RichTextBoxExtended

#region Keyboard shortcuts - Added by chopeen
private void rtb1_KeyDown(object sender, System.Windows.Forms.KeyEventArgs e)
{
  if (e.Modifiers == Keys.Control)
  {
    ToolBarButtonClickEventArgs args = null;

    switch (e.KeyCode)
    {
      case Keys.B:
        args = new ToolBarButtonClickEventArgs(this.tbbBold);
        break;
      case Keys.I:
        args = new ToolBarButtonClickEventArgs(this.tbbItalic);
        break;
      case Keys.S:
        args = new ToolBarButtonClickEventArgs(this.tbbStamp);
        break;
      case Keys.U:
        args = new ToolBarButtonClickEventArgs(this.tbbUnderline);
        break;
      /* this is a default shortcut; no need to define it again
      case Keys.Z:
        args = new ToolBarButtonClickEventArgs(this.tbbUndo);
        break; */
      case Keys.OemMinus:
        args = new ToolBarButtonClickEventArgs(this.tbbStrikeout);
        break;
    }

    if (args != null)
    {
      tb1_ButtonClick(null, args);
    }
  }
}

private void rtb1_KeyPress(object sender, System.Windows.Forms.KeyPressEventArgs e)
{
  switch ((int) e.KeyChar)
  {   // Ctrl+I inserts a tab (char HT) into a textbox
    case 9:
      e.Handled = true;
      break;
  }
}
#endregion

<br />
args.Button.Pushed = !args.Button.Pushed;<br />

#region Change font style
/// <summary>
///     Change the richtextbox style for the current selection
/// </summary>
public void ChangeFontStyle(FontStyle style, bool add)
{
    //This method should handle cases that occur when multiple fonts/styles are selected
    // Parameters:-
    //  style - eg FontStyle.Bold
    //  add - IF true then add else remove

    // throw error if style isn't: bold, italic, strikeout or underline
    if (   style != FontStyle.Bold
        && style != FontStyle.Italic
        && style != FontStyle.Strikeout
        && style != FontStyle.Underline)
            throw new  System.InvalidProgramException("Invalid style parameter to ChangeFontStyle");

    int rtb1start = rtb1.SelectionStart;
    int len = rtb1.SelectionLength;
    int rtbTempStart = 0;

    //if len <= 1 and there is a selection font then just handle and return
    if(len <= 1 && rtb1.SelectionFont != null)
    {
        //add or remove style
        if (add)
            rtb1.SelectionFont = new Font(rtb1.SelectionFont, rtb1.SelectionFont.Style | style);
        else
            rtb1.SelectionFont = new Font(rtb1.SelectionFont, rtb1.SelectionFont.Style & ~style);

        return;
    }

    // Step through the selected text one char at a time
    rtbTemp.Rtf = rtb1.SelectedRtf;
    for(int i = 0; i < len; ++i)
    {
        rtbTemp.Select(rtbTempStart + i, 1);

        //add or remove style
        if (add)
            rtbTemp.SelectionFont = new Font(rtbTemp.SelectionFont, rtbTemp.SelectionFont.Style | style);
        else
            rtbTemp.SelectionFont = new Font(rtbTemp.SelectionFont, rtbTemp.SelectionFont.Style & ~style);
    }

    // Replace & reselect
    rtbTemp.Select(rtbTempStart,len);
    rtb1.SelectedRtf = rtbTemp.SelectedRtf;
    rtb1.Select(rtb1start,len);
    return;
}
#endregion

#region Change font size
/// <summary>
///     Change the richtextbox font size for the current selection
/// </summary>
public void ChangeFontSize(float fontSize)
{
    //This method should handle cases that occur when multiple fonts/styles are selected
    // Parameters:-
    // fontSize - the fontsize to be applied, eg 33.5

    if (fontSize <= 0.0)
        throw new System.InvalidProgramException("Invalid font size parameter to ChangeFontSize");

    int rtb1start = rtb1.SelectionStart;
    int len = rtb1.SelectionLength;
    int rtbTempStart = 0;

    // If len <= 1 and there is a selection font, amend and return
    if (len <= 1 && rtb1.SelectionFont != null)
    {
        rtb1.SelectionFont =
            new Font(rtb1.SelectionFont.FontFamily, fontSize, rtb1.SelectionFont.Style);
        return;
    }

    // Step through the selected text one char at a time
    rtbTemp.Rtf = rtb1.SelectedRtf;
    for(int i = 0; i < len; ++i)
    {
        rtbTemp.Select(rtbTempStart + i, 1);
        rtbTemp.SelectionFont = new Font(rtbTemp.SelectionFont.FontFamily, fontSize, rtbTemp.SelectionFont.Style);
    }

    // Replace & reselect
    rtbTemp.Select(rtbTempStart,len);
    rtb1.SelectedRtf = rtbTemp.SelectedRtf;
    rtb1.Select(rtb1start,len);
    return;
}
#endregion

