Create Custom Button in Form

No need to Inherit from Button if you want a button with a completely custom appearance.
The following class defines a Custom Button which can be set as a forms AcceptButton or CancelButton, but which is inherited from Control rather than Button. It also includes a custom TypeEditor to allow selection of corners to be rounded.

Note: that this example needs a reference to System.Design.dll since it uses a custom TypeEditor

VB net Sample:

Imports System.ComponentModel
  Imports System.Security.Permissions
  Imports System.Drawing.Design
  Imports System.Windows.Forms.Design

  Namespace Dotnetrix.Samples.VB

  <Flags()> _
  Public Enum Corners
  None = 0
  TopLeft = 1
  TopRight = 2
  BottomLeft = 4
  BottomRight = 8
  All = TopLeft Or TopRight Or BottomLeft Or BottomRight
  End Enum

  Public Enum CustomButtonState
  [Normal] = 1
  [Hot]
  [Pressed]
  [Disabled]
  [Focused]
  End Enum

  Public Class CustomButton
  Inherits Control
  Implements IButtonControl

  Public Sub New()
  MyBase.New()
  Me.SetStyle(ControlStyles.Selectable Or ControlStyles.StandardClick Or ControlStyles.ResizeRedraw Or ControlStyles.AllPaintingInWmPaint Or ControlStyles.DoubleBuffer Or ControlStyles.UserPaint Or ControlStyles.SupportsTransparentBackColor, True)
  End Sub

  #Region " Private Instance Variables "

  Private m_DialogResult As DialogResult
  Private m_IsDefault As Boolean

  Private m_CornerRadius As Int32 = 8
  Private m_RoundCorners As Corners
  Private m_ButtonState As CustomButtonState = CustomButtonState.Normal

  Private m_ImageAlign As ContentAlignment = ContentAlignment.MiddleCenter
  Private m_TextAlign As ContentAlignment = ContentAlignment.MiddleCenter
  Private m_ImageList As ImageList
  Private m_ImageIndex As Int32 = -1

  Private keyPressed As Boolean
  Private contentRect As Rectangle

  #End Region

  #Region " IButtonControl Implementation "

  <Category("Behavior"), DefaultValue(GetType(DialogResult), "None"), _
  Description("The dialog result produced in a modal form by clicking the button.")> _
  Public Property DialogResult() As System.Windows.Forms.DialogResult Implements System.Windows.Forms.IButtonControl.DialogResult
  Get
    Return m_DialogResult
  End Get
  Set(ByVal Value As System.Windows.Forms.DialogResult)
    If [Enum].IsDefined(GetType(DialogResult), Value) Then
    m_DialogResult = Value
    End If
  End Set
  End Property

  Public Sub NotifyDefault(ByVal value As Boolean) Implements System.Windows.Forms.IButtonControl.NotifyDefault
  If m_IsDefault <> value Then
    m_IsDefault = value
  End If
  Me.Invalidate()
  End Sub

  Public Sub PerformClick() Implements System.Windows.Forms.IButtonControl.PerformClick
  If Me.CanSelect Then
    MyBase.OnClick(EventArgs.Empty)
  End If
  End Sub

  #End Region

  #Region " Properties "

  'ButtonState
  <Browsable(False)> _
  Public ReadOnly Property ButtonState() As CustomButtonState
  Get
    Return m_ButtonState
  End Get
  End Property

  'CornerRadius
  <Category("Appearance"), _
  DefaultValue(8), _
  Description("Defines the radius of the controls RoundedCorners.")> _
  Public Property CornerRadius() As Int32
  Get
    Return m_CornerRadius
  End Get
  Set(ByVal Value As Int32)
    If m_CornerRadius = Value Then Return
    m_CornerRadius = Value
    Me.Invalidate()
  End Set
  End Property

  'DefaultSize
  Protected Overrides ReadOnly Property DefaultSize() As System.Drawing.Size
  Get
    Return New Size(75, 23)
  End Get
  End Property

  'IsDefault
  <Browsable(False)> _
  Public ReadOnly Property IsDefault() As Boolean
  Get
    Return m_IsDefault
  End Get
  End Property

  'ImageList
  <Category("Appearance"), DefaultValue(GetType(ImageList), Nothing), _
  Description("The image list to get the image to display in the face of the control.")> _
  Public Property ImageList() As ImageList
  Get
    Return m_ImageList
  End Get
  Set(ByVal Value As ImageList)
    m_ImageList = Value
    Me.Invalidate()
  End Set
  End Property

  'ImageIndex
  <Category("Appearance"), DefaultValue(-1), _
  Description("The index of the image in the image list to display in the face of the control."), _
  TypeConverter(GetType(ImageIndexConverter)), _
  Editor("System.Windows.Forms.Design.ImageIndexEditor, System.Design", GetType(System.Drawing.Design.UITypeEditor))> _
  Public Property ImageIndex() As Int32
  Get
    Return m_ImageIndex
  End Get
  Set(ByVal Value As Int32)
    m_ImageIndex = Value
    Me.Invalidate()
  End Set
  End Property

  'ImageAlign
  <Category("Appearance"), DefaultValue(GetType(ContentAlignment), "MiddleCenter"), _
  Description("The alignment of the image that will be displayed in the face of the control.")> _
  Public Property ImageAlign() As ContentAlignment
  Get
    Return m_ImageAlign
  End Get
  Set(ByVal Value As ContentAlignment)
    If Not [Enum].IsDefined(GetType(ContentAlignment), Value) Then
    Throw New InvalidEnumArgumentException("value", CInt(Value), GetType(ContentAlignment))
    End If
    If m_ImageAlign = Value Then Return
    m_ImageAlign = Value
    Invalidate()
  End Set
  End Property

  'RoundCorners
  <Category("Appearance"), _
  DefaultValue(GetType(Corners), "None"), _
  Description("Gets/sets the corners of the control to round."), _
  Editor(GetType(RoundCornersEditor), GetType(UITypeEditor)), _
  DesignerSerializationVisibility(DesignerSerializationVisibility.Visible)> _
  Public Property RoundCorners() As Corners
  Get
    Return m_RoundCorners
  End Get
  Set(ByVal Value As Corners)
    If m_RoundCorners = Value Then Return
    m_RoundCorners = Value
    Me.Invalidate()
  End Set
  End Property

