Create Custom Design for A Tab Control

A little more work involved here than in the previous case, but definately worth it. Add a new UserControl to your project and replace the code with that shown below.
As you can see we have made the BackColor property of the TabControl Visible in the Designer and put a custom background behind Transparent Tabpages. This control has been updated to incorporate a modified version of the SelectedIndexChanging event in code examples by Matt Hinz and Ken Tucker. The project needs a custom designer to get the Design time painting to behave properly, but that's something for a later project. You'll find TabControlEx on my Controls page with all the work already done.

TabControl First Edition

VB net Sample:

Imports System.ComponentModel
Imports System.Runtime.InteropServices
Imports System.Reflection
Public Class TabControl
  Inherits System.Windows.Forms.TabControl
#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
    setstyle(ControlStyles.AllPaintingInWmPaint Or _
      ControlStyles.DoubleBuffer Or _
      ControlStyles.ResizeRedraw Or _
      ControlStyles.UserPaint, True)
  End Sub
  'UserControl1 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
  'Required by the Windows Form Designer
  Private components As System.ComponentModel.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()
    components = New System.ComponentModel.Container
  End Sub
#End Region
#Region " InterOP "
  <StructLayout(LayoutKind.Sequential)> _
  Private Structure NMHDR
    Public HWND As Int32
    Public idFrom As Int32
    Public code As Int32
    Public Overloads Function ToString() As String
    Return String.Format("Hwnd: {0}, ControlID: {1}, Code: {2}", HWND, idFrom, code)
    End Function
  End Structure
  Private Const TCN_FIRST As Int32 = &HFFFFFFFFFFFFFDDA&
  Private Const TCN_SELCHANGING As Int32 = (TCN_FIRST - 2)
  Private Const WM_USER As Int32 = &H400&
  Private Const WM_NOTIFY As Int32 = &H4E&
  Private Const WM_REFLECT As Int32 = WM_USER + &H1C00&
#End Region
#Region " BackColor Manipulation "
  'As well as exposing the property to the Designer we want it to behave just like any other 
  'controls BackColor property so we need some clever manipulation.
  Private m_Backcolor As Color = Color.Empty
  <Browsable(True), _
  Description("The background color used to display text and graphics in a control.")> _
  Public Overrides Property BackColor() As Color
    Get
    If m_Backcolor.Equals(Color.Empty) Then
      If Parent Is Nothing Then
        Return Control.DefaultBackColor
      Else
        Return Parent.BackColor
      End If
    End If
    Return m_Backcolor
    End Get
    Set(ByVal Value As Color)
    If m_Backcolor.Equals(Value) Then Return
    m_Backcolor = Value
    Invalidate()
    'Let the Tabpages know that the backcolor has changed.
    MyBase.OnBackColorChanged(EventArgs.Empty)
    End Set
  End Property
  Public Function ShouldSerializeBackColor() As Boolean
    Return Not m_Backcolor.Equals(Color.Empty)
  End Function
  Public Overrides Sub ResetBackColor()
    m_Backcolor = Color.Empty
    Invalidate()
  End Sub
#End Region
  Protected Overrides Sub OnParentBackColorChanged(ByVal e As System.EventArgs)
    MyBase.OnParentBackColorChanged(e)
    Invalidate()
  End Sub
  Protected Overrides Sub OnSelectedIndexChanged(ByVal e As System.EventArgs)
    MyBase.OnSelectedIndexChanged(e)
    Invalidate()
  End Sub
  Protected Overrides Sub OnPaint(ByVal e As System.Windows.Forms.PaintEventArgs)
    MyBase.OnPaint(e)
    e.Graphics.Clear(BackColor)
    Dim r As Rectangle = Me.ClientRectangle
    If TabCount <= 0 Then Return
