C# RichTextBox 制作文本編輯器

本文利用一個簡單的小例子【文本編輯器】，講解RichTextBox的用法，僅供學習分享使用，如有不足之處，還請指正。

Windows窗體中的RichTextBox控件用於顯示，輸入和操作格式化的文本，RichTextBox除了擁有TextBox控件的所有功能外，還可以顯示字體，顏色，鏈接，從文件中讀取和加載圖像，以及查找指定的字符。RichTextBox控件通常用於提供類似字體處理程序（如Microsoft Word）的文本操作和顯示功能。RichTextBox控件可以顯示滾動條，且默認根據需要進行顯示。

涉及知識點：

• SelectionFont 獲取或設置當前選定文本或插入點的字體。
• FontStyle 指定應用到文本的字形信息。
• SelectionAlignment  獲取或設置應用到當前選定內容或插入點的對齊方式。
• SelectionIndent 獲取或設置所選內容開始行的縮進距離（以像素為單位）。
• SelectionCharOffset 獲取或設置控件中的文本是顯示在基線上、作為上標還是作為基線下方的下標。
• SelectionColor 獲取或設置當前選定文本或插入點的文本顏色。
• SelectionBackColor   獲取或設置在 System.Windows.Forms.RichTextBox 控件中選中文本時文本的顏色。
• SelectionBullet 獲取或設置一個值，通過該值指示項目符號樣式是否應用到當前選定內容或插入點。
• Clipboard Paste 粘貼指定剪貼板格式的剪貼板內容【插入圖片時使用】。
• Find 在對搜索應用特定選項的情況下，在 System.Windows.Forms.RichTextBox 控件的文本中搜索位於控件內特定位置的字符串。

效果圖

如下【以下設置文本對應的格式】：

核心代碼

如下

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Drawing.Printing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace DemoRichText.Model
{
    public class DefaultRickFormat : BaseRichFormat
    {
        public override void SetFormat(RichTextBox rtbInfo)
        {

        }
    }

    /// <summary>
    /// 加粗格式
    /// </summary>
    public class BoldRichFormat : BaseRichFormat
    {
        public override void SetFormat(RichTextBox rtbInfo)
        {
            Font oldFont = rtbInfo.SelectionFont;
            Font newFont;
            if (oldFont.Bold)
            {
                newFont = new Font(oldFont, oldFont.Style & ~FontStyle.Bold);//支持位於運算
            }
            else
            {
                newFont = new Font(oldFont, oldFont.Style | FontStyle.Bold);
            }
            rtbInfo.SelectionFont = newFont;
        }
    }

    /// <summary>
    /// 斜體
    /// </summary>
    public class ItalicRichFormat : BaseRichFormat
    {
        public override void SetFormat(RichTextBox rtbInfo)
        {
            Font oldFont = rtbInfo.SelectionFont;
            Font newFont;
            if (oldFont.Italic)
            {
                newFont = new Font(oldFont, oldFont.Style & ~FontStyle.Italic);
            }
            else
            {
                newFont = new Font(oldFont, oldFont.Style | FontStyle.Italic);
            }
            rtbInfo.SelectionFont = newFont;
            rtbInfo.Focus();
        }
    }

    /// <summary>
    /// 下划線
    /// </summary>
    public class UnderLineRichFormat : BaseRichFormat
    {
        public override void SetFormat(RichTextBox rtbInfo)
        {
            Font oldFont = rtbInfo.SelectionFont;
            Font newFont;
            if (oldFont.Underline)
            {
                newFont = new Font(oldFont, oldFont.Style & ~FontStyle.Underline);
            }
            else
            {
                newFont = new Font(oldFont, oldFont.Style | FontStyle.Underline);
            }
            rtbInfo.SelectionFont = newFont;
            rtbInfo.Focus();
        }
    }

    /// <summary>
    /// 刪除線
    /// </summary>
    public class StrikeLineRichFormat : BaseRichFormat
    {
        public override void SetFormat(RichTextBox rtbInfo)
        {
            Font oldFont = rtbInfo.SelectionFont;
            Font newFont;
            if (oldFont.Underline)
            {
                newFont = new Font(oldFont, oldFont.Style & ~FontStyle.Strikeout);
            }
            else
            {
                newFont = new Font(oldFont, oldFont.Style | FontStyle.Strikeout);
            }
            rtbInfo.SelectionFont = newFont;
            rtbInfo.Focus();
        }
    }

    /// <summary>
    /// 左對齊
    /// </summary>
    public class LeftRichFormat : BaseRichFormat
    {
        public override void SetFormat(RichTextBox rtbInfo)
        {
            rtbInfo.SelectionAlignment = HorizontalAlignment.Left;
            rtbInfo.Focus();
        }
    }

