VB.Net Tutorial/GUI/Controls

Add Label to a form

Imports System.Windows.Forms
public class AddNewLabelToForm
   public Shared Sub Main
        Application.Run(New Form1)
   End Sub
End class

Public Class Form1
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Dim lbl As New Label
        lbl.SetBounds(10, 50, 100, 25)
        lbl.Text = "Hello World!"
        Me.Controls.Add(lbl)
    End Sub
End Class
<Global.Microsoft.VisualBasic.rupilerServices.DesignerGenerated()> _
Partial Public Class Form1
    Inherits System.Windows.Forms.Form
    "Form overrides dispose to clean up the component list.
    <System.Diagnostics.DebuggerNonUserCode()> _
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing AndAlso components IsNot Nothing Then
            components.Dispose()
        End If
        MyBase.Dispose(disposing)
    End Sub
    "Required by the Windows Form Designer
    Private components As System.ruponentModel.IContainer
    "NOTE: The following procedure is required by the Windows Form Designer
    "It can be modified using the Windows Form Designer.  
    "Do not modify it using the code editor.
    <System.Diagnostics.DebuggerStepThrough()> _
    Private Sub InitializeComponent()
        Me.SuspendLayout()
        "
        "Form1
        "
        Me.AutoScaleDimensions = New System.Drawing.SizeF(6.0!, 13.0!)
        Me.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font
        Me.ClientSize = New System.Drawing.Size(292, 273)
        Me.Name = "Form1"
        Me.Text = "Form1"
        Me.ResumeLayout(False)
    End Sub
End Class

Add TextBox to Form in code

Imports System.Windows.Forms
public class AddTextBoxForm
   public Shared Sub Main
        Application.Run(New Form1)
   End Sub
End class

Public Class Form1
    Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        Dim dynamicText As TextBox = Nothing
        dynamicText = New Windows.Forms.TextBox
        dynamicText.Name = "TimeTextBox"
        dynamicText.Location = New System.Drawing.Point(8, 8)
        dynamicText.Size = New System.Drawing.Size(232, 20)
        dynamicText.TabIndex = 0
        Me.Controls.Add(dynamicText)
        Dim theTextBox As TextBox
        theTextBox = Me.Controls("TimeTextBox")
        If (theTextBox IsNot Nothing) Then
            theTextBox.Text = Now.ToLongTimeString()
        End If
    End Sub
End Class

<Global.Microsoft.VisualBasic.rupilerServices.DesignerGenerated()> _
Partial Class Form1
    Inherits System.Windows.Forms.Form
    "Form overrides dispose to clean up the component list.
    <System.Diagnostics.DebuggerNonUserCode()> _
    Protected Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing AndAlso components IsNot Nothing Then
            components.Dispose()
        End If
        MyBase.Dispose(disposing)
    End Sub
    "Required by the Windows Form Designer
    Private components As System.ruponentModel.IContainer
    "NOTE: The following procedure is required by the Windows Form Designer
    "It can be modified using the Windows Form Designer.  
    "Do not modify it using the code editor.
    <System.Diagnostics.DebuggerStepThrough()> _
    Private Sub InitializeComponent()
        Me.SuspendLayout()
        "
        "Form1
        "
        Me.AutoScaleDimensions = New System.Drawing.SizeF(6.0!, 13.0!)
        Me.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font
        Me.ClientSize = New System.Drawing.Size(260, 76)
        Me.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedSingle
        Me.MaximizeBox = False
        Me.Name = "Form1"
        Me.Text = "Dynamic Controls"
        Me.ResumeLayout(False)
    End Sub
End Class

Add the Button control to the Form Controls collection

imports System
imports System.Drawing
imports System.Windows.Forms
public class ControlParent : inherits Form
  Private WithEvents btn as Button
  public sub New()
    btn = new Button()
    btn.Location = new Point(50,50)
    btn.Size = new Size(100,23)
    btn.Text = "Relationships"
    Controls.Add(btn)
    btn.Parent = me
  end sub
  public shared sub Main() 
    Application.Run(new ControlParent())
  end sub
  private sub btn_Click(ByVal sender as object,ByVal e as EventArgs) Handles btn.Click
    Console.WriteLine("Button Parent:  " + btn.Parent.ToString())
    Console.WriteLine("Button HasChildren:  " + btn.HasChildren.ToString())
    Console.WriteLine("TopLevelControl:  " + btn.TopLevelControl.ToString())
    Console.WriteLine("Form HasChildren:  " + me.HasChildren.ToString())
    Console.WriteLine("Form Controls Count:  " + me.Controls.Count.ToString())
  end sub
end class

