¿Cambiar el color de un pequeño círculo (punto) contenido en el botón de opción para que sea rojo?

Question

¿Cómo puedo cambiar el color de un círculo pequeño (punto) contenido en el botón de opción para que sea rojo en la aplicación Winform? ¿Utiliza VB.NET o C#?

Regard & Gracias, Dewi

==================================== ======================
Voy a compartir, puede ser útil para otros. Este programa funciona

Imports System.Drawing.Drawing2D 

Public Class Form1 

Public Class MyRadioButton 
    Inherits RadioButton 

    Private m_OnColor As Color 
    Private m_OffColor As Color 

    Public Sub New(ByVal On_Color As Color, ByVal Off_Color As Color) 
     m_OnColor = On_Color 
     m_OffColor = Off_Color 
     SetStyle(ControlStyles.SupportsTransparentBackColor, True) 
     BackColor = Color.Transparent 
    End Sub 

    Public Property OnColor() As Color 
     Get 
      Return m_OnColor 
     End Get 
     Set(ByVal value As Color) 
      m_OnColor = value 
     End Set 
    End Property 

    Public Property OffColor() As Color 
     Get 
      Return m_OffColor 
     End Get 
     Set(ByVal value As Color) 
      m_OffColor = value 
     End Set 
    End Property 

    Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs) 
     MyBase.OnPaint(e) 

     Dim g As Graphics = e.Graphics 
     g.SmoothingMode = SmoothingMode.AntiAlias 

     Dim dotDiameter As Integer = ClientRectangle.Height - 17 
     Dim innerRect As New RectangleF(1.8F, 7.8F, dotDiameter, dotDiameter) 

     If Me.Checked Then 
      g.FillEllipse(New SolidBrush(OnColor), innerRect) 
     Else 
      g.FillEllipse(New SolidBrush(OffColor), innerRect) 
     End If 

     g.DrawString(Text, Font, New SolidBrush(ForeColor), dotDiameter + 17, 1) 
    End Sub 

End Class 


Dim objRadio As New MyRadioButton(Color.Blue, Color.Red) 

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load 
    objRadio.Location = New Point(100, 100) 
    objRadio.Visible = True 
    Me.Controls.Add(objRadio) 
End Sub 

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click 
    If objRadio.Checked Then 
     objRadio.Checked = False 
    Else 
     objRadio.Checked = True 
    End If 
End Sub 


End Class 

Answer 1

Here's un ejemplo de un cuadro de lista winforms propietario dibujado simulando una lista de botones de radio que se puede utilizar para lo que quieres.

Edit:Here es un ejemplo más detallado de control personalizado de Winforms.

Answer 2

Tomé el código VB del OP como base y con un poco de ayuda de MSDN sobre el uso del PathGradientBrush surgió esta clase derivada para C#. Los botones verde y rojo que se ven en la imagen a continuación usan mi código, los dos azules son la versión normal.

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 
using System.Windows.Forms; 
using System.Drawing; 
using System.Drawing.Drawing2D; 

namespace WindowsFormsApplication1 
{ 
    public class ColouredRadioButton : RadioButton 
    { 
     // Fields 
     private Color m_OnColour; 
     private Color m_OffColour; 
     private Rectangle m_glint; 
     private Rectangle m_circle; 
     private PathGradientBrush m_flareBrush; 
     private Pen m_outline; 

     // Properties 
     public Color OnColour 
     { 
      get 
      { 
       return m_OnColour; 
      } 
      set 
      { 
       if ((value == Color.White) || (value == Color.Transparent)) 
        m_OnColour = Color.Empty; 
       else 
        m_OnColour = value; 
      } 
     } 
     public Color OffColour 
     { 
      get 
      { 
       return m_OffColour; 
      } 
      set 
      { 
       if ((value == Color.White) || (value == Color.Transparent)) 
        m_OffColour = Color.Empty; 
       else 
        m_OffColour = value; 
      } 
     } 

