C# 读写TXT文件操作

原创已于 2024-05-05 13:02:48 修改 · 1w 阅读

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于 2024-05-04 21:03:09 首次发布

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C# 文本文件操作

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一、读取文本文件有多种方法

1 使用 StreamReader 类打开、读取和关闭文本文件。使用 ReadLine 方法逐行读取文本文件，ReadToEnd方法将文本文件读取到末尾。

        /// <summary>
        /// 逐行将文本文件读取到末尾
        /// </summary>
        /// <param name="pathAName"></param>
        /// <returns></returns>
        public static string ReadTXT_StreamReader(string pathAName)
        {
            StreamReader ObjectName = new StreamReader(pathAName);
            return ObjectName.ReadToEnd(); 
        }

2、StreamReader继承TextReader，操作和StreamReader一致，使用 ReadLine 方法逐行读取文本文件，ReadToEnd方法将文本文件读取到末尾。

        /// <summary>
        /// 逐行读取文件,返回列表
        /// </summary>
        /// <param name="pathAName"></param>
        /// <returns></returns>
        public static List<string> ReadTXT_TextReader(string pathAName)
        {
            List<string> txtContent = new List<string>();
            if (!File.Exists(pathAName))
            {
                using (TextReader reader = new StreamReader(pathAName))
                {
                    string line;
                    while ((line = reader.ReadLine()) != null) // 逐行读取文件内容
                    {
                        txtContent.Add(line); // 输出每行内容到控制台
                    }
                }
            }
            return txtContent;
        }

3、使用 File 类打开、读取和关闭文本文件。
File.ReadAllLines(string path, Encoding encoding) 方法：打开一个文件，使用指定的编码读取文件的所有行，然后关闭该文件。返回包含文件所有行的字符串数组。

        /// <summary>
        /// 逐行读取文件,返回数组
        /// </summary>
        /// <param name="pathAName"></param>
        /// <returns></returns>
        public static string[] ReadTXT_ReadAllLines(string pathAName)
        {
            string[] txtContent = null;
            txtContent = System.IO.File.ReadAllLines(pathAName, Encoding.UTF8);
            return txtContent;
        }

File.ReadAllText(string path, Encoding encoding)方法：打开一个文件，使用指定的编码读取文件的所有行，然后关闭该文件。逐行读取文本文件。返回包含文件所有行的字符串。

        /// <summary>
        /// 读取,返回字符串
        /// </summary>
        /// <param name="pathAName"></param>
        /// <returns></returns>
        public static string ReadTXT_ReadAllText(string pathAName)
        {
            string txtContent = null;
            txtContent = System.IO.File.ReadAllText(pathAName, Encoding.UTF8);
            return txtContent;
        }

ReadLines(string path, Encoding encoding)方法：读取具有指定编码的文件的文本行。返回该文件的所有行或查询所示的行。

        /// <summary>
        /// 读取,返回枚举类型
        /// 高效地逐行读取大型文本文件的最佳方法
        /// </summary>
        /// <param name="pathAName"></param>
        /// <returns></returns>
        public static string ReadTXT_ReadLines(string pathAName)
        {
            IEnumerable<string> line = System.IO.File.ReadLines(pathAName, Encoding.UTF8);
            return String.Join(Environment.NewLine, line);
        }

二、创建、写入文本文件

1、FileStream 创建文件，可设置文件属性，StreamWriter 打开、写入、关闭文件。
a）方式1：

        /// <summary>
        /// 数据流形式写入文件
        /// </summary>
        /// <param name="path"></param>
        /// <param name="txtContent"></param>
        /// <returns></returns>
        public static void WriteTXT_StreamWriter(string pathAName, string txtContent)
        {
            FileStream fs;
            //判断是否已经有了这个文件
            if (!System.IO.File.Exists(pathAName))
            {
                //没有则创建这个文件,创建写入文件，设置文件属性为隐藏
                fs = new FileStream(pathAName, FileMode.Create, FileAccess.Write);
            }
            else
            {
                fs = new FileStream(pathAName, FileMode.Open, FileAccess.Write);
            }
            File.SetAttributes(@pathAName, FileAttributes.Hidden);
            StreamWriter sw = new StreamWriter(fs);
            sw.WriteLine(txtContent.Trim());//写入值
            sw.Flush();
            sw.Dispose();
            sw.Close();
            fs.Close();
        }

