RTF 格式文本的打开、显示、关键字搜索、替换、保存

使用C# 自带的控件实现 RTF 格式文本的打开、显示、关键字搜索、替换、保存，适合C#初学对控件、字符串操作的理解

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Text.Regularexpressions;

namespace BetrayRTFDocument
{
    public partial class Form1 : Form
    {
        private bool flag = false;
        public Form1（）
        {
            InitializeComponent（）;
            btnOpenFile.Click += BtnOpenFile_Click;
            btnSaveFile.Click += BtnSaveFile_Click;
            btnCleanBox.Click += BtnCleanBox_Click;
            btnExit.Click += BtnExit_Click;
            this.Load += Form1_Load;
            rtxtbox.TextChanged += Rtxtbox_TextChanged;
            CutToolStripMenuItem.Click += CutToolStripMenuItem_Click;
            

 属性            大小     日期    时间   名称
----------- ---------  ---------- -----  ----

     文件     146273  2018-07-03 22:57  BetrayRTFDocument\.NET_framework_EULA.rtf

     文件        192  2018-09-09 08:55  BetrayRTFDocument\.vs\BetrayRTFDocument\DesignTimeBuild\.dtbcache

    ..A..H.     32256  2018-09-09 08:55  BetrayRTFDocument\.vs\BetrayRTFDocument\v15\.suo

     文件          0  2018-09-08 11:22  BetrayRTFDocument\.vs\BetrayRTFDocument\v15\Server\sqlite3\db.lock

     文件     565248  2018-09-09 08:55  BetrayRTFDocument\.vs\BetrayRTFDocument\v15\Server\sqlite3\storage.ide

     文件       3397  2018-09-08 15:50  BetrayRTFDocument\BetrayRTFDocument\BetrayRTFDocument.csproj

     文件      14848  2018-09-08 23:52  BetrayRTFDocument\BetrayRTFDocument\bin\Debug\BetrayRTFDocument.exe

     文件      26112  2018-09-08 23:52  BetrayRTFDocument\BetrayRTFDocument\bin\Debug\BetrayRTFDocument.pdb

     文件       4971  2018-09-08 23:53  BetrayRTFDocument\BetrayRTFDocument\Form1.cs

     文件      11654  2018-09-08 23:51  BetrayRTFDocument\BetrayRTFDocument\Form1.Designer.cs

     文件       6430  2018-09-08 23:51  BetrayRTFDocument\BetrayRTFDocument\Form1.resx

     文件         42  2018-09-08 11:22  BetrayRTFDocument\BetrayRTFDocument\obj\Debug\BetrayRTFDocument.csproj.CoreCompileInputs.cache

     文件       1099  2018-09-08 16:21  BetrayRTFDocument\BetrayRTFDocument\obj\Debug\BetrayRTFDocument.csproj.FileListAbsolute.txt

     文件       1012  2018-09-08 23:51  BetrayRTFDocument\BetrayRTFDocument\obj\Debug\BetrayRTFDocument.csproj.GenerateResource.cache

     文件      10576  2018-09-08 11:22  BetrayRTFDocument\BetrayRTFDocument\obj\Debug\BetrayRTFDocument.csprojAssemblyReference.cache

     文件      14848  2018-09-08 23:52  BetrayRTFDocument\BetrayRTFDocument\obj\Debug\BetrayRTFDocument.exe

     文件        180  2018-09-08 23:51  BetrayRTFDocument\BetrayRTFDocument\obj\Debug\BetrayRTFDocument.Form1.resources

     文件      26112  2018-09-08 23:52  BetrayRTFDocument\BetrayRTFDocument\obj\Debug\BetrayRTFDocument.pdb

     文件        180  2018-09-08 15:50  BetrayRTFDocument\BetrayRTFDocument\obj\Debug\BetrayRTFDocument.Properties.Resources.resources

     文件       6959  2018-09-08 11:22  BetrayRTFDocument\BetrayRTFDocument\obj\Debug\DesignTimeResolveAssemblyReferencesInput.cache

     文件        498  2018-09-08 11:22  BetrayRTFDocument\BetrayRTFDocument\Program.cs

     文件       1350  2018-09-08 11:22  BetrayRTFDocument\BetrayRTFDocument\Properties\AssemblyInfo.cs

     文件       2847  2018-09-08 11:22  BetrayRTFDocument\BetrayRTFDocument\Properties\Resources.Designer.cs

     文件       5612  2018-09-08 11:22  BetrayRTFDocument\BetrayRTFDocument\Properties\Resources.resx

     文件       1104  2018-09-08 11:22  BetrayRTFDocument\BetrayRTFDocument\Properties\Settings.Designer.cs

     文件        249  2018-09-08 11:22  BetrayRTFDocument\BetrayRTFDocument\Properties\Settings.settings

     文件       1150  2018-09-08 11:22  BetrayRTFDocument\BetrayRTFDocument.sln

     目录          0  2018-10-29 12:12  BetrayRTFDocument\.vs\BetrayRTFDocument\v15\Server\sqlite3

     目录          0  2018-10-29 12:12  BetrayRTFDocument\.vs\BetrayRTFDocument\v15\Server

     目录          0  2018-09-08 11:22  BetrayRTFDocument\BetrayRTFDocument\obj\Debug\TempPE

............此处省略14个文件信息