     // Constructor 
     public ColouredRadioButton() 
     { 
      // Init 
      m_circle = new Rectangle(2, 5, 7, 7 /*Magic Numbers*/); 
      m_glint = new Rectangle(3, 6, 4, 4 /*Magic Numbers*/); 
      m_outline = new Pen(new SolidBrush(Color.Black), 1F /*Magic Numbers*/); 

      // Generate Glint 
      GraphicsPath Path = new GraphicsPath(); 
      Path.AddEllipse(m_glint); 
      m_flareBrush = new PathGradientBrush(Path); 
      m_flareBrush.CenterColor = Color.White; 
      m_flareBrush.SurroundColors = new Color[] { Color.Transparent }; 
      m_flareBrush.FocusScales = new PointF(0.5F, 0.5F/*Magic Numbers*/); 

      // Allows for Overlaying 
      SetStyle(ControlStyles.SupportsTransparentBackColor, true); 
      BackColor = Color.Transparent; 
     } 

     // Methods 
     protected override void OnPaint(PaintEventArgs e) 
     { 
      // Init 
      base.OnPaint(e); 
      Graphics g = e.Graphics; 
      g.SmoothingMode = SmoothingMode.AntiAlias; 

      // Overlay Graphic 
      if (this.Checked) 
      { 
       if (OnColour != Color.Empty) 
       { 
        g.FillEllipse(new SolidBrush(OnColour), m_circle); 
        g.FillEllipse(m_flareBrush, m_glint); 
        g.DrawEllipse(m_outline, m_circle); 
       } 
      } 
      else 
      { 
       if (OffColour != Color.Empty) 
       { 
        g.FillEllipse(new SolidBrush(OffColour), m_circle); 
        g.FillEllipse(m_flareBrush, m_glint); 
        g.DrawEllipse(m_outline, m_circle); 
       } 
      } 
     } 
    } 
} 

Si tienes curiosidad y quieres el código de la bola roja grande que lo estaba usando para poner a prueba las características de pincel, aquí va ...

using System; 
using System.Collections.Generic; 
using System.ComponentModel; 
using System.Data; 
using System.Drawing; 
using System.Linq; 
using System.Text; 
using System.Windows.Forms; 
using System.Drawing.Drawing2D; 

namespace WindowsFormsApplication1 
{ 
    public partial class Form1 : Form 
    { 
     public Form1() 
     { 
      InitializeComponent(); 
     } 

     private void Form1_Paint(object sender, PaintEventArgs e) 
     { 
      e.Graphics.SmoothingMode = SmoothingMode.AntiAlias; 

      int Offset = 25; 
      int BoxSize = 100; 
      int GlintSize = (int)((double)BoxSize * ((double)3/(double)4)); 
      Rectangle Circle = new Rectangle(Offset, Offset, BoxSize, BoxSize); 
      Rectangle Glint = new Rectangle(Offset, Offset, GlintSize, GlintSize); 

      //Debug 
      //e.Graphics.FillRectangle(new SolidBrush(Color.Red), Circle); 
      //e.Graphics.FillRectangle(new SolidBrush(Color.BlueViolet), Glint); 

      //Generate Glint 
      GraphicsPath P = new GraphicsPath(); 
      P.AddEllipse(Glint); 
      PathGradientBrush FlareBrush = new PathGradientBrush(P); 
      FlareBrush.CenterColor = Color.FromArgb(255, 255, 255, 255); 
      Color[] colors = { Color.Transparent }; 
      FlareBrush.SurroundColors = colors; 

      e.Graphics.FillEllipse(new SolidBrush(Color.FromArgb(255, 255, 0, 0)), Circle); 
      e.Graphics.FillEllipse(FlareBrush, Glint); 
      e.Graphics.DrawEllipse(new Pen(new SolidBrush(Color.Black), 1F), Circle); 
     } 
    } 
}