New

Creates a new instance of a class.

The New keyword is used in three contexts:

In a declaration (Dim, Private, Public, or Static) written As New, to enable implicit object creation: a new instance is created on the first reference to the variable.
In a Set statement, to create a new instance of a class and assign the reference to a variable or property.
(twinBASIC) In a declaration’s initializer, = New, to create a new instance as the variable is declared. See Inline Initialization.

Syntax:

[ Dim | Private | Public | Static ] varname As New type
Set objectvar = New type [ ( arglist ) ]
[ Dim | Private | Public | Static ] varname As type = New type [ ( arglist ) ]

varname, objectvar: Name of the variable or property receiving the new object reference.
type: A class name or other creatable object type. New can’t be used to create new instances of any intrinsic data type (such as Long or String), and can’t be used to create dependent objects.
arglist: optional (twinBASIC) The arguments passed to the class’s Sub New constructor, separated by commas — New Dog("Rex"). The class must declare a Sub New whose parameters match; see Parameterized Class Constructors. The As New form takes no arguments: Dim d As New Dog("Rex") is a syntax error. So As New needs a class that can be created without arguments: one with a Sub New that takes none or whose parameters are all Optional (the object is created by calling Sub New with the default values), or one with a Class_Initialize. For a class whose only Sub New has required arguments, As New fails with TB5121, can’t use this type with As-New syntax as it doesn’t have a parameterless constructor. In BETA 1005, a Static variable in a module procedure can take them in an initializer only when the class is declared earlier in the project: Static d As Dog = New Dog("Rex") fails with TB5074 when Dog is declared later — in a file that comes later in the project, or lower in the same file. Dim with the same initializer, and a Static in a class method, compile in either order. So that the code does not depend on file order, declare the Static variable, then assign it with Set.

When New is used in a declaration, no instance is created at the point of declaration. Instead, an instance is created automatically the first time the variable is referenced after declaration. Each time the variable is set to Nothing and then referenced again, a new instance is created.

When New is used with Set, an instance is created immediately, and the reference is assigned to objectvar. If objectvar previously held a reference to another object, that reference is released when the new one is assigned.

When New is used in an initializer inside a procedure, the instance is created when execution reaches the declaration, not when the procedure starts.

Note

New cannot be used together with WithEvents in a declaration. To connect an event-aware object reference, declare the variable with WithEvents and assign it later with Set.

Example

Implicit creation via New in a declaration. The instance of Collection is created on first use, not at the Dim line.

Dim X As New Collection
' No instance exists yet.
X.Add "first" ' First reference - instance is created here.

Explicit creation via Set … = New. The instance is created at the Set line. This is the more common form, since the moment of construction is visible at the call site.

Dim Forms(1 To 4) As Form1
Dim i As Long
For i = 1 To 4
    Set Forms(i) = New Form1
Next i

(twinBASIC) Creation with constructor arguments. The class declares a Sub New that takes a name, and each New passes one. The class is Private because a public class whose only constructor takes arguments does not compile (TB5135).

Private Class Dog
    Private m_Name As String

    Public Sub New(ByVal Name As String)
        m_Name = Name
    End Sub

    Public Property Get Name() As String
        Name = m_Name
    End Property
End Class

Dim d As Dog = New Dog("Rex")   ' declared and created in one statement
Dim e As Dog
Set e = New Dog("Fido")         ' created by a Set statement

New

Example

See Also