b）方式2

        /// <summary>
        /// 数据流形式写入文件
        /// </summary>
        /// <param name="pathAName"></param>
        /// <param name="Logstring"></param>
        public static void Write(string pathAName, string Logstring)
        {
            if (!File.Exists(pathAName))
            {
                //创建.txt文件
                FileStream stream = File.Create(pathAName);
                stream.Close();
                stream.Dispose();
            }
            // true：若文件存在，则将数据追加到该文件中若要覆盖该文件
            using (StreamWriter writer = new StreamWriter(pathAName, true))
            {
                //写入文件
                writer.WriteLine(Logstring);
                writer.Close();
            }
        }

2、StreamWriter 继承 TextWriter ，StreamWriter 创建、打开、WriteLine 写入文件

        /// <summary>
        /// 创建、写入文本文档
        /// </summary>
        /// <param name="pathAName"></param>
        /// <param name="Logstring"></param>
        public static void WriteTXT_TextWriter(string pathAName, string Logstring)
        {
            if (!File.Exists(pathAName))
            {
                using (TextWriter reader = new StreamWriter(pathAName))
                {
                    reader.WriteLine(Logstring.Trim());    
                }
            }
        }

3、使用 File 类创建、写入和关闭文本文件
WriteAllText(string path, string contents) 方法：创建一个新文件，在其中写入指定的字符串，然后关闭文件。如果目标文件已存在，则覆盖该文件。

        /// <summary>
        /// 在最开始位置追加，追加到开头
        /// </summary>
        /// <param name="pathAName"></param>
        /// <param name="Logstring"></param>
        public static void AddTextFirst(string pathAName, string Logstring)
        {
            string s = File.ReadAllText(pathAName);
            s = s.Insert(0, Logstring.Trim() + "\r\n");
            File.WriteAllText(pathAName, s);
        }

WriteAllLines(string path, string[] contents) ：创建一个新文件，在其中写入指定的字符串数组，然后关闭该文件。

        /// <summary>
        /// File.WriteAllLines 方法用于将字符串数组的内容按行写入文本文件。
        /// 每个数组元素都被写入文件的一行，且方法会自动在每行的末尾添加换行符。
        /// </summary>
        /// <param name="Logstring"></param>
        /// <param name="pathAName"></param>
        public static void WriteTXT(string pathAName,string []Logstring)
        {
            File.WriteAllLines(pathAName, Logstring);//写入文件
        }

4、在最开始位置追加，追加到开头

        /// <summary>
        /// 在最开始位置追加，追加到开头
        /// </summary>
        /// <param name="pathAName"></param>
        /// <param name="Logstring"></param>
        public static void AddTextFirst(string pathAName, string Logstring)
        {
            string s = File.ReadAllText(pathAName);
            s = s.Insert(0, Logstring.Trim() + "\r\n");
            File.WriteAllText(pathAName, s);
        }

5、在最后位置追加

        /// <summary>
        /// 在最后位置追加
        /// </summary>
        /// <param name="pathAName"></param>
        /// <param name="Logstring"></param>
        public static void AddTextEnd(string pathAName, string Logstring)
        {
            StreamWriter sw = File.AppendText(pathAName);
            sw.WriteLine(Logstring.Trim());
            sw.Close();
        }