Cast event sender to control

Option Strict On
Imports System.Drawing
Imports System.Windows.Forms
Public Class Form1 : Inherits Form
   " Instantiate buttons
   Public WithEvents btnOK As New Button()
   Public WithEvents btnCancel As New Button()
   Public WithEvents btnQuit As New Button()
   
   " Application entry point
   Public Shared Sub Main()
      Dim frm As New Form1()
      frm.ShowDialog()
   End Sub
   
   " Class constructor
   Public Sub New()
      MyBase.New()
      " Define button sizes and locations
      Me.btnOK.Location = New Point(100, 50)
      Me.btnOK.Size = New Size(100, 50)
      Me.btnOK.Text = "OK"
      Me.btnOK.DialogResult = System.Windows.Forms.DialogResult.OK
      Me.btnCancel.Location = New Point(100, 125)
      Me.btnCancel.Size = New Size(100, 50)
      Me.btnCancel.Text = "Cancel"
      Me.btnCancel.DialogResult = System.Windows.Forms.DialogResult.Cancel
      
      Me.btnQuit.Location = New Point(100, 200)
      Me.btnQuit.Size = New Size(100, 50)
      Me.btnQuit.Text = "Exit"
      Me.btnQuit.DialogResult = System.Windows.Forms.DialogResult.Abort
      " Define form controls and caption
      Me.Controls.Add(btnOK)
      Me.Controls.Add(btnCancel)
      Me.Controls.Add(btnQuit)
      Me.Text = "Button Click Events"
   End Sub
   
   " Event handler for all three buttons
   Private Sub ButtonClicked(ByVal sender As System.Object, _
                             ByVal e As System.EventArgs) _
           Handles btnOK.Click, btnCancel.Click, btnQuit.Click
      If TypeOf sender Is Button Then
         Dim btn As Button = DirectCast(sender, Button)
         If btn.Name = "btnOK" Then
            Console.WriteLine("btnOK")
         ElseIf btn.Name = "btnCancel" Then
            Console.WriteLine("Cancel")
            Exit Sub
         Else 
            Me.Close()
         End If
      Else
         Throw New ArgumentException( _
               "The event was raised by an invalid object.")
      End If
   End Sub
End Class

Check Control type

Option Strict On
Imports System.Drawing
Imports System.Windows.Forms
Public Class Form1 : Inherits Form
   " Instantiate buttons
   Public WithEvents btnOK As New Button()
   Public WithEvents btnCancel As New Button()
   Public WithEvents btnQuit As New Button()
   
   " Application entry point
   Public Shared Sub Main()
      Dim frm As New Form1()
      frm.ShowDialog()
   End Sub
   
   " Class constructor
   Public Sub New()
      MyBase.New()
      " Define button sizes and locations
      Me.btnOK.Location = New Point(100, 50)
      Me.btnOK.Size = New Size(100, 50)
      Me.btnOK.Text = "OK"
      Me.btnOK.DialogResult = System.Windows.Forms.DialogResult.OK
      Me.btnCancel.Location = New Point(100, 125)
      Me.btnCancel.Size = New Size(100, 50)
      Me.btnCancel.Text = "Cancel"
      Me.btnCancel.DialogResult = System.Windows.Forms.DialogResult.Cancel
      
      Me.btnQuit.Location = New Point(100, 200)
      Me.btnQuit.Size = New Size(100, 50)
      Me.btnQuit.Text = "Exit"
      Me.btnQuit.DialogResult = System.Windows.Forms.DialogResult.Abort
      " Define form controls and caption
      Me.Controls.Add(btnOK)
      Me.Controls.Add(btnCancel)
      Me.Controls.Add(btnQuit)
      Me.Text = "Button Click Events"
   End Sub
   