  'TextAlign
  <Category("Appearance"), DefaultValue(GetType(ContentAlignment), "MiddleCenter"), _
  Description("The alignment of the text that will be displayed in the face of the control.")> _
  Public Property TextAlign() As ContentAlignment
  Get
    Return m_TextAlign
  End Get
  Set(ByVal Value As ContentAlignment)
    If Not [Enum].IsDefined(GetType(ContentAlignment), Value) Then
    Throw New InvalidEnumArgumentException("value", CInt(Value), GetType(ContentAlignment))
    End If
    If m_TextAlign = Value Then Return
    m_TextAlign = Value
    Invalidate()
  End Set
  End Property

  #End Region

  #Region " Overriden Methods "

  Protected Overrides Sub OnKeyDown(ByVal kevent As System.Windows.Forms.KeyEventArgs)
  MyBase.OnKeyDown(kevent)
  If kevent.KeyValue = Keys.Space Then
    keyPressed = True
    m_ButtonState = CustomButtonState.Pressed
  End If
  OnStateChange(EventArgs.Empty)
  End Sub

  Protected Overrides Sub OnKeyUp(ByVal kevent As System.Windows.Forms.KeyEventArgs)
  MyBase.OnKeyUp(kevent)
  If kevent.KeyValue = Keys.Space Then
    If Me.ButtonState = CustomButtonState.Pressed Then
    Me.PerformClick()
    End If
    keyPressed = False
    m_ButtonState = CustomButtonState.Focused
  End If
  OnStateChange(EventArgs.Empty)
  End Sub

  Protected Overrides Sub OnMouseEnter(ByVal eventargs As System.EventArgs)
  MyBase.OnMouseEnter(eventargs)
  If Not keyPressed Then
    m_ButtonState = CustomButtonState.Hot
  End If
  OnStateChange(eventargs.Empty)
  End Sub

  Protected Overrides Sub OnMouseLeave(ByVal eventargs As System.EventArgs)
  MyBase.OnMouseLeave(eventargs)
  If Not keyPressed Then
    If Me.IsDefault Then
    m_ButtonState = CustomButtonState.Focused
    Else
    m_ButtonState = CustomButtonState.Normal
    End If
  End If
  OnStateChange(eventargs.Empty)
  End Sub

  Protected Overrides Sub OnMouseDown(ByVal mevent As System.Windows.Forms.MouseEventArgs)
  MyBase.OnMouseDown(mevent)
  If mevent.Button = MouseButtons.Left Then
    Me.Focus()
    m_ButtonState = CustomButtonState.Pressed
  End If
  OnStateChange(EventArgs.Empty)
  End Sub

  Protected Overrides Sub OnMouseUp(ByVal mevent As System.Windows.Forms.MouseEventArgs)
  MyBase.OnMouseUp(mevent)
  m_ButtonState = CustomButtonState.Focused
  OnStateChange(EventArgs.Empty)
  End Sub

  Protected Overrides Sub OnMouseMove(ByVal mevent As System.Windows.Forms.MouseEventArgs)
  MyBase.OnMouseMove(mevent)
  If New Rectangle(Point.Empty, Me.Size).Contains(mevent.X, mevent.Y) AndAlso mevent.Button = MouseButtons.Left Then
    m_ButtonState = CustomButtonState.Pressed
  Else
    If keyPressed Then Return
    m_ButtonState = CustomButtonState.Hot
  End If
  OnStateChange(EventArgs.Empty)
  End Sub

  Protected Overrides Sub OnGotFocus(ByVal e As System.EventArgs)
  MyBase.OnGotFocus(e)
  m_ButtonState = CustomButtonState.Focused
  Me.NotifyDefault(True)
  End Sub

  Protected Overrides Sub OnLostFocus(ByVal e As System.EventArgs)
  MyBase.OnLostFocus(e)
  If Me.FindForm.Focused Then
    Me.NotifyDefault(False)
  End If
  m_ButtonState = CustomButtonState.Normal
  End Sub

  Protected Overrides Sub OnEnabledChanged(ByVal e As System.EventArgs)
  MyBase.OnEnabledChanged(e)
  If Me.Enabled Then
    m_ButtonState = CustomButtonState.Normal
  Else
    m_ButtonState = CustomButtonState.Disabled
  End If
  OnStateChange(EventArgs.Empty)
  End Sub

  Protected Overrides Sub OnClick(ByVal e As System.EventArgs)
  'Click gets fired before MouseUp which is handy
  If Me.ButtonState = CustomButtonState.Pressed Then
    Me.Focus()
    Me.PerformClick()
  End If
  End Sub

  Protected Overrides Sub OnDoubleClick(ByVal e As System.EventArgs)
  If Me.ButtonState = CustomButtonState.Pressed Then
    Me.Focus()
    Me.PerformClick()
  End If
  End Sub

  Protected Overrides Function ProcessMnemonic(ByVal charCode As Char) As Boolean
  If IsMnemonic(charCode, Me.Text) Then
    MyBase.OnClick(EventArgs.Empty)
    Return True
  End If
  Return MyBase.ProcessMnemonic(charCode)
  End Function

  Protected Overrides Sub OnTextChanged(ByVal e As System.EventArgs)
  MyBase.OnTextChanged(e)
  Me.Invalidate()
  End Sub

  Protected Overrides Sub OnPaintBackground(ByVal pevent As System.Windows.Forms.PaintEventArgs)

  'Simulate Transparency
  Dim g As System.Drawing.Drawing2D.GraphicsContainer = pevent.Graphics.BeginContainer()
  Dim translateRect As Rectangle = Me.Bounds
  pevent.Graphics.TranslateTransform(-Me.Left, -Me.Top)
  Dim pe As PaintEventArgs = New PaintEventArgs(pevent.Graphics, translateRect)
  Me.InvokePaintBackground(Me.Parent, pe)
  Me.InvokePaint(Me.Parent, pe)
  pevent.Graphics.ResetTransform()
  pevent.Graphics.EndContainer(g)

  pevent.Graphics.SmoothingMode = Drawing2D.SmoothingMode.AntiAlias

  Dim shadeColor, fillColor As Color
  Dim darkColor As Color = DarkenColor(Me.BackColor, 10)
  Dim darkDarkColor As Color = DarkenColor(Me.BackColor, 25)
  Dim lightColor As Color = LightenColor(Me.BackColor, 25)
  Dim lightLightColor As Color = LightenColor(Me.BackColor, 60)

