Operator # New
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Operator --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- ## Description Used to create New instances of objects at runtime. ## Usage ``` xojo objectReference = New ClassName [ (param1, param2,...) ] Var objectReference As New ClassName [ (param1, param2,...) ] ``` | Part | Type | Description | |-----------------|-----------------------------|----------------------------------------------------------------------------------------------| | objectReference | Must be a type of ClassName | Required. Variable/Property of type *ClassName*, its superclasses or implemented interfaces. | | ClassName | A class name | Required. Any available class with a non-private constructor. | ## Notes The `constructor` for a class is called whenever you create a New instance of it with the New statement. The New operator can appear as a modifier on a `Var` statement that creates a New object. This usage takes the place of two lines of code: The `Var` statement that creates the object and a separate New statement that instantiates the object. --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- ### Creating new instances of all other types of objects The New operator can be used to create a New instance of any type of class. The object reference must be defined as the class type, one of its superclasses or an interface that it implements. --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- ### Constructors When you create a New object, you will sometimes want to perform some sort of initialization on the object. The `constructor` is a mechanism for doing this. A class's constructor is the method that will be executed automatically when an instance of the class is created. You write a constructor for a custom class by creating a New method for the class and naming it "Constructor". The drop-down list for the Method name field suggests this name and the names of all other methods that can be overridden. There can be multiple overloaded constructors. When you create a constructor for any subclass, the Code Editor automatically inserts code that calls the constructor for its super class using the `Super` keyword. If there is more than one constructor, it inserts calls to all of them. This is because the subclass's constructor overrides its super class's constructor but the New subclass may not initialize itself correctly without a call to the super class's constructor. You can edit the inserted calls in the event that this assumption is incorrect. For example, this constructor creates a `DateTime` instance and sets it to the passed date. The parameters are year, month, and day. ``` xojo Var d As New DateTime(2025, 4, 15) ``` If the parameters were omitted, the New date would be set to the current date. ## Sample code This code creates and then displays a New instance of a `Window` called "AboutBox": ``` xojo Var w As AboutBox w = New AboutBox ``` --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- This code creates a New instance of a `DesktopMenuItem` called "WindowItem1": ``` xojo Var m As DesktopMenuItem m = New WindowItem1 ``` --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- This code creates a New instance of a `MessageDialog` box: ``` xojo Var d As New MessageDialog ``` --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- It is equivalent to the following two lines: ``` xojo Var d As MessageDialog d = New MessageDialog ``` --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- This code uses the `DesktopMenuItem` constructor to create a New menuitem in the Edit menu and assign it its Name property: ``` xojo Var EditPasteSpecial As New DesktopMenuItem("Paste Special...") EditMenu.AddMenuAt(5, EditPasteSpecial) ``` --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- This code creates a `DateTime` instance and sets it to 22 September, 2025, 9:15AM. ``` xojo Var d As New DateTime(2025, 9, 22, 9, 15, 0) ``` --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- The following code is from the example project "Drag and Drop Text" in the Examples folder. The main window consists of a `DesktopLabel` control and a `DesktopTextArea`. The user can drag the text in the `DesktopLabel` into the `DesktopTextArea`. This is not possible by default but the ability to drag the text is enabled by the code in the MouseDown event of the `DesktopLabel`. It is: ``` xojo Var d As DragItem d = New DragItem(Self, Me.Left, Me.Top, Me.Width, Me.Height) d.Text = Me.Value d.Drag ``` --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- The following code creates a New `FolderItem`. You can create a copy of a `FolderItem` by passing the `FolderItem` to be copied to the constructor. The result is a copy of the passed `FolderItem` rather than a reference to it. The following code creates a New `Picture` instance that has an alpha channel (i.e., a transparency parameter). ``` xojo Var width As Integer = 2000 Var height As Integer = 2000 ' Creates new picture Var pic As New Picture(width, height) ``` --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- This constructor creates a `Picture` object that will mirror the content that is drawn into a `DesktopCanvas` in its Paint event. ``` xojo p = New Picture(Canvas1.Width, Canvas1.Height) ``` ## Compatibility | | | |-----------------------|-----| | **Project Types** | All | | **Operating Systems** | All |
`Var` command; `Nil` datatype; `Constructor` concept