   " Event handler for all three buttons
   Private Sub ButtonClicked(ByVal sender As System.Object, _
                             ByVal e As System.EventArgs) _
           Handles btnOK.Click, btnCancel.Click, btnQuit.Click
      If TypeOf sender Is Button Then
         Dim btn As Button = DirectCast(sender, Button)
         If btn.Name = "btnOK" Then
            Console.WriteLine("btnOK")
         ElseIf btn.Name = "btnCancel" Then
            Console.WriteLine("Cancel")
            Exit Sub
         Else 
            Me.Close()
         End If
      Else
         Throw New ArgumentException( _
               "The event was raised by an invalid object.")
      End If
   End Sub
End Class

Hide a control

Imports System.Windows.Forms
public class HideControl
   public Shared Sub Main
        Application.Run(New Form1)
   End Sub
End class

Public Class Form1
    Public val1 As Integer
    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        If val1 = 1 Then
            Button1.Visible = False
            val1 = 0
            Button2.Text = "Button1 Hidden"
        Else
            Button1.Visible = True
            val1 = 1
            Button2.Text = "Click Button2 to hide button1"
        End If
    End Sub
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
    End Sub
End Class

<Global.Microsoft.VisualBasic.rupilerServices.DesignerGenerated()> _
Partial Class Form1
    Inherits System.Windows.Forms.Form
    "Form overrides dispose to clean up the component list.
    <System.Diagnostics.DebuggerNonUserCode()> _
    Protected Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing AndAlso components IsNot Nothing Then
            components.Dispose()
        End If
        MyBase.Dispose(disposing)
    End Sub
    "Required by the Windows Form Designer
    Private components As System.ruponentModel.IContainer
    "NOTE: The following procedure is required by the Windows Form Designer
    "It can be modified using the Windows Form Designer.  
    "Do not modify it using the code editor.
    <System.Diagnostics.DebuggerStepThrough()> _
    Private Sub InitializeComponent()
        Me.Button1 = New System.Windows.Forms.Button
        Me.Button2 = New System.Windows.Forms.Button
        Me.SuspendLayout()
        "
        "Button1
        "
        Me.Button1.Location = New System.Drawing.Point(105, 65)
        Me.Button1.Margin = New System.Windows.Forms.Padding(4, 4, 4, 4)
        Me.Button1.Name = "Button1"
        Me.Button1.Size = New System.Drawing.Size(253, 40)
        Me.Button1.TabIndex = 0
        Me.Button1.Text = "Button1"
        Me.Button1.UseVisualStyleBackColor = True
        Me.Button1.Visible = False
        "
        "Button2
        "
        Me.Button2.Location = New System.Drawing.Point(105, 162)
        Me.Button2.Margin = New System.Windows.Forms.Padding(4, 4, 4, 4)
        Me.Button2.Name = "Button2"
        Me.Button2.Size = New System.Drawing.Size(253, 41)
        Me.Button2.TabIndex = 1
        Me.Button2.Text = "click Button2 to hide button1"
        Me.Button2.UseVisualStyleBackColor = True
        "
        "Form1
        "
        Me.AutoScaleDimensions = New System.Drawing.SizeF(8.0!, 15.0!)
        Me.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font
        Me.ClientSize = New System.Drawing.Size(473, 300)
        Me.Controls.Add(Me.Button2)
        Me.Controls.Add(Me.Button1)
        Me.Margin = New System.Windows.Forms.Padding(4, 4, 4, 4)
        Me.Name = "Form1"
        Me.Text = "Form1"
        Me.ResumeLayout(False)
    End Sub
    Friend WithEvents Button1 As System.Windows.Forms.Button
    Friend WithEvents Button2 As System.Windows.Forms.Button
End Class

Read and Save controls on a form to a file

Option Strict On
Imports System.IO
Imports System.Drawing
Imports System.Drawing.Drawing2D
Imports System.Windows.Forms
public class SaveReadControlsFile
   public Shared Sub Main
        Application.Run(New Form1)
   End Sub
End class

