C# RichTextBox制作文本编辑器

本文利用一个简单的小例子【文本编辑器】，讲解RichTextBox的用法。

Windows窗体中的RichTextBox控件用于显示，输入和操作格式化的文本，RichTextBox除了拥有TextBox控件的所有功能外，还可以显示字体，颜色，链接，从文件中读取和加载图像，以及查找指定的字符。RichTextBox控件通常用于提供类似字体处理程序（如Microsoft Word）的文本操作和显示功能。RichTextBox控件可以显示滚动条，且默认根据需要进行显示。

涉及知识点：

• SelectionFont 获取或设置当前选定文本或插入点的字体。
• FontStyle 指定应用到文本的字形信息。
• SelectionAlignment  获取或设置应用到当前选定内容或插入点的对齐方式。
• SelectionIndent 获取或设置所选内容开始行的缩进距离（以像素为单位）。
• SelectionCharOffset 获取或设置控件中的文本是显示在基线上、作为上标还是作为基线下方的下标。
• SelectionColor 获取或设置当前选定文本或插入点的文本颜色。
• SelectionBackColor   获取或设置在 System.Windows.Forms.RichTextBox 控件中选中文本时文本的颜色。
• SelectionBullet 获取或设置一个值，通过该值指示项目符号样式是否应用到当前选定内容或插入点。
• Clipboard Paste 粘贴指定剪贴板格式的剪贴板内容【插入图片时使用】。
• Find 在对搜索应用特定选项的情况下，在 System.Windows.Forms.RichTextBox 控件的文本中搜索位于控件内特定位置的字符串。
  

效果图如下【以下设置文本对应的格式】：

核心代码如下

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);//支持位于运算
   }
   else
   {
    newFont = new Font(oldFont, oldFont.Style | FontStyle.Bold);
   }
   rtbInfo.SelectionFont = newFont;
  }
 }

 /// <summary>
 /// 斜体
 /// </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>
 /// 下划线
 /// </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>
 /// 删除线
 /// </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>
 /// 左对齐
 /// </summary>
 public class LeftRichFormat : BaseRichFormat
 {
  public override void SetFormat(RichTextBox rtbInfo)
  {
   rtbInfo.SelectionAlignment = HorizontalAlignment.Left;
   rtbInfo.Focus();
  }
 }

 /// <summary>
 /// 居中对齐
 /// </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>
 /// 右对齐
 /// </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>
 /// 缩进对齐
 /// </summary>
 public class IndentRichFormat : BaseRichFormat
 {
  public override void SetFormat(RichTextBox rtbInfo)
  {
   //每次以10个像素进行缩进
   rtbInfo.SelectionIndent = rtbInfo.SelectionIndent + 10;
   rtbInfo.Focus();
  }
 }

 /// <summary>
 /// 缩进对齐
 /// </summary>
 public class OutIndentRichFormat : BaseRichFormat
 {
  public override void SetFormat(RichTextBox rtbInfo)
  {
   //每次以10个像素进行缩进
   rtbInfo.SelectionIndent = rtbInfo.SelectionIndent - 10;
   rtbInfo.Focus();
  }
 }

 /// <summary>
 /// 下标
 /// </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>
 /// 上标
 /// </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>
 /// 字体
 /// </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>
 /// 文本颜色
 /// </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>
 /// 文本背景颜色
 /// </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,项目符号样式
 /// </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>
 /// 图片插入
 /// </summary>
 public class PicRichFormat : BaseRichFormat
 {
  public override void SetFormat(RichTextBox rtbInfo)
  {
   OpenFileDialog o = new OpenFileDialog();
   o.InitialDirectory = AppDomain.CurrentDomain.BaseDirectory;
   o.Title = "请选择图片";
   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("图片插入失败。" + exc.Message, "提示",
         MessageBoxButtons.OK, MessageBoxIcon.Information);
    }

   }
   rtbInfo.Focus();
  }
 }

 /// <summary>
 /// 删除
 /// </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)//循环查找字符串，并用蓝色加粗12号Times New Roman标记之 
   {
    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，则充值nextIndex为初始位置的值，使其达到初始位置，顺利结束循环，否则会有异常。 
    {
     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);
   // 打印文档
   pd.Print();
  }

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

 /// <summary>
 /// 字体大小
 /// </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();
  }
 }
} 

页面代码【由于实现了代码封装，所有页面代码较少】

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是一个功能丰富的控件，值得学习。

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