  If Me.ButtonState = CustomButtonState.Hot Then
    fillColor = lightColor
    shadeColor = darkDarkColor
  ElseIf Me.ButtonState = CustomButtonState.Pressed Then
    fillColor = Me.BackColor
    shadeColor = Me.BackColor
  Else
    fillColor = Me.BackColor
    shadeColor = darkDarkColor
  End If

  Dim r As Rectangle = Me.ClientRectangle
  Dim path As Drawing2D.GraphicsPath = RoundRectangle(r, Me.CornerRadius, Me.RoundCorners)

  Dim paintBrush As New Drawing2D.LinearGradientBrush(r, fillColor, shadeColor, Drawing2D.LinearGradientMode.Vertical)

  'We want a sharp change in the colors so define a Blend for the brush
  Dim b As New Drawing2D.Blend
  b.Positions = New Single() {0, 0.45, 0.55, 1}
  b.Factors = New Single() {0, 0, 1, 1}
  paintBrush.Blend = b

  'Draw the Button Background
  pevent.Graphics.FillPath(paintBrush, path)
  paintBrush.Dispose()

  '...and border
  Dim drawingPen As New Pen(darkDarkColor)
  pevent.Graphics.DrawPath(drawingPen, path)
  drawingPen.Dispose()

  'Get the Rectangle to be used for Content
  Dim inBounds As Boolean
  'We could use some Math to get this from the radius but I'm 
  'not great at Math so for the example this hack will suffice.
  While Not (inBounds) AndAlso r.Width >= 1 AndAlso r.Height >= 1
    inBounds = path.IsVisible(r.Left, r.Top) AndAlso _
    path.IsVisible(r.Right, r.Top) AndAlso _
    path.IsVisible(r.Left, r.Bottom) AndAlso _
    path.IsVisible(r.Right, r.Bottom)
    r.Inflate(-1, -1)

  End While

  contentRect = r

  End Sub

  Protected Overrides Sub OnPaint(ByVal e As System.Windows.Forms.PaintEventArgs)
  DrawImage(e.Graphics)
  DrawText(e.Graphics)
  DrawFocus(e.Graphics)
  MyBase.OnPaint(e)
  End Sub

  Protected Overrides Sub OnParentBackColorChanged(ByVal e As System.EventArgs)
  MyBase.OnParentBackColorChanged(e)
  Me.Invalidate()
  End Sub

  Protected Overrides Sub OnParentBackgroundImageChanged(ByVal e As System.EventArgs)
  MyBase.OnParentBackgroundImageChanged(e)
  Me.Invalidate()
  End Sub

  #End Region

  #Region " Internal Draw Methods "

  Private Sub DrawImage(ByVal g As Graphics)

  If Me.ImageList Is Nothing OrElse Me.ImageIndex = -1 Then Return
  If Me.ImageIndex < 0 OrElse Me.ImageIndex >= Me.ImageList.Images.Count Then Return

  Dim _Image As Image = Me.ImageList.Images(Me.ImageIndex)

  Dim pt As Point

  Select Case Me.ImageAlign

    Case ContentAlignment.TopLeft
    pt.X = contentRect.Left
    pt.Y = contentRect.Top

    Case ContentAlignment.TopCenter
    pt.X = (Width - _Image.Width) \ 2
    pt.Y = contentRect.Top

    Case ContentAlignment.TopRight
    pt.X = contentRect.Right - _Image.Width
    pt.Y = contentRect.Top

    Case ContentAlignment.MiddleLeft
    pt.X = contentRect.Left
    pt.Y = (Height - _Image.Height) \ 2

    Case ContentAlignment.MiddleCenter
    pt.X = (Width - _Image.Width) \ 2
    pt.Y = (Height - _Image.Height) \ 2

    Case ContentAlignment.MiddleRight
    pt.X = contentRect.Right - _Image.Width
    pt.Y = (Height - _Image.Height) \ 2

    Case ContentAlignment.BottomLeft
    pt.X = contentRect.Left
    pt.Y = contentRect.Bottom - _Image.Height

    Case ContentAlignment.BottomCenter
    pt.X = (Width - _Image.Width) \ 2
    pt.Y = contentRect.Bottom - _Image.Height

    Case ContentAlignment.BottomRight
    pt.X = contentRect.Right - _Image.Width
    pt.Y = contentRect.Bottom - _Image.Height

  End Select

  If Me.ButtonState = CustomButtonState.Pressed Then
    pt.Offset(1, 1)
  End If

  If Me.Enabled Then
    Me.ImageList.Draw(g, pt, Me.ImageIndex)
  Else
    ControlPaint.DrawImageDisabled(g, _Image, pt.X, pt.Y, Me.BackColor)
  End If

  End Sub

  Private Sub DrawText(ByVal g As Graphics)

  Dim TextBrush As New SolidBrush(Me.ForeColor)

  Dim R As RectangleF = RectangleF.op_Implicit(contentRect)

  If Not Me.Enabled Then TextBrush.Color = SystemColors.GrayText

  Dim sf As New StringFormat(StringFormatFlags.NoWrap Or StringFormatFlags.NoClip)

  If ShowKeyboardCues Then
    sf.HotkeyPrefix = System.Drawing.Text.HotkeyPrefix.Show
  Else
    sf.HotkeyPrefix = System.Drawing.Text.HotkeyPrefix.Hide
  End If

  Select Case Me.TextAlign
    Case ContentAlignment.TopLeft
    sf.Alignment = StringAlignment.Near
    sf.LineAlignment = StringAlignment.Near

    Case ContentAlignment.TopCenter
    sf.Alignment = StringAlignment.Center
    sf.LineAlignment = StringAlignment.Near