Public Class Form1
    Inherits System.Windows.Forms.Form
#Region " Windows Form Designer generated code "
    Public Sub New()
        MyBase.New()
        "This call is required by the Windows Form Designer.
        InitializeComponent()
        "Add any initialization after the InitializeComponent() call
    End Sub
    "Form overrides dispose to clean up the component list.
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing Then
            If Not (components Is Nothing) Then
                components.Dispose()
            End If
        End If
        MyBase.Dispose(disposing)
    End Sub
    Friend WithEvents Panel1 As System.Windows.Forms.Panel
    Friend WithEvents RichTextBox1 As System.Windows.Forms.RichTextBox
    Friend WithEvents ColorDialog1 As System.Windows.Forms.ColorDialog
    Friend WithEvents FontDialog1 As System.Windows.Forms.FontDialog
    Friend WithEvents SaveFileDialog1 As System.Windows.Forms.SaveFileDialog
    Friend WithEvents OpenFileDialog1 As System.Windows.Forms.OpenFileDialog
    Friend WithEvents btnChangeColor As System.Windows.Forms.Button
    Friend WithEvents btnChangeFont As System.Windows.Forms.Button
    Friend WithEvents btnSaveRTF As System.Windows.Forms.Button
    Friend WithEvents btnOpenRTF As System.Windows.Forms.Button
    Friend WithEvents btnWriteControls As System.Windows.Forms.Button
    Friend WithEvents btnReadControls As System.Windows.Forms.Button
    Friend WithEvents TextBox1 As System.Windows.Forms.TextBox
    Friend WithEvents TextBox2 As System.Windows.Forms.TextBox
    Friend WithEvents TextBox3 As System.Windows.Forms.TextBox
    "Required by the Windows Form Designer
    Private components As System.ruponentModel.IContainer
    "NOTE: The following procedure is required by the Windows Form Designer
    "It can be modified using the Windows Form Designer.  
    "Do not modify it using the code editor.
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        Me.Panel1 = New System.Windows.Forms.Panel()
        Me.RichTextBox1 = New System.Windows.Forms.RichTextBox()
        Me.ColorDialog1 = New System.Windows.Forms.ColorDialog()
        Me.FontDialog1 = New System.Windows.Forms.FontDialog()
        Me.SaveFileDialog1 = New System.Windows.Forms.SaveFileDialog()
        Me.OpenFileDialog1 = New System.Windows.Forms.OpenFileDialog()
        Me.btnChangeColor = New System.Windows.Forms.Button()
        Me.btnChangeFont = New System.Windows.Forms.Button()
        Me.btnSaveRTF = New System.Windows.Forms.Button()
        Me.btnOpenRTF = New System.Windows.Forms.Button()
        Me.btnWriteControls = New System.Windows.Forms.Button()
        Me.btnReadControls = New System.Windows.Forms.Button()
        Me.TextBox1 = New System.Windows.Forms.TextBox()
        Me.TextBox2 = New System.Windows.Forms.TextBox()
        Me.TextBox3 = New System.Windows.Forms.TextBox()
        Me.Panel1.SuspendLayout()
        Me.SuspendLayout()
        "
        "Panel1
        "
        Me.Panel1.Controls.AddRange(New System.Windows.Forms.Control() {Me.btnReadControls, Me.btnWriteControls, Me.btnOpenRTF, Me.btnSaveRTF, Me.btnChangeFont, Me.btnChangeColor})
        Me.Panel1.Dock = System.Windows.Forms.DockStyle.Bottom
        Me.Panel1.Location = New System.Drawing.Point(0, 222)
        Me.Panel1.Name = "Panel1"
        Me.Panel1.Size = New System.Drawing.Size(656, 64)
        Me.Panel1.TabIndex = 0
        "
        "RichTextBox1
        "
        Me.RichTextBox1.Location = New System.Drawing.Point(16, 8)
        Me.RichTextBox1.Name = "RichTextBox1"
        Me.RichTextBox1.Size = New System.Drawing.Size(336, 176)
        Me.RichTextBox1.TabIndex = 1
        Me.RichTextBox1.Text = "Mr. and Mrs. Dursley, of number four, Privet Drive, were proud to say that they w" & _
        "ere perfectly normal, thank you very much."
        "
        "btnChangeColor
        "
        Me.btnChangeColor.Location = New System.Drawing.Point(24, 24)
        Me.btnChangeColor.Name = "btnChangeColor"
        Me.btnChangeColor.Size = New System.Drawing.Size(88, 32)
        Me.btnChangeColor.TabIndex = 0
        Me.btnChangeColor.Text = "Change Color"
        "
        "btnChangeFont
        "
        Me.btnChangeFont.Location = New System.Drawing.Point(128, 24)
        Me.btnChangeFont.Name = "btnChangeFont"
        Me.btnChangeFont.Size = New System.Drawing.Size(88, 32)
        Me.btnChangeFont.TabIndex = 1
