Structs (Visual Basic)

In Visual Basic, a Structure (or struct) is a value type that can contain data members and methods. Structures are useful for grouping related data without the overhead of a class.

Definition

A structure is declared using the Structure keyword and ends with End Structure. By default, structs are sealed and cannot be inherited.

Syntax

Structure StructName
    ' Fields
    Public field1 As DataType
    Private field2 As DataType

    ' Constructors
    Public Sub New(param1 As DataType, param2 As DataType)
        Me.field1 = param1
        Me.field2 = param2
    End Sub

    ' Methods
    Public Function ToString() As String
        Return $"{field1}, {field2}"
    End Function
End Structure

Example

The following example defines a Point structure that represents a coordinate in a two‑dimensional space.

Structure Point
    Public X As Integer
    Public Y As Integer

    Public Sub New(x As Integer, y As Integer)
        Me.X = x
        Me.Y = y
    End Sub

    Public Overrides Function ToString() As String
        Return $"({X}, {Y})"
    End Function
End Structure

Module Demo
    Sub Main()
        Dim p1 As New Point(10, 20)
        Dim p2 As Point = p1   ' Value copy
        p2.X = 30

        Console.WriteLine(p1)  ' (10, 20)
        Console.WriteLine(p2)  // (30, 20)
    End Sub
End Module

Remarks

• Structs are value types; assigning one struct to another creates a copy.
• They cannot inherit from other structs or classes, but they can implement interfaces.
• Use ReadOnly structures for immutable data.

Related Topics