    Case ContentAlignment.TopRight
    sf.Alignment = StringAlignment.Far
    sf.LineAlignment = StringAlignment.Near

    Case ContentAlignment.MiddleLeft
    sf.Alignment = StringAlignment.Near
    sf.LineAlignment = StringAlignment.Center

    Case ContentAlignment.MiddleCenter
    sf.Alignment = StringAlignment.Center
    sf.LineAlignment = StringAlignment.Center

    Case ContentAlignment.MiddleRight
    sf.Alignment = StringAlignment.Far
    sf.LineAlignment = StringAlignment.Center

    Case ContentAlignment.BottomLeft
    sf.Alignment = StringAlignment.Near
    sf.LineAlignment = StringAlignment.Far

    Case ContentAlignment.BottomCenter
    sf.Alignment = StringAlignment.Center
    sf.LineAlignment = StringAlignment.Far

    Case ContentAlignment.BottomRight
    sf.Alignment = StringAlignment.Far
    sf.LineAlignment = StringAlignment.Far

  End Select

  If Me.ButtonState = CustomButtonState.Pressed Then
    R.Offset(1, 1)
  End If

  If Me.Enabled Then
    g.DrawString(Me.Text, Me.Font, TextBrush, R, sf)
  Else
    ControlPaint.DrawStringDisabled(g, Me.Text, Me.Font, Me.BackColor, R, sf)
  End If

  End Sub

  Private Sub DrawFocus(ByVal g As Graphics)
  Dim r As Rectangle = contentRect
  r.Inflate(1, 1)
  If Me.Focused AndAlso Me.ShowFocusCues AndAlso Me.TabStop Then
    ControlPaint.DrawFocusRectangle(g, r, Me.ForeColor, Me.BackColor)
  End If

  End Sub

  #End Region

  #Region " Helper Methods "

  Private Function RoundRectangle(ByVal r As Rectangle, ByVal radius As Int32, ByVal corners As Corners) As System.Drawing.Drawing2D.GraphicsPath

  'Make sure the Path fits inside the rectangle
  r.Width -= 1
  r.Height -= 1

  'Scale the radius if it's too large to fit.
  If (radius > (r.Width)) Then radius = r.Width
  If (radius > (r.Height)) Then radius = r.Height

  Dim path As New System.Drawing.Drawing2D.GraphicsPath

  If radius <= 0 Then
    path.AddRectangle(r)
  Else
    If (corners And corners.TopLeft) = corners.TopLeft Then
    path.AddArc(r.Left, r.Top, radius, radius, 180, 90)
    Else
    path.AddLine(r.Left, r.Top, r.Left, r.Top)
    End If

    If (corners And corners.TopRight) = corners.TopRight Then
    path.AddArc(r.Right - radius, r.Top, radius, radius, 270, 90)
    Else
    path.AddLine(r.Right, r.Top, r.Right, r.Top)
    End If


    If (corners And corners.BottomRight) = corners.BottomRight Then
    path.AddArc(r.Right - radius, r.Bottom - radius, radius, radius, 0, 90)
    Else
    path.AddLine(r.Right, r.Bottom, r.Right, r.Bottom)
    End If

    If (corners And corners.BottomLeft) = corners.BottomLeft Then
    path.AddArc(r.Left, r.Bottom - radius, radius, radius, 90, 90)
    Else
    path.AddLine(r.Left, r.Bottom, r.Left, r.Bottom)
    End If

    path.CloseFigure()

  End If

  Return path

  End Function

  'The ControlPaint Class has methods to Lighten and Darken Colors, but they return a Solid Color.
  'The Following 2 methods return a modified color with original Alpha.
  Private Function DarkenColor(ByVal colorIn As Color, ByVal percent As Int32) As Color
  'This method returns Black if you Darken by 100%

  If percent < 0 OrElse percent > 100 Then
    Throw New ArgumentOutOfRangeException("percent")
  End If

  Dim a, r, g, b As Int32

  a = colorIn.A
  r = colorIn.R - CInt((colorIn.R / 100) * percent)
  g = colorIn.G - CInt((colorIn.G / 100) * percent)
  b = colorIn.B - CInt((colorIn.B / 100) * percent)

  Return Color.FromArgb(a, r, g, b)

  End Function

  Private Function LightenColor(ByVal colorIn As Color, ByVal percent As Int32) As Color

  'This method returns White if you lighten by 100%
  If percent < 0 OrElse percent > 100 Then
    Throw New ArgumentOutOfRangeException("percent")
  End If

  Dim a, r, g, b As Int32

  a = colorIn.A
  r = colorIn.R + CInt(((255 - colorIn.R) / 100) * percent)
  g = colorIn.G + CInt(((255 - colorIn.G) / 100) * percent)
  b = colorIn.B + CInt(((255 - colorIn.B) / 100) * percent)

  Return Color.FromArgb(a, r, g, b)
  End Function

  #End Region

  Private Sub OnStateChange(ByVal e As EventArgs)
  Static currentState As CustomButtonState
  'Repaint the button only if the state has actually changed
  If Me.ButtonState = currentState Then Return
  currentState = Me.ButtonState
  Me.Invalidate()
  End Sub

  End Class

  #Region " Custom TypeEditor for RoundCorners property "

  <PermissionSetAttribute(SecurityAction.LinkDemand, Unrestricted:=True), PermissionSetAttribute(SecurityAction.InheritanceDemand, Unrestricted:=True)> _
  Public Class RoundCornersEditor
  Inherits UITypeEditor

  Public Overloads Overrides Function GetEditStyle(ByVal context As System.ComponentModel.ITypeDescriptorContext) As System.Drawing.Design.UITypeEditorEditStyle
  Return UITypeEditorEditStyle.DropDown
  End Function

  Public Overloads Overrides Function EditValue(ByVal context As System.ComponentModel.ITypeDescriptorContext, ByVal provider As System.IServiceProvider, ByVal value As Object) As Object

  If Not TypeOf value Is Corners OrElse _
    provider Is Nothing Then
    Return value
  End If