        Me.btnChangeFont.Text = "Change Font"
        "
        "btnSaveRTF
        "
        Me.btnSaveRTF.Location = New System.Drawing.Point(232, 24)
        Me.btnSaveRTF.Name = "btnSaveRTF"
        Me.btnSaveRTF.Size = New System.Drawing.Size(88, 32)
        Me.btnSaveRTF.TabIndex = 2
        Me.btnSaveRTF.Text = "Save RTF"
        "
        "btnOpenRTF
        "
        Me.btnOpenRTF.Location = New System.Drawing.Point(336, 24)
        Me.btnOpenRTF.Name = "btnOpenRTF"
        Me.btnOpenRTF.Size = New System.Drawing.Size(88, 32)
        Me.btnOpenRTF.TabIndex = 3
        Me.btnOpenRTF.Text = "Open RTF"
        "
        "btnWriteControls
        "
        Me.btnWriteControls.Location = New System.Drawing.Point(440, 24)
        Me.btnWriteControls.Name = "btnWriteControls"
        Me.btnWriteControls.Size = New System.Drawing.Size(88, 32)
        Me.btnWriteControls.TabIndex = 4
        Me.btnWriteControls.Text = "Write Controls"
        "
        "btnReadControls
        "
        Me.btnReadControls.Location = New System.Drawing.Point(544, 24)
        Me.btnReadControls.Name = "btnReadControls"
        Me.btnReadControls.Size = New System.Drawing.Size(88, 32)
        Me.btnReadControls.TabIndex = 5
        Me.btnReadControls.Text = "Read Controls"
        "
        "TextBox1
        "
        Me.TextBox1.Location = New System.Drawing.Point(400, 24)
        Me.TextBox1.Name = "TextBox1"
        Me.TextBox1.Size = New System.Drawing.Size(232, 20)
        Me.TextBox1.TabIndex = 2
        Me.TextBox1.Text = "TextBox1"
        "
        "TextBox2
        "
        Me.TextBox2.Location = New System.Drawing.Point(400, 68)
        Me.TextBox2.Name = "TextBox2"
        Me.TextBox2.Size = New System.Drawing.Size(232, 20)
        Me.TextBox2.TabIndex = 3
        Me.TextBox2.Text = "TextBox2"
        "
        "TextBox3
        "
        Me.TextBox3.Location = New System.Drawing.Point(400, 112)
        Me.TextBox3.Name = "TextBox3"
        Me.TextBox3.Size = New System.Drawing.Size(232, 20)
        Me.TextBox3.TabIndex = 4
        Me.TextBox3.Text = "TextBox3"
        "
        "Form1
        "
        Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
        Me.ClientSize = New System.Drawing.Size(656, 286)
        Me.Controls.AddRange(New System.Windows.Forms.Control() {Me.TextBox3, Me.TextBox2, Me.TextBox1, Me.RichTextBox1, Me.Panel1})
        Me.Panel1.ResumeLayout(False)
        Me.ResumeLayout(False)
    End Sub
#End Region
    Private Sub btnWriteControls_Click(ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles btnWriteControls.Click
        "Get a file
        Dim theFile As String
        SaveFileDialog1.InitialDirectory = Application.ExecutablePath
        SaveFileDialog1.DefaultExt = "hld" "custom format
        SaveFileDialog1.FileName = "myFile"
        SaveFileDialog1.Filter = "HLD Files (*.hld)|*.hld|All Files (*.*) | *.*"
        SaveFileDialog1.OverwritePrompt = True
        SaveFileDialog1.ShowDialog()
        theFile = SaveFileDialog1.FileName
        Dim fs As FileStream = New FileStream(theFile, FileMode.OpenOrCreate)
        Dim w As StreamWriter = New StreamWriter(fs)
        Dim c As Object
        For Each c In Me.Controls
         If TypeOf (c) Is TextBox Then
            Dim tbox As TextBox = CType(c, TextBox)
            w.WriteLine(tbox.Name & "=" & tbox.Text)
         End If
      Next
      w.Close()
      fs.Close()
    End Sub
    Private Sub btnReadControls_Click(ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles btnReadControls.Click
        Dim theFile As String
        OpenFileDialog1.InitialDirectory = Application.ExecutablePath
        OpenFileDialog1.DefaultExt = "hld" "custom format
        OpenFileDialog1.FileName = "myFile"
        OpenFileDialog1.Filter = "HLD Files (*.hld)|*.hld|All Files (*.*) | *.*"
        OpenFileDialog1.ShowDialog()
        theFile = OpenFileDialog1.FileName
        Dim fs As FileStream = New FileStream(theFile, FileMode.Open)
        Dim r As StreamReader = New StreamReader(fs)
        Dim c As Object
        Dim tmpArray() As String
        For Each c In Me.Controls
         If TypeOf (c) Is TextBox Then
            Dim tbox As TextBox = CType(c, TextBox)
            tmpArray = Split(r.ReadLine(), "=")
            If tbox.Name = tmpArray(0) Then
               tbox.Text = tmpArray(1)
            End If
         End If
      Next
        r.Close()
    End Sub
End Class