三、使用实例

        OpenFileDialog openFileDialog1;
        SaveFileDialog saveFileOpen;
        string dir = null;
        public Form1()
        {
            InitializeComponent();
            dir = Environment.GetFolderPath(Environment.SpecialFolder.DesktopDirectory);
            openFileDialog1 = new OpenFileDialog();
            openFileDialog1.Title = "导入";
            openFileDialog1.Filter = "TXT文件|*.txt";
            openFileDialog1.Multiselect = false;
            openFileDialog1.RestoreDirectory = true;
            openFileDialog1.InitialDirectory = dir;

            saveFileOpen = new SaveFileDialog();
            saveFileOpen.Title = "保存文件";
            saveFileOpen.Filter = "TXT文件(*.txt)|*.txt";
            saveFileOpen.RestoreDirectory = true;
            saveFileOpen.InitialDirectory = dir;
        }
        private void richTextBox1_TextChanged(object sender, EventArgs e)
        {
            richTextBox1.ScrollToCaret();
        }
        /// <summary>
        /// 读入txt文件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button1_Click(object sender, EventArgs e)
        {
            string info = null;
            string txtContent = null;
            if (openFileDialog1.ShowDialog() == DialogResult.OK)
            {
                info = openFileDialog1.FileName;
            }
            if (!string.IsNullOrEmpty(info))
            {
                txtContent = OperateTXT.ReadTXT_StreamReader(info);
                richTextBox1.AppendText(txtContent);
            }
        }
        /// <summary>
        /// 写入txt文件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button2_Click(object sender, EventArgs e)
        {
            string dir = Environment.GetFolderPath(Environment.SpecialFolder.DesktopDirectory);
            string now_date = DateTime.Now.ToString("MMddHHmmss") + ".txt";
            string newPath = System.IO.Path.Combine(dir, now_date);

            saveFileOpen.FileName = newPath; //设置默认另存为的名字
            if (saveFileOpen.ShowDialog() == DialogResult.OK)
            {
                newPath = saveFileOpen.FileName;
            }
            OperateTXT.WriteTxt(newPath, richTextBox1.Text);
        }

在这里插入图片描述
静态操作使用类

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace FileOperationsDemo
{
    public static class OperateTXT
    {
        #region 写入文件
        /// <summary>
        /// 数据流形式写入文件
        /// </summary>
        /// <param name="path"></param>
        /// <param name="txtContent"></param>
        /// <returns></returns>
        public static void WriteTXT_StreamWriter(string pathAName, string txtContent)
        {
            FileStream fs;
            //判断是否已经有了这个文件
            if (!System.IO.File.Exists(pathAName))
            {
                //没有则创建这个文件,创建写入文件，设置文件属性为隐藏
                fs = new FileStream(pathAName, FileMode.Create, FileAccess.Write);
            }
            else
            {
                fs = new FileStream(pathAName, FileMode.Open, FileAccess.Write);
            }
            File.SetAttributes(@pathAName, FileAttributes.Hidden);
            StreamWriter sw = new StreamWriter(fs);
            sw.WriteLine(txtContent.Trim());//写入值
            sw.Flush();
            sw.Dispose();
            sw.Close();
            fs.Close();
        }
        /// <summary>
        /// 数据流形式写入文件
        /// </summary>
        /// <param name="pathAName"></param>
        /// <param name="Logstring"></param>
        public static void Write(string pathAName, string Logstring)
        {
            if (!File.Exists(pathAName))
            {
                //创建.txt文件
                FileStream stream = File.Create(pathAName);
                stream.Close();
                stream.Dispose();
            }
            // true：若文件存在，则将数据追加到该文件中若要覆盖该文件
            using (StreamWriter writer = new StreamWriter(pathAName, true))
            {
                //写入文件
                writer.WriteLine(Logstring);
                writer.Close();
            }
        }
        /// <summary>
        /// 创建、写入文本文档
        /// </summary>
        /// <param name="pathAName"></param>
        /// <param name="Logstring"></param>
        public static void WriteTXT_TextWriter(string pathAName, string Logstring)
        {
            if (!File.Exists(pathAName))
            {
                using (TextWriter reader = new StreamWriter(pathAName))
                {
                    reader.WriteLine(Logstring.Trim());    
                }
            }
        }
        /// <summary> 
        /// File.WriteAllText 方法用于将单个字符串写入文本文件。
        /// 整个字符串将写入文件，不会自动添加换行符。
        /// 如果需要在字符串中包含换行，需要手动添加换行符。
        /// </summary>
        /// <param name="Logstring"></param>
        /// <param name="pathAName"></param>
        public static void WriteTxt(string pathAName, string Logstring)
        {
            File.WriteAllText(pathAName, Logstring);//写入文件
        }
        /// <summary>
        /// File.WriteAllLines 方法用于将字符串数组的内容按行写入文本文件。
        /// 每个数组元素都被写入文件的一行，且方法会自动在每行的末尾添加换行符。
        /// </summary>
        /// <param name="Logstring"></param>
        /// <param name="pathAName"></param>
        public static void WriteTXT(string pathAName,string []Logstring)
        {
            File.WriteAllLines(pathAName, Logstring);//写入文件
        }
        /// <summary>
        /// 在最开始位置追加，追加到开头
        /// </summary>
        /// <param name="pathAName"></param>
        /// <param name="Logstring"></param>
        public static void AddTextFirst(string pathAName, string Logstring)
        {
            string s = File.ReadAllText(pathAName);
            s = s.Insert(0, Logstring.Trim() + "\r\n");
            File.WriteAllText(pathAName, s);
        }
        /// <summary>
        /// 在最后位置追加
        /// </summary>
        /// <param name="pathAName"></param>
        /// <param name="Logstring"></param>
        public static void AddTextEnd(string pathAName, string Logstring)
        {
            StreamWriter sw = File.AppendText(pathAName);
            sw.WriteLine(Logstring.Trim());
            sw.Close();
        }
        #endregion