  Dim edSvc As IWindowsFormsEditorService = CType(provider.GetService(GetType(IWindowsFormsEditorService)), IWindowsFormsEditorService)
  If Not (edSvc Is Nothing) Then
    Dim lb As New CheckedListBox
    lb.BorderStyle = System.Windows.Forms.BorderStyle.None
    lb.CheckOnClick = True

    lb.Items.Add("TopLeft", (DirectCast(context.Instance, CustomButton).RoundCorners And Corners.TopLeft) = Corners.TopLeft)
    lb.Items.Add("TopRight", (DirectCast(context.Instance, CustomButton).RoundCorners And Corners.TopRight) = Corners.TopRight)
    lb.Items.Add("BottomLeft", (DirectCast(context.Instance, CustomButton).RoundCorners And Corners.BottomLeft) = Corners.BottomLeft)
    lb.Items.Add("BottomRight", (DirectCast(context.Instance, CustomButton).RoundCorners And Corners.BottomRight) = Corners.BottomRight)

    edSvc.DropDownControl(lb)
    Dim cornerFlags As Corners
    For Each o As Object In lb.CheckedItems
    cornerFlags = cornerFlags Or DirectCast([Enum].Parse(GetType(Corners), o.ToString), Corners)
    Next
    lb.Dispose()
    edSvc.CloseDropDown()
    Return cornerFlags
  End If

  Return value

  End Function

  End Class

  #End Region

  End Namespace
    

---

CSharp Sample:

using System;
  using System.ComponentModel;
  using System.Drawing;
  using System.Drawing.Design;
  using System.Windows.Forms;
  using System.Windows.Forms.Design;
  using System.Security.Permissions;

  namespace Dotnetrix.Samples.CSharp
  {
    [System.Flags]
    public enum Corners
    {
    None = 0,
    TopLeft = 1,
    TopRight = 2,
    BottomLeft = 4,
    BottomRight = 8,
    All = TopLeft | TopRight | BottomLeft | BottomRight
    }


    public enum CustomButtonState
    {
    Normal = 1,
    Hot,
    Pressed,
    Disabled,
    Focused
    }


    public class CustomButton : Control, IButtonControl
    {
    public CustomButton():base()
    {
      this.SetStyle(ControlStyles.Selectable | ControlStyles.StandardClick | ControlStyles.ResizeRedraw | ControlStyles.AllPaintingInWmPaint | ControlStyles.DoubleBuffer | ControlStyles.UserPaint | ControlStyles.SupportsTransparentBackColor, true);
    }


  #region Private Instance Variables

    private DialogResult m_DialogResult;
    private bool m_IsDefault;
    
    private int m_CornerRadius  = 8;
    private Corners m_RoundCorners;
    private CustomButtonState m_ButtonState = CustomButtonState.Normal;
    
    private ContentAlignment m_ImageAlign = ContentAlignment.MiddleCenter;
    private ContentAlignment m_TextAlign = ContentAlignment.MiddleCenter;
    private ImageList m_ImageList;
    private int m_ImageIndex = -1;
    
    private bool keyPressed;
    private Rectangle contentRect;

  #endregion

  #region IButtonControl Implementation

    [Category("Behavior"), DefaultValue(typeof(DialogResult), "None")]
    [Description("The dialog result produced in a modal form by clicking the button.")]
    public DialogResult DialogResult
    {
      get{return m_DialogResult;}
      set
      {
        if (Enum.IsDefined(typeof(DialogResult), value))
        m_DialogResult = value;
      }
    }
    

    public void NotifyDefault(bool value)
    {
      if (m_IsDefault != value)
        m_IsDefault = value;
      this.Invalidate();
    }


    public void PerformClick()
    {
      if (this.CanSelect)
        base.OnClick(EventArgs.Empty);
    }


  #endregion

  #region Properties

    //ButtonState
    [Browsable(false)]
    public CustomButtonState ButtonState
    {
      get{return m_ButtonState;}
    }


    //CornerRadius
    [Category("Appearance")]
    [DefaultValue(8)]
    [Description("Defines the radius of the controls RoundedCorners.")]
    public int CornerRadius
    {
      get{return m_CornerRadius;}
      set
      {
        if (m_CornerRadius == value) 
        return;
        m_CornerRadius = value;
        this.Invalidate();
      }
    }


    //DefaultSize
    protected override System.Drawing.Size DefaultSize
    {
      get{return new Size(75, 23);}
    }


    //IsDefault
    [Browsable(false)]
    public bool IsDefault
    {
      get{return m_IsDefault;}
    }


    //ImageList
    [Category("Appearance"), DefaultValue(typeof(ImageList), null)]
    [Description("The image list to get the image to display in the face of the control.")]
    public ImageList ImageList
    {
      get{return m_ImageList;}
      set
      {
        m_ImageList = value;
        this.Invalidate();
      }
    }


    //ImageIndex
    [Category("Appearance"), DefaultValue(-1)]
    [Description("The index of the image in the image list to display in the face of the control.")]
    [TypeConverter(typeof(ImageIndexConverter))]
    [Editor("System.Windows.Forms.Design.ImageIndexEditor, System.Design", typeof(System.Drawing.Design.UITypeEditor))]
    public int ImageIndex
    {
      get{return m_ImageIndex;}
      set
      {
        m_ImageIndex = value;
        this.Invalidate();
      }
    }


    //ImageAlign
    [Category("Appearance"), DefaultValue(typeof(ContentAlignment), "MiddleCenter")]
    [Description("The alignment of the image that will be displayed in the face of the control.")]
    public ContentAlignment ImageAlign
    {
      get{return m_ImageAlign;}
      set
      {
        if (!Enum.IsDefined(typeof(ContentAlignment), value))
        throw new InvalidEnumArgumentException("value", (int)value, typeof(ContentAlignment));
        if (m_ImageAlign == value )
        return;
        m_ImageAlign = value;
        this.Invalidate();
      }
    }