    /// <summary>
    /// 居中對齊
    /// </summary>
    public class CenterRichFormat : BaseRichFormat
    {
        public override void SetFormat(RichTextBox rtbInfo)
        {
            if (rtbInfo.SelectionAlignment == HorizontalAlignment.Center)
            {
                rtbInfo.SelectionAlignment = HorizontalAlignment.Left;
            }
            else
            {
                rtbInfo.SelectionAlignment = HorizontalAlignment.Center;
            }

            rtbInfo.Focus();
        }
    }

    /// <summary>
    /// 右對齊
    /// </summary>
    public class RightRichFormat : BaseRichFormat
    {
        public override void SetFormat(RichTextBox rtbInfo)
        {
            if (rtbInfo.SelectionAlignment == HorizontalAlignment.Right)
            {
                rtbInfo.SelectionAlignment = HorizontalAlignment.Left;
            }
            else
            {
                rtbInfo.SelectionAlignment = HorizontalAlignment.Right;
            }

            rtbInfo.Focus();
        }
    }

    /// <summary>
    /// 縮進對齊
    /// </summary>
    public class IndentRichFormat : BaseRichFormat
    {
        public override void SetFormat(RichTextBox rtbInfo)
        {
            //每次以10個像素進行縮進
            rtbInfo.SelectionIndent = rtbInfo.SelectionIndent + 10;
            rtbInfo.Focus();
        }
    }

    /// <summary>
    /// 縮進對齊
    /// </summary>
    public class OutIndentRichFormat : BaseRichFormat
    {
        public override void SetFormat(RichTextBox rtbInfo)
        {
            //每次以10個像素進行縮進
            rtbInfo.SelectionIndent = rtbInfo.SelectionIndent - 10;
            rtbInfo.Focus();
        }
    }

    /// <summary>
    /// 下標
    /// </summary>
    public class SubScriptRichFormat : BaseRichFormat
    {
        public override void SetFormat(RichTextBox rtbInfo)
        {
            if (rtbInfo.SelectionCharOffset < 0)
            {
                rtbInfo.SelectionCharOffset = 0;
            }
            else {
                rtbInfo.SelectionCharOffset = -5;
            }
            rtbInfo.Focus();
        }
    }

    /// <summary>
    /// 上標
    /// </summary>
    public class SuperScriptRichFormat : BaseRichFormat
    {
        public override void SetFormat(RichTextBox rtbInfo)
        {
            if (rtbInfo.SelectionCharOffset > 0)
            {
                rtbInfo.SelectionCharOffset = 0;
            }
            else {
                rtbInfo.SelectionCharOffset = 5;
            }
            rtbInfo.Focus();
        }
    }

    /// <summary>
    /// 字體
    /// </summary>
    public class FontRichFormat : BaseRichFormat
    {
        public override void SetFormat(RichTextBox rtbInfo)
        {
            FontDialog f = new FontDialog();
            if (f.ShowDialog() == DialogResult.OK)
            {
                FontFamily family = f.Font.FontFamily;
                rtbInfo.SelectionFont = new Font(family, rtbInfo.SelectionFont.Size, rtbInfo.SelectionFont.Style);
            }
            rtbInfo.Focus();
        }
    }

    /// <summary>
    /// 文本顏色
    /// </summary>
    public class ForeColorRichFormat : BaseRichFormat
    {
        public override void SetFormat(RichTextBox rtbInfo)
        {
            ColorDialog f = new ColorDialog();
            if (f.ShowDialog() == DialogResult.OK)
            {

                rtbInfo.SelectionColor = f.Color;
            }
            rtbInfo.Focus();
        }
    }

    /// <summary>
    /// 文本背景顏色
    /// </summary>
    public class BgColorRichFormat : BaseRichFormat
    {
        public override void SetFormat(RichTextBox rtbInfo)
        {
            ColorDialog f = new ColorDialog();
            if (f.ShowDialog() == DialogResult.OK)
            {

                rtbInfo.SelectionBackColor = f.Color;
            }
            rtbInfo.Focus();
        }
    }

    /// <summary>
    /// UL列表,項目符號樣式
    /// </summary>
    public class UlRichFormat : BaseRichFormat
    {
        public override void SetFormat(RichTextBox rtbInfo)
        {
            if (rtbInfo.SelectionBullet)
            {
                rtbInfo.SelectionBullet = false;
            }
            else {
                rtbInfo.SelectionBullet = true;
                rtbInfo.BulletIndent = 10;
            }
            rtbInfo.Focus();
        }
    }

    /// <summary>
    /// 圖片插入
    /// </summary>
    public class PicRichFormat : BaseRichFormat
    {
        public override void SetFormat(RichTextBox rtbInfo)
        {
            OpenFileDialog o = new OpenFileDialog();
            o.InitialDirectory = AppDomain.CurrentDomain.BaseDirectory;
            o.Title = "請選擇圖片";
            o.Filter = "jpeg|*.jpeg|jpg|*.jpg|png|*.png|gif|*.gif"; 
            if (o.ShowDialog() == DialogResult.OK) {
                string fileName = o.FileName;
                try
                {
                   Image bmp = Image.FromFile(fileName);
                   Clipboard.SetDataObject(bmp);