        #region 读取文件
        /// <summary>
        /// 将文本文件读取到末尾
        /// </summary>
        /// <param name="pathAName"></param>
        /// <returns></returns>
        public static string ReadTXT_StreamReader(string pathAName)
        {
            StreamReader ObjectName = new StreamReader(pathAName); 
            return ObjectName.ReadToEnd();
        }
        /// <summary>
        /// 逐行读取文件,返回列表
        /// </summary>
        /// <param name="pathAName"></param>
        /// <returns></returns>
        public static List<string> ReadTXT_TextReader(string pathAName)
        {
            List<string> txtContent = new List<string>();
            if (!File.Exists(pathAName))
            {
                using (TextReader reader = new StreamReader(pathAName))
                {
                    string line;
                    while ((line = reader.ReadLine()) != null) // 逐行读取文件内容
                    {
                        txtContent.Add(line); // 输出每行内容到控制台
                    }
                }
            }
            return txtContent;
        }
        /// <summary>
        /// 逐行读取文件,返回数组
        /// </summary>
        /// <param name="pathAName"></param>
        /// <returns></returns>
        public static string[] ReadTXT_ReadAllLines(string pathAName)
        {
            string[] txtContent = null;
            txtContent = System.IO.File.ReadAllLines(pathAName, Encoding.UTF8);
            return txtContent;
        }
        /// <summary>
        /// 读取,返回字符串
        /// </summary>
        /// <param name="pathAName"></param>
        /// <returns></returns>
        public static string ReadTXT_ReadAllText(string pathAName)
        {
            string txtContent = null;
            txtContent = System.IO.File.ReadAllText(pathAName, Encoding.UTF8);
            return txtContent;
        }
        /// <summary>
        /// 读取,返回枚举类型
        /// 高效地逐行读取大型文本文件的最佳方法
        /// </summary>
        /// <param name="pathAName"></param>
        /// <returns></returns>
        public static string ReadTXT_ReadLines(string pathAName)
        {
            IEnumerable<string> line = System.IO.File.ReadLines(pathAName, Encoding.UTF8);
            return String.Join(Environment.NewLine, line);