    //RoundCorners
    [Category("Appearance")]
    [DefaultValue(typeof(Corners), "None")]
    [Description("Gets/sets the corners of the control to round.")]
    [Editor(typeof(RoundCornersEditor), typeof(UITypeEditor))]
    [DesignerSerializationVisibility(DesignerSerializationVisibility.Visible)]
    public Corners RoundCorners
    {
      get{return m_RoundCorners;}
      set
      {
        if (m_RoundCorners == value)
        return;
        m_RoundCorners = value;
        this.Invalidate();
      }
    }


    //TextAlign
    [Category("Appearance"), DefaultValue(typeof(ContentAlignment), "MiddleCenter")]
    [Description("The alignment of the text that will be displayed in the face of the control.")]
    public ContentAlignment TextAlign
    {
      get{return m_TextAlign;}
      set
      {
        if (!Enum.IsDefined(typeof(ContentAlignment), value))
        throw new InvalidEnumArgumentException("value", (int)value, typeof(ContentAlignment));
        if (m_TextAlign == value)
        return;
        m_TextAlign = value;
        this.Invalidate();
      }
    }


  #endregion

  #region Overriden Methods

    protected override void OnKeyDown(KeyEventArgs e)
    {
      base.OnKeyDown (e);
      if (e.KeyCode == Keys.Space)
      {
        keyPressed = true;
        m_ButtonState = CustomButtonState.Pressed;
      }
      OnStateChange(EventArgs.Empty);
    }


    protected override void OnKeyUp(KeyEventArgs e)
    {
      base.OnKeyUp (e);
      if (e.KeyCode == Keys.Space)
      {
        if (this.ButtonState == CustomButtonState.Pressed)
        this.PerformClick();
        keyPressed = false;
        m_ButtonState = CustomButtonState.Focused;
      }
      OnStateChange(EventArgs.Empty);
    }


    protected override void OnMouseEnter(EventArgs e)
    {
      base.OnMouseEnter (e);
      if (!keyPressed)
        m_ButtonState = CustomButtonState.Hot;
      OnStateChange(EventArgs.Empty);
    }


    protected override void OnMouseLeave(EventArgs e)
    {
      base.OnMouseLeave (e);
      if (!keyPressed)
        if (this.IsDefault)
        m_ButtonState = CustomButtonState.Focused;
        else
        m_ButtonState = CustomButtonState.Normal;
      OnStateChange(EventArgs.Empty);
    }


    protected override void OnMouseDown(MouseEventArgs e)
    {
      base.OnMouseDown (e);
      if (e.Button == MouseButtons.Left)
      {
        this.Focus();
        m_ButtonState = CustomButtonState.Pressed;
      }
      OnStateChange(EventArgs.Empty);
    }


    protected override void OnMouseUp(MouseEventArgs e)
    {
      base.OnMouseUp (e);
      m_ButtonState = CustomButtonState.Focused;
      OnStateChange(EventArgs.Empty);
    }


    protected override void OnMouseMove(MouseEventArgs e)
    {
      base.OnMouseMove (e);
      if (new Rectangle(Point.Empty, this.Size).Contains(e.X, e.Y) && e.Button == MouseButtons.Left)
        m_ButtonState = CustomButtonState.Pressed;
      else
      {
        if(keyPressed)
        return;
        m_ButtonState = CustomButtonState.Hot;
      }
      OnStateChange(EventArgs.Empty);
    }


    protected override void OnGotFocus(EventArgs e)
    {
      base.OnGotFocus (e);
      m_ButtonState = CustomButtonState.Focused;
      this.NotifyDefault(true);
    }


    protected override void OnLostFocus(EventArgs e)
    {
      base.OnLostFocus (e);
      if (this.FindForm().Focused)
        this.NotifyDefault(false);
      m_ButtonState = CustomButtonState.Normal;
    }


    protected override void OnEnabledChanged(EventArgs e)
    {
      base.OnEnabledChanged (e);
      if (this.Enabled)
        m_ButtonState = CustomButtonState.Normal;
      else
        m_ButtonState = CustomButtonState.Disabled;
      OnStateChange(EventArgs.Empty);
    }


    protected override void OnClick(EventArgs e)
    {
      //Click gets fired before MouseUp which is handy
      if (this.ButtonState == CustomButtonState.Pressed)
      {
        this.Focus();
        this.PerformClick();
      }
    }


    protected override void OnDoubleClick(EventArgs e)
    {
      if (this.ButtonState == CustomButtonState.Pressed)
      {
        this.Focus();
        this.PerformClick();
      }
    }


    protected override bool ProcessMnemonic(char charCode)
    {
      if (IsMnemonic(charCode, this.Text))
      {
        base.OnClick(EventArgs.Empty);
        return true;
      }
      return base.ProcessMnemonic(charCode);
    }


    protected override void OnTextChanged(EventArgs e)
    {
      base.OnTextChanged(e);
      this.Invalidate();
    }


    protected override void OnPaintBackground(PaintEventArgs pevent)
    {
      //Simulate Transparency
      System.Drawing.Drawing2D.GraphicsContainer g = pevent.Graphics.BeginContainer();
      Rectangle translateRect = this.Bounds;
      pevent.Graphics.TranslateTransform(-this.Left, -this.Top);
      PaintEventArgs pe = new PaintEventArgs(pevent.Graphics, translateRect);
      this.InvokePaintBackground(this.Parent, pe);
      this.InvokePaint(this.Parent, pe);
      pevent.Graphics.ResetTransform();
      pevent.Graphics.EndContainer(g);

      pevent.Graphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;

      Color shadeColor, fillColor; 
      Color darkColor = DarkenColor(this.BackColor, 10);
      Color darkDarkColor = DarkenColor(this.BackColor, 25);
      Color lightColor = LightenColor(this.BackColor, 25);
      Color lightLightColor = LightenColor(this.BackColor, 60);

      if (this.ButtonState == CustomButtonState.Hot)
      {
        fillColor = lightColor;
        shadeColor = darkDarkColor;
      }
      else if (this.ButtonState == CustomButtonState.Pressed)
      {
        fillColor = this.BackColor;
        shadeColor = this.BackColor;
      }
      else
      {
        fillColor = this.BackColor;
        shadeColor = darkDarkColor;
      }