    'Draw a custom background for Transparent TabPages
    r = SelectedTab.Bounds
    Dim sf As New StringFormat
    sf.Alignment = StringAlignment.Center
    sf.LineAlignment = StringAlignment.Center
    Dim DrawFont As New Font(Font.FontFamily, 24, FontStyle.Regular, GraphicsUnit.Pixel)
    ControlPaint.DrawStringDisabled(e.Graphics, "Micks Ownerdraw TabControl", DrawFont, BackColor, RectangleF.op_Implicit(r), sf)
    DrawFont.Dispose()
    'Draw a border around TabPage
    r.Inflate(3, 3)
    Dim tp As TabPage = TabPages(SelectedIndex)
    Dim PaintBrush As New SolidBrush(tp.BackColor)
    e.Graphics.FillRectangle(PaintBrush, r)
    ControlPaint.DrawBorder(e.Graphics, r, PaintBrush.Color, ButtonBorderStyle.Outset)
    'Draw the Tabs
    For index As Integer = 0 To TabCount - 1
    tp = TabPages(index)
    r = GetTabRect(index)
    Dim bs As ButtonBorderStyle = ButtonBorderStyle.Outset
    If index = SelectedIndex Then bs = ButtonBorderStyle.Inset
    PaintBrush.Color = tp.BackColor
    e.Graphics.FillRectangle(PaintBrush, r)
    ControlPaint.DrawBorder(e.Graphics, r, PaintBrush.Color, bs)
    PaintBrush.Color = tp.ForeColor
    'Set up rotation for left and right aligned tabs
    If Alignment = TabAlignment.Left Or Alignment = TabAlignment.Right Then
      Dim RotateAngle As Single = 90
      If Alignment = TabAlignment.Left Then RotateAngle = 270
      Dim cp As New PointF(r.Left + (r.Width \ 2), r.Top + (r.Height \ 2))
      e.Graphics.TranslateTransform(cp.X, cp.Y)
      e.Graphics.RotateTransform(RotateAngle)
      r = New Rectangle(-(r.Height \ 2), -(r.Width \ 2), r.Height, r.Width)
    End If
    'Draw the Tab Text
    If tp.Enabled Then
      e.Graphics.DrawString(tp.Text, Font, PaintBrush, RectangleF.op_Implicit(r), sf)
    Else
      ControlPaint.DrawStringDisabled(e.Graphics, tp.Text, Font, tp.BackColor, RectangleF.op_Implicit(r), sf)
    End If
    e.Graphics.ResetTransform()
    Next
    PaintBrush.Dispose()
  End Sub
  <Description("Occurs as a tab is being changed.")> _
  Public Event SelectedIndexChanging As SelectedTabPageChangeEventHandler
  Protected Overrides Sub WndProc(ByRef m As System.Windows.Forms.Message)
    If m.Msg = (WM_REFLECT + WM_NOTIFY) Then
    Dim hdr As NMHDR = DirectCast(Marshal.PtrToStructure(m.LParam, GetType(NMHDR)), NMHDR)
    If hdr.code = TCN_SELCHANGING Then
      Dim tp As TabPage = TestTab(Me.PointToClient(Cursor.Position))
      If Not tp Is Nothing Then
        Dim e As New TabPageChangeEventArgs(Me.SelectedTab, tp)
        RaiseEvent SelectedIndexChanging(Me, e)
        If e.Cancel OrElse tp.Enabled = False Then
        m.Result = New IntPtr(1)
        Return
        End If
      End If
    End If
    End If
    MyBase.WndProc(m)
  End Sub
  Private Function TestTab(ByVal pt As Point) As TabPage
    For index As Integer = 0 To TabCount - 1
    If GetTabRect(index).Contains(pt.X, pt.Y) Then
      Return TabPages(index)
    End If
    Next
    Return Nothing
  End Function
End Class
#Region " EventArgs Class's "
Public Class TabPageChangeEventArgs
  Inherits EventArgs
  Private _Selected As TabPage
  Private _PreSelected As TabPage
  Public Cancel As Boolean = False
  Public ReadOnly Property CurrentTab() As TabPage
    Get
    Return _Selected
    End Get
  End Property
  Public ReadOnly Property NextTab() As TabPage
    Get
    Return _PreSelected
    End Get
  End Property
  Public Sub New(ByVal CurrentTab As TabPage, ByVal NextTab As TabPage)
    _Selected = CurrentTab
    _PreSelected = NextTab
  End Sub
End Class
Public Delegate Sub SelectedTabPageChangeEventHandler(ByVal sender As Object, ByVal e As TabPageChangeEventArgs)
#End Region
        