#region Change font color
/// <summary>
///     Change the richtextbox font color for the current selection
/// </summary>
public void ChangeFontColor(Color newColor)
{
    //This method should handle cases that occur when multiple fonts/styles are selected
    // Parameters:-
    //  newColor - eg Color.Red

    int rtb1start = rtb1.SelectionStart;
    int len = rtb1.SelectionLength;
    int rtbTempStart = 0;

    //if len <= 1 and there is a selection font then just handle and return
    if(len <= 1 && rtb1.SelectionFont != null)
    {
        rtb1.SelectionColor = newColor;
        return;
    }

    // Step through the selected text one char at a time
    rtbTemp.Rtf = rtb1.SelectedRtf;
    for(int i = 0; i < len; ++i)
    {
        rtbTemp.Select(rtbTempStart + i, 1);

        //change color
        rtbTemp.SelectionColor = newColor;
    }

    // Replace & reselect
    rtbTemp.Select(rtbTempStart,len);
    rtb1.SelectedRtf = rtbTemp.SelectedRtf;
    rtb1.Select(rtb1start,len);
    return;
}
#endregion

#region Get Font Details
/// <summary>
///     Returns a Font with:
///     1) The font applying to the entire selection, if none is the default font.
///     2) The font size applying to the entire selection, if none is the size of the default font.
///     3) A style containing the attributes that are common to the entire selection, default regular.
/// </summary>
///
public Font GetFontDetails()
{
    //This method should handle cases that occur when multiple fonts/styles are selected

    int rtb1start = rtb1.SelectionStart;
    int len = rtb1.SelectionLength;
    int rtbTempStart = 0;

    if (len <= 1)
    {
        // Return the selection or default font
        if (rtb1.SelectionFont != null)
            return rtb1.SelectionFont;
        else
            return rtb1.Font;
    }

    // Step through the selected text one char at a time
    // after setting defaults from first char
    rtbTemp.Rtf = rtb1.SelectedRtf;

    //Turn everything on so we can turn it off one by one
    FontStyle replystyle =
        FontStyle.Bold | FontStyle.Italic | FontStyle.Strikeout | FontStyle.Underline;

    // Set reply font, size and style to that of first char in selection.
    rtbTemp.Select(rtbTempStart, 1);
    string replyfont = rtbTemp.SelectionFont.Name;
    float replyfontsize = rtbTemp.SelectionFont.Size;
    replystyle = replystyle & rtbTemp.SelectionFont.Style;

    // Search the rest of the selection
    for(int i = 1; i < len; ++i)
    {
        rtbTemp.Select(rtbTempStart + i, 1);

        // Check reply for different style
        replystyle = replystyle & rtbTemp.SelectionFont.Style;

        // Check font
        if (replyfont != rtbTemp.SelectionFont.FontFamily.Name)
            replyfont = "";

        // Check font size
        if (replyfontsize != rtbTemp.SelectionFont.Size)
            replyfontsize = (float)0.0;
    }

    // Now set font and size if more than one font or font size was selected
    if (replyfont == "")
        replyfont = rtbTemp.Font.FontFamily.Name;

    if (replyfontsize == 0.0)
        replyfontsize = rtbTemp.Font.Size;

    // generate reply font
    Font reply
        = new Font(replyfont, replyfontsize, replystyle);

    return reply;
}
#endregion

#region Keyboard shortcuts - Added by chopeen
private void rtb1_KeyDown(object sender, System.Windows.Forms.KeyEventArgs e)
{
  if (e.Modifiers == Keys.Control)
  {
    ToolBarButtonClickEventArgs args = null;

    switch (e.KeyCode)
    {
      case Keys.B:
        args = new ToolBarButtonClickEventArgs(this.tbbBold);
        break;
      case Keys.I:
        args = new ToolBarButtonClickEventArgs(this.tbbItalic);
        break;
      case Keys.S:
        args = new ToolBarButtonClickEventArgs(this.tbbStamp);
        break;
      case Keys.U:
        args = new ToolBarButtonClickEventArgs(this.tbbUnderline);
        break;
      /* this is a default shortcut; no need to define it again
      case Keys.Z:
        args = new ToolBarButtonClickEventArgs(this.tbbUndo);
        break; */
      case Keys.OemMinus:
        args = new ToolBarButtonClickEventArgs(this.tbbStrikeout);
        break;
    }

    if (args != null)
    {
        args.Button.Pushed = !args.Button.Pushed;
        tb1_ButtonClick(null, args);
    }
  }
}

private void rtb1_KeyPress(object sender, System.Windows.Forms.KeyPressEventArgs e)
{
  switch ((int) e.KeyChar)
  {   // Ctrl+I inserts a tab (char HT) into a textbox
    case 9:
        e.Handled = true;
      break;
  }
}
#endregion

<br />
this.rtb1.KeyDown += new System.Windows.Forms.KeyEventHandler(this.rtb1_KeyDown);<br />
this.rtb1.KeyPress += new System.Windows.Forms.KeyPressEventHandler(this.rtb1_KeyPress);<br />