      Rectangle r = this.ClientRectangle;
      System.Drawing.Drawing2D.GraphicsPath path = RoundRectangle(r, this.CornerRadius, this.RoundCorners);

      System.Drawing.Drawing2D.LinearGradientBrush paintBrush = new System.Drawing.Drawing2D.LinearGradientBrush(r, fillColor, shadeColor, System.Drawing.Drawing2D.LinearGradientMode.Vertical);

      //We want a sharp change in the colors so define a Blend for the brush
      System.Drawing.Drawing2D.Blend b = new System.Drawing.Drawing2D.Blend();
      b.Positions = new float[] {0, 0.45F, 0.55F, 1};
      b.Factors = new float[] {0, 0, 1, 1};
      paintBrush.Blend = b;

      //Draw the Button Background
      pevent.Graphics.FillPath(paintBrush, path);
      paintBrush.Dispose();

      //...and border
      Pen drawingPen = new Pen(darkDarkColor);
      pevent.Graphics.DrawPath(drawingPen, path);
      drawingPen.Dispose();

      //Get the Rectangle to be used for Content
      bool inBounds = false;
      //We could use some Math to get this from the radius but I'm 
      //not great at Math so for the example this hack will suffice.
      while (!inBounds && r.Width >= 1 && r.Height >= 1)
      {
        inBounds = path.IsVisible(r.Left, r.Top) &&
            path.IsVisible(r.Right, r.Top) &&
            path.IsVisible(r.Left, r.Bottom) &&
            path.IsVisible(r.Right, r.Bottom);
        r.Inflate(-1, -1);
        
      }

      contentRect = r;

    }


    protected override void OnPaint(PaintEventArgs e)
    {
      DrawImage(e.Graphics);
      DrawText(e.Graphics);
      DrawFocus(e.Graphics);
      base.OnPaint (e);
    }


    protected override void OnParentBackColorChanged(EventArgs e)
    {
      base.OnParentBackColorChanged (e);
      this.Invalidate();
    }


    protected override void OnParentBackgroundImageChanged(EventArgs e)
    {
      base.OnParentBackgroundImageChanged (e);
      this.Invalidate();
    }


  #endregion

  #region Internal Draw Methods

    private void DrawImage(Graphics g)
    {
      if (this.ImageList == null || this.ImageIndex == -1)
        return;
      if (this.ImageIndex < 0 || this.ImageIndex >= this.ImageList.Images.Count)
        return;

      Image _Image = this.ImageList.Images[this.ImageIndex];

      Point pt = Point.Empty;

      switch (this.ImageAlign)
      {
        case ContentAlignment.TopLeft:
        pt.X = contentRect.Left;
        pt.Y = contentRect.Top;
        break;

        case ContentAlignment.TopCenter:
        pt.X = (Width - _Image.Width) / 2;
        pt.Y = contentRect.Top;
        break;

        case ContentAlignment.TopRight:
        pt.X = contentRect.Right - _Image.Width;
        pt.Y = contentRect.Top;
        break;

        case ContentAlignment.MiddleLeft:
        pt.X = contentRect.Left;
        pt.Y = (Height - _Image.Height) / 2;
        break;

        case ContentAlignment.MiddleCenter:
        pt.X = (Width - _Image.Width) / 2;
        pt.Y = (Height - _Image.Height) / 2;
        break;

        case ContentAlignment.MiddleRight:
        pt.X = contentRect.Right - _Image.Width;
        pt.Y = (Height - _Image.Height) / 2;
        break;

        case ContentAlignment.BottomLeft:
        pt.X = contentRect.Left;
        pt.Y = contentRect.Bottom - _Image.Height;
        break;

        case ContentAlignment.BottomCenter:
        pt.X = (Width - _Image.Width) / 2;
        pt.Y = contentRect.Bottom - _Image.Height;
        break;

        case ContentAlignment.BottomRight:
        pt.X = contentRect.Right - _Image.Width;
        pt.Y = contentRect.Bottom - _Image.Height;
        break;
      }

      if (this.ButtonState == CustomButtonState.Pressed)
        pt.Offset(1, 1);

      if (this.Enabled)
        this.ImageList.Draw(g, pt, this.ImageIndex);
      else
        ControlPaint.DrawImageDisabled(g, _Image, pt.X, pt.Y, this.BackColor);

    }


    private void DrawText(Graphics g)
    {
      SolidBrush TextBrush = new SolidBrush(this.ForeColor);
      
      RectangleF R = (RectangleF)contentRect;
      
      if (!this.Enabled)
        TextBrush.Color = SystemColors.GrayText;
      
      StringFormat sf = new StringFormat(StringFormatFlags.NoWrap | StringFormatFlags.NoClip);
      
      if (ShowKeyboardCues)
        sf.HotkeyPrefix = System.Drawing.Text.HotkeyPrefix.Show;
      else
        sf.HotkeyPrefix = System.Drawing.Text.HotkeyPrefix.Hide;
      
      switch (this.TextAlign)
      {
        case ContentAlignment.TopLeft:
        sf.Alignment = StringAlignment.Near;
        sf.LineAlignment = StringAlignment.Near;
        break;

        case ContentAlignment.TopCenter:
        sf.Alignment = StringAlignment.Center;
        sf.LineAlignment = StringAlignment.Near;
        break;

        case ContentAlignment.TopRight:
        sf.Alignment = StringAlignment.Far;
        sf.LineAlignment = StringAlignment.Near;
        break;
        
        case ContentAlignment.MiddleLeft:
        sf.Alignment = StringAlignment.Near;
        sf.LineAlignment = StringAlignment.Center;
        break;

        case ContentAlignment.MiddleCenter:
        sf.Alignment = StringAlignment.Center;
        sf.LineAlignment = StringAlignment.Center;
        break;

        case ContentAlignment.MiddleRight:
        sf.Alignment = StringAlignment.Far;
        sf.LineAlignment = StringAlignment.Center;
        break;

        case ContentAlignment.BottomLeft:
        sf.Alignment = StringAlignment.Near;
        sf.LineAlignment = StringAlignment.Far;
        break;

        case ContentAlignment.BottomCenter:
        sf.Alignment = StringAlignment.Center;
        sf.LineAlignment = StringAlignment.Far;
        break;

        case ContentAlignment.BottomRight:
        sf.Alignment = StringAlignment.Far;
        sf.LineAlignment = StringAlignment.Far;
        break;
      }

      if (this.ButtonState == CustomButtonState.Pressed)
        R.Offset(1, 1);

      if (this.Enabled)
        g.DrawString(this.Text, this.Font, TextBrush, R, sf);
      else
        ControlPaint.DrawStringDisabled(g, this.Text, this.Font, this.BackColor, R, sf);
      
