使用

private void button1_Click(object sender, EventArgs e){    RichTextBoxCtrl.richTextBoxFontClass r = new RichTextBoxCtrl.richTextBoxFontClass();    r.richTextBox = richTextBox1;    r.ToggleBold();}

 

 

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Windows.Forms;using System.Drawing;////使用//RichTextBoxCtrl.richTextBoxFontClass r = new RichTextBoxCtrl.richTextBoxFontClass();//r.richTextBox = richTextBox1;//r.ToggleBold();namespace RichTextBoxCtrl{    class richTextBoxFontClass    {               public richTextBoxFontClass()        {            richTextBox = new RichTextBox();        }        public RichTextBox richTextBox;        //粗体        public void ToggleBold()        {            if (richTextBox.SelectionFont == null)                richTextBox.SelectionFont = richTextBox.Font;            FontStyle style = richTextBox.SelectionFont.Style;            if (richTextBox.SelectionFont.Bold)                style &= ~FontStyle.Bold;//恢复正常            else                style |= FontStyle.Bold;            richTextBox.SelectionFont = new Font(richTextBox.SelectionFont, style);        }        //斜体        public void ToggleItalic()        {            if (richTextBox.SelectionFont == null)                richTextBox.SelectionFont = richTextBox.Font;            FontStyle style = richTextBox.SelectionFont.Style;            if (richTextBox.SelectionFont.Italic)                style &= ~FontStyle.Italic;//恢复正常            else                style |= FontStyle.Italic;            richTextBox.SelectionFont = new Font(richTextBox.SelectionFont, style);        }        //下划线        public void ToggleUnderLine()        {            if (richTextBox.SelectionFont == null)                richTextBox.SelectionFont = richTextBox.Font;            FontStyle style = richTextBox.SelectionFont.Style;            if (richTextBox.SelectionFont.Underline)                style &= ~FontStyle.Underline;//恢复正常            else                style |= FontStyle.Underline;            richTextBox.SelectionFont = new Font(richTextBox.SelectionFont, style);        }        //删除线        public void ToggleStrikeout()        {            if (richTextBox.SelectionFont == null)                richTextBox.SelectionFont = richTextBox.Font;            FontStyle style = richTextBox.SelectionFont.Style;            if (richTextBox.SelectionFont.Strikeout)                style &= ~FontStyle.Strikeout;//恢复正常            else                style |= FontStyle.Strikeout;            richTextBox.SelectionFont = new Font(richTextBox.SelectionFont, style);        }    }}