Csharp Sample:

using System;
using System.Collections;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Windows.Forms;
using System.Runtime.InteropServices;
namespace Dotnetrix_Samples
{
  /// <summary>
  /// Summary description for TabControl.
  /// </summary>
  public class TabControl : System.Windows.Forms.TabControl
  {
    /// <summary> 
    /// Required designer variable.
    /// </summary>
    private System.ComponentModel.Container components = null;
    public TabControl()
    {
    // This call is required by the Windows.Forms Form Designer.
    InitializeComponent();
    // TODO: Add any initialization after the InitializeComponent call
    SetStyle(ControlStyles.AllPaintingInWmPaint | ControlStyles.DoubleBuffer | ControlStyles.ResizeRedraw | ControlStyles.UserPaint, true);
    }

    /// <summary> 
    /// Clean up any resources being used.
    /// </summary>
    protected override void Dispose( bool disposing )
    {
    if( disposing )
    {
      if(components != null)
      {
        components.Dispose();
      }
    }
    base.Dispose( disposing );
    }

    #region Component Designer generated code
    /// <summary> 
    /// Required method for Designer support - do not modify 
    /// the contents of this method with the code editor.
    /// </summary>
    private void InitializeComponent()
    {
    components = new System.ComponentModel.Container();
    }
    #endregion
    #region Interop
    [StructLayout(LayoutKind.Sequential)]
    private struct NMHDR
    {
    public IntPtr HWND;
    public uint idFrom;
    public int code;
    public override String ToString()
    {
      return String.Format("Hwnd: {0}, ControlID: {1}, Code: {2}", HWND, idFrom, code);
    }
    }
    
    private const int TCN_FIRST = 0 - 550;       
    private const int TCN_SELCHANGING = (TCN_FIRST - 2);
    
    private const int WM_USER = 0x400;
    private const int WM_NOTIFY = 0x4E;
    private const int WM_REFLECT = WM_USER + 0x1C00;
    
    #endregion
    #region BackColor Manipulation
    //As well as exposing the property to the Designer we want it to behave just like any other 
    //controls BackColor property so we need some clever manipulation.
    private Color m_Backcolor = Color.Empty;
    [Browsable(true),Description("The background color used to display text and graphics in a control.")]
    public override Color BackColor
    {
    get
    {
      if (m_Backcolor.Equals(Color.Empty))
      {
        if (Parent == null)
        return Control.DefaultBackColor;
        else
        return Parent.BackColor;
      }
      return m_Backcolor;
    }
    set
    {
      if (m_Backcolor.Equals(value)) return;
      m_Backcolor = value;
      Invalidate();
      //Let the Tabpages know that the backcolor has changed.
      base.OnBackColorChanged(EventArgs.Empty);
    }
    }
    public bool ShouldSerializeBackColor()
    {
    return !m_Backcolor.Equals(Color.Empty);
    }
    public override void ResetBackColor()
    {
    m_Backcolor = Color.Empty;
    Invalidate();
    }
    #endregion
    protected override void OnParentBackColorChanged(EventArgs e)
    {
    base.OnParentBackColorChanged (e);
    Invalidate();
    }