    }


    private void DrawFocus(Graphics g)
    {
      Rectangle r = contentRect;
      r.Inflate(1, 1);
      if (this.Focused && this.ShowFocusCues && this.TabStop)
        ControlPaint.DrawFocusRectangle(g, r, this.ForeColor, this.BackColor);
    }

    
  #endregion

  #region Helper Methods

    private System.Drawing.Drawing2D.GraphicsPath RoundRectangle(Rectangle r, int radius, Corners corners)
    {
      //Make sure the Path fits inside the rectangle
      r.Width -= 1;
      r.Height -= 1;
      
      //Scale the radius if it's too large to fit.
      if (radius > (r.Width))
        radius = r.Width;
      if (radius > (r.Height))
        radius = r.Height;
      
      System.Drawing.Drawing2D.GraphicsPath path = new System.Drawing.Drawing2D.GraphicsPath();
      
      if (radius <= 0 )
        path.AddRectangle(r);
      else
        if ((corners & Corners.TopLeft) == Corners.TopLeft)
        path.AddArc(r.Left, r.Top, radius, radius, 180, 90);
      else
        path.AddLine(r.Left, r.Top, r.Left, r.Top);
      
      if ((corners & Corners.TopRight) == Corners.TopRight)
        path.AddArc(r.Right - radius, r.Top, radius, radius, 270, 90);
      else
        path.AddLine(r.Right, r.Top, r.Right, r.Top);
      
      if ((corners & Corners.BottomRight) == Corners.BottomRight)
        path.AddArc(r.Right - radius, r.Bottom - radius, radius, radius, 0, 90);
      else
        path.AddLine(r.Right, r.Bottom, r.Right, r.Bottom);
      
      if ((corners & Corners.BottomLeft) == Corners.BottomLeft)
        path.AddArc(r.Left, r.Bottom - radius, radius, radius, 90, 90);
      else
        path.AddLine(r.Left, r.Bottom, r.Left, r.Bottom);
      
      path.CloseFigure();

      return path;
    }


    //The ControlPaint Class has methods to Lighten and Darken Colors, but they return a Solid Color.
    //The Following 2 methods return a modified color with original Alpha.
    private Color DarkenColor(Color colorIn, int percent)
    {
      //This method returns Black if you Darken by 100%
      
      if (percent < 0 || percent > 100)
        throw new ArgumentOutOfRangeException("percent");
      
      int a, r, g, b;
      
      a = colorIn.A;
      r = colorIn.R - (int)((colorIn.R / 100f) * percent);
      g = colorIn.G - (int)((colorIn.G / 100f) * percent);
      b = colorIn.B - (int)((colorIn.B / 100f) * percent);
      
      return Color.FromArgb(a, r, g, b);
    }
    

    private Color LightenColor(Color colorIn, int percent)
    {
      //This method returns White if you lighten by 100%
      
      if (percent < 0 || percent > 100)
        throw new ArgumentOutOfRangeException("percent");
      
      int a, r, g, b;
      
      a = colorIn.A;
      r = colorIn.R + (int)(((255f - colorIn.R) / 100f) * percent);
      g = colorIn.G + (int)(((255f - colorIn.G) / 100f) * percent);
      b = colorIn.B + (int)(((255f - colorIn.B) / 100f) * percent);
      
      return Color.FromArgb(a, r, g, b);
    }


  #endregion

    private CustomButtonState currentState; 
    private void OnStateChange(EventArgs e)
    {
      //Repaint the button only if the state has actually changed
      if (this.ButtonState == currentState)
        return;
      currentState = this.ButtonState;
      this.Invalidate();
    }


    }

  #region Custom TypeEditor for RoundCorners property

    [PermissionSetAttribute(SecurityAction.LinkDemand, Unrestricted=true)]
    [PermissionSetAttribute(SecurityAction.InheritanceDemand, Unrestricted=true)]
    public class RoundCornersEditor : UITypeEditor
    {
    public override UITypeEditorEditStyle GetEditStyle(ITypeDescriptorContext context)
    {
      return UITypeEditorEditStyle.DropDown;
    }
    
    public override Object EditValue(ITypeDescriptorContext context, IServiceProvider provider, Object value)
    {
      if (value != typeof(Corners) ||  provider == null)
        return value;
      
      IWindowsFormsEditorService edSvc = (IWindowsFormsEditorService)provider.GetService(typeof(IWindowsFormsEditorService));
      if (edSvc != null)
      {
        CheckedListBox lb = new CheckedListBox();
        lb.BorderStyle = BorderStyle.None;
        lb.CheckOnClick = true;
        
        lb.Items.Add("TopLeft", (((CustomButton)context.Instance).RoundCorners & Corners.TopLeft) == Corners.TopLeft);
        lb.Items.Add("TopRight", (((CustomButton)context.Instance).RoundCorners & Corners.TopRight) == Corners.TopRight);
        lb.Items.Add("BottomLeft", (((CustomButton)context.Instance).RoundCorners & Corners.BottomLeft) == Corners.BottomLeft);
        lb.Items.Add("BottomRight", (((CustomButton)context.Instance).RoundCorners & Corners.BottomRight) == Corners.BottomRight);

        edSvc.DropDownControl(lb);
        Corners cornerFlags = Corners.None;
        foreach (object o in lb.CheckedItems)
        {
        cornerFlags = cornerFlags | (Corners)Enum.Parse(typeof(Corners), o.ToString());
        }
        lb.Dispose();
        edSvc.CloseDropDown();
        return cornerFlags;
      }
      return value;
    }
    
    }

  #endregion

  }
       

by: Mick Dohertys'