Set Control Parent

imports System
imports System.Drawing
imports System.Windows.Forms
public class ControlParent : inherits Form
  Private WithEvents btn as Button
  public sub New()
    btn = new Button()
    btn.Location = new Point(50,50)
    btn.Size = new Size(100,23)
    btn.Text = "Relationships"
    Controls.Add(btn)
    btn.Parent = me
  end sub
  public shared sub Main() 
    Application.Run(new ControlParent())
  end sub
  private sub btn_Click(ByVal sender as object,ByVal e as EventArgs) Handles btn.Click
    Console.WriteLine("Button Parent:  " + btn.Parent.ToString())
    Console.WriteLine("Button HasChildren:  " + btn.HasChildren.ToString())
    Console.WriteLine("TopLevelControl:  " + btn.TopLevelControl.ToString())
    Console.WriteLine("Form HasChildren:  " + me.HasChildren.ToString())
    Console.WriteLine("Form Controls Count:  " + me.Controls.Count.ToString())
  end sub
end class

Use Constrol"s Tag

imports System
imports System.Drawing
imports System.Windows.Forms
public class Tags : inherits Form
  private lbl as Label
  public sub New()
    Size = new Size(300,200)
    lbl = new Label()
    lbl.Text = "Label..."
    lbl.AutoSize = true
    lbl.Parent = me
    lbl.Location = new Point(10,10)
    dim theEnum as new FontStyle()
    dim theStyles as FontStyle() = CType([Enum].GetValues(theEnum.GetType()), FontStyle())
    dim i as integer = 1
    dim style as FontStyle
    for each style in theStyles
      dim btn as new Button()
      btn.Parent = me
      btn.Location = new Point(25,25 * i)
      btn.Size = new Size(75,20)
      btn.Text = style.ToString()
      btn.Tag = style
      AddHandler btn.Click, AddressOf btn_Click
      i += 1
    next
  end sub
  public shared sub Main() 
    Application.Run(new Tags())
  end sub
  private sub btn_Click(ByVal sender as object,ByVal e as EventArgs)
    dim btn as Button = CType(sender, Button)
    dim fs as FontStyle = CType(btn.Tag, FontStyle)
    lbl.Font = new Font(lbl.Font, fs)
  end sub
end class