Get ProductName As String
          ProductName = _office
      End Property
      Property Let ProductName(value As String)
          _office = "Libre"& value
      End Property

In the absence of Property Let or Property Set, Property Get helps define protected information, which can not be accidently altered by a foreign module:


      Option Compatible
      Public Property Get PathDelimiter As String ' variable només de lectura
          Static this As String
          If this = "" Then : Select Case GetGuiType()
              Case 1 : this = ";" ' Windows
              Case 4 : this = ":" ' Linux or macOS
              Case Else : Error 423 ' Property or method not defined: PathDelimiter
          End Select : End If
          PathDelimiter = this
      End Property ' read-only PathDelimiter
      
      Sub Main
          PathDelimiter = "un enunciat" ' no fa res
      End Sub

Use Let or Set when handling UNO services or class objects:


      Option Compatible
      Sub Main
          'Set anObject = CreateUnoService( "com.sun.star.frame.Desktop" )
          anObject = CreateUnoService( "com.sun.star.frame.Desktop" )
          Print anObject.SupportedServiceNames(0) ' displays "com.sun.star.frame.Frame"
      End Sub
      
      Property Get anObject As Object
          Set anObject = _obj
      End Property
      
      Private _obj As Object
      
      'Property Set anObject(value As Object)
          'Set _obj = value.CurrentFrame
      'End Property
      Property Let anObject(value As Object)
          Set _obj = value.CurrentFrame
      End Property

Conceptes bàsics quant a les subrutines

Using Procedures, Functions and Properties

Function Statement

Sub Statement

End, Exit statements

Opció ClassModule expressió

Expressió compatible amb opcions