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

    protected override void OnPaint(PaintEventArgs e)
    {
    base.OnPaint (e);
    e.Graphics.Clear(BackColor);
    Rectangle r = ClientRectangle;
    if (TabCount <= 0) return;
    //Draw a custom background for Transparent TabPages
    r = SelectedTab.Bounds;
    StringFormat sf = new StringFormat();
    sf.Alignment = StringAlignment.Center;
    sf.LineAlignment = StringAlignment.Center;
    Font DrawFont = new Font(Font.FontFamily, 24, FontStyle.Regular, GraphicsUnit.Pixel);
    ControlPaint.DrawStringDisabled(e.Graphics, "Micks Ownerdraw TabControl", DrawFont, BackColor, (RectangleF)r, sf);
    DrawFont.Dispose();
    //Draw a border around TabPage
    r.Inflate(3, 3);
    TabPage tp = TabPages[SelectedIndex];
    SolidBrush PaintBrush = new SolidBrush(tp.BackColor);
    e.Graphics.FillRectangle(PaintBrush, r);
    ControlPaint.DrawBorder(e.Graphics, r, PaintBrush.Color, ButtonBorderStyle.Outset);
    //Draw the Tabs
    for (int index = 0; index <= TabCount - 1; index++)
    {
      tp = TabPages[index];
      r = GetTabRect(index);
      ButtonBorderStyle bs = ButtonBorderStyle.Outset;
      if (index == SelectedIndex) bs = ButtonBorderStyle.Inset;
      PaintBrush.Color = tp.BackColor;
      e.Graphics.FillRectangle(PaintBrush, r);
      ControlPaint.DrawBorder(e.Graphics, r, PaintBrush.Color, bs);
      PaintBrush.Color = tp.ForeColor;
      //Set up rotation for left and right aligned tabs
      if (Alignment == TabAlignment.Left || Alignment == TabAlignment.Right)
      {
        float RotateAngle = 90;
        if (Alignment == TabAlignment.Left) RotateAngle = 270;
        PointF cp = new PointF(r.Left + (r.Width >> 1), r.Top + (r.Height >> 1));
        e.Graphics.TranslateTransform(cp.X, cp.Y);
        e.Graphics.RotateTransform(RotateAngle);
        r = new Rectangle(-(r.Height >> 1), -(r.Width >> 1), r.Height, r.Width);
      }
      //Draw the Tab Text
      if (tp.Enabled)
        e.Graphics.DrawString(tp.Text, Font, PaintBrush, (RectangleF)r, sf);
      else
        ControlPaint.DrawStringDisabled(e.Graphics, tp.Text, Font, tp.BackColor, (RectangleF)r, sf);
      
      e.Graphics.ResetTransform();
    }
    PaintBrush.Dispose();
    }

    [Description("Occurs as a tab is being changed.")]
    public event SelectedTabPageChangeEventHandler SelectedIndexChanging;
    protected override void WndProc(ref Message m)
    {
    if (m.Msg == (WM_REFLECT + WM_NOTIFY))
    {
      NMHDR hdr = (NMHDR)(Marshal.PtrToStructure(m.LParam, typeof(NMHDR)));
      if (hdr.code == TCN_SELCHANGING)
      {
        TabPage tp = TestTab(PointToClient(Cursor.Position));
        if (tp != null)
        {
        TabPageChangeEventArgs e = new TabPageChangeEventArgs(SelectedTab, tp);
        if (SelectedIndexChanging != null)
          SelectedIndexChanging(this, e);
        if (e.Cancel || tp.Enabled == false)
        {
          m.Result = new IntPtr(1);
          return;
        }
        }
      }
    }
    base.WndProc (ref m);
    }

    private TabPage TestTab(Point pt)
    {
    for (int index = 0; index <= TabCount - 1; index++)
    {
      if (GetTabRect(index).Contains(pt.X, pt.Y))
        return TabPages[index];
    }
    return null;
    }
    
  }

  public class TabPageChangeEventArgs : EventArgs
  {
    private TabPage _Selected = null;
    private TabPage _PreSelected = null;
    public bool Cancel = false;
    public TabPage CurrentTab
    {
    get
    {
      return _Selected;
    }
    }

    public  TabPage NextTab
    {
    get
    {
      return _PreSelected;
    }
    }

    public TabPageChangeEventArgs(TabPage CurrentTab, TabPage NextTab)
    {
    _Selected = CurrentTab;
    _PreSelected = NextTab;
    }

  }

  public delegate void SelectedTabPageChangeEventHandler(Object sender, TabPageChangeEventArgs e);
}
        

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TabControl Second Edition

• Download C# and VB.Net Demo Source Code - 181.9 KB
• Download C++ Dll Source Code - 2.03 MB
• Download Compiled CustomTabControl Assembly - 18.33 KB

For more complete examples see the following articles on codeproject:
Painting Your Own Tabs - First Edition
Painting Your Own Tabs - Second Edition