@P

Category: Objects

Syntax:
@P object.property = value

Sets the specified object's property to value.

If object belongs to a built-in class, value must be of the appropriate type for the property. Setting a property may cause side effects, depending on the implementation of the class; for example, changing a button's Caption property causes the caption to change on screen. object.property may refer to nested object-type properties: $label.Font.Name

If object belongs to a user-defined class, the effect of @p depends on the property definition and which object is invoking @p:

Write specifier	@p invoked by	Effect
Omitted	Any code	`value` stored in the object's property data
NoWrite	Any code	Nothing happens
Writer method	The object's own method	`value` stored in the object's property data
Writer method	Any method of another object, or any other code	Writer method invoked with $0 = `property`, $1- = `value`

When setting an event handler property, you should usually use @E instead.

Example:
@p $form.Caption = My Form
@p $button.Font.Style = [fsBold]

// validating property values with a writer method
Class TMyClass
  Public Property Count write SetCount
  
  Private Method SetCount
    if $IsNumeric($1)
      // this sets the property data directly
      @p $Self.Count = $1
    else
      MessageBox Numbers only please!
    endif
  EndMethod
EndClass

@l $obj = $new(TMyClass)
// this invokes the writer method
@p $obj.Count = 5
// displays the error message box
@p $obj.Count = Dracula
// still displays 5
MessageBox $prop($obj.Count)