                    DataFormats.Format dataFormat = DataFormats.GetFormat(DataFormats.Bitmap);
                    if (rtbInfo.CanPaste(dataFormat))
                    {
                        rtbInfo.Paste(dataFormat);
                    }
                        
                }
                catch (Exception exc)
                {
                    MessageBox.Show("圖片插入失敗。" + exc.Message, "提示",
                                    MessageBoxButtons.OK, MessageBoxIcon.Information);
                }

            }
            rtbInfo.Focus();
        }
    }

    /// <summary>
    /// 刪除
    /// </summary>
    public class DelRichFormat : BaseRichFormat
    {
        public override void SetFormat(RichTextBox rtbInfo)
        {
            rtbInfo.SelectedText = "";
            rtbInfo.Focus();
        }
    }

    /// <summary>
    /// 查找
    /// </summary>
    public class SearchRichFormat : BaseRichFormat
    {
        public override void SetFormat(RichTextBox rtbInfo)
        {
            string find = rtbInfo.Tag.ToString();
            int index=  rtbInfo.Find(find, 0,RichTextBoxFinds.None);
            int startPos = index;
            int nextIndex = 0;
            while (nextIndex != startPos)//循環查找字符串，並用藍色加粗12號Times New Roman標記之  
            {
                rtbInfo.SelectionStart = index;
                rtbInfo.SelectionLength = find.Length;
                rtbInfo.SelectionColor = Color.Blue;
                rtbInfo.SelectionFont = new Font("Times New Roman", (float)12, FontStyle.Bold);
                rtbInfo.Focus();
                nextIndex = rtbInfo.Find(find, index + find.Length, RichTextBoxFinds.None);
                if (nextIndex == -1)//若查到文件末尾，則充值nextIndex為初始位置的值，使其達到初始位置，順利結束循環，否則會有異常。  
                {
                    nextIndex = startPos;
                }
                index = nextIndex;
            }
            rtbInfo.Focus();
        }
    }

    /// <summary>
    /// 打印
    /// </summary>
    public class PrintRichFormat : BaseRichFormat
    {
        private RichTextBox richTextbox;

        public override void SetFormat(RichTextBox rtbInfo)
        {
            this.richTextbox = rtbInfo;
            PrintDocument pd = new PrintDocument();
            pd.PrintPage += new PrintPageEventHandler(pd_PrintPage);
            // 打印文檔
            pd.Print();
        }

        private void pd_PrintPage(object sender, PrintPageEventArgs ev)
        {
            //ev.Graphics.DrawString(richTextbox.Text);
            //ev.HasMorePages = true;
        }
    }

    /// <summary>
    /// 字體大小
    /// </summary>
    public class FontSizeRichFormat : BaseRichFormat
    {
        public override void SetFormat(RichTextBox rtbInfo)
        {
            string fontSize = rtbInfo.Tag.ToString();
            float fsize = 0.0f;
            if (float.TryParse(fontSize, out fsize)) {
                rtbInfo.SelectionFont = new Font(rtbInfo.Font.FontFamily, fsize, rtbInfo.SelectionFont.Style);
            }
            rtbInfo.Focus();
        }
    }
}

頁面代碼【由於實現了代碼封裝，所有頁面代碼較少】

using DemoRichText.Model;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace DemoRichText
{
    public partial class MainForm : Form
    {
        public MainForm()
        {
            InitializeComponent();
        }
        

        public void btnButtonClick(object sender, EventArgs e) {
            Button btn = (Button)sender;
            BTNType btnType;
            if (Enum.TryParse<BTNType>(btn.Tag.ToString(), out btnType)) {
                if (btnType == BTNType.Search) {
                    if (!string.IsNullOrEmpty(this.txtSearch.Text.Trim()))
                    {
                        this.rtbInfo.Tag = this.txtSearch.Text.Trim();
                    }
                    else {
                        return;
                    }
                    
                }
                IRichFormat richFomat = RichFormatFactory.CreateRichFormat(btnType);
                richFomat.SetFormat(this.rtbInfo);
            }
        }

        private void combFontSize_SelectedIndexChanged(object sender, EventArgs e)
        {
            float fsize = 12.0f;
            if (combFontSize.SelectedIndex > -1) {
                if (float.TryParse(combFontSize.SelectedItem.ToString(), out fsize)) {
                    rtbInfo.Tag = fsize.ToString();
                    IRichFormat richFomat = RichFormatFactory.CreateRichFormat(BTNType.FontSize);
                    richFomat.SetFormat(this.rtbInfo);
                }
                return;
            }
        }
    }
}

RichTextBox是一個功能豐富的控件，值得學習。

源碼下載鏈接

源碼鏈接