VB.NET Windows Forms

Introduction

Windows Forms (WinForms) provides a rich set of managed UI components for building desktop applications with the Visual Basic .NET language. This documentation covers the core concepts, common controls, event handling, layout strategies, and best practices.

Getting Started

Create a new Windows Forms project in Visual Studio using the VB Windows Forms App template. The IDE generates a Form1.vb class that inherits from System.Windows.Forms.Form.

Public Class Form1
    Inherits System.Windows.Forms.Form

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Text = "Hello, Windows Forms!"
    End Sub
End Class

This simple form displays a title bar with the text Hello, Windows Forms!.

Key Concepts

• Controls: Visual elements like Button, TextBox, Label, etc.
• Events: User interactions (click, key press) are exposed as events you can handle.
• Layout: Use containers such as TableLayoutPanel or FlowLayoutPanel for responsive designs.
• Data Binding: Bind controls to data sources for automatic UI updates.

Sample Application

The following example demonstrates a basic calculator with two input fields, a button, and a label that displays the result.

Public Class CalculatorForm
    Inherits Form

    Private txtA As New TextBox() With {.Location = New Point(20, 20), .Width = 80}
    Private txtB As New TextBox() With {.Location = New Point(110, 20), .Width = 80}
    Private btnAdd As New Button() With {.Text = "Add", .Location = New Point(200, 18)}
    Private lblResult As New Label() With {.AutoSize = True, .Location = New Point(20, 60)}

    Public Sub New()
        Text = "Simple Calculator"
        Controls.AddRange({txtA, txtB, btnAdd, lblResult})
        AddHandler btnAdd.Click, AddressOf OnAddClicked
    End Sub

    Private Sub OnAddClicked(sender As Object, e As EventArgs)
        Dim a, b As Double
        If Double.TryParse(txtA.Text, a) AndAlso Double.TryParse(txtB.Text, b) Then
            lblResult.Text = $"Result: {a + b}"
        Else
            lblResult.Text = "Invalid input."
        End If
    End Sub
End Class

Module Program
    
    Sub Main()
        Application.EnableVisualStyles()
        Application.Run(New CalculatorForm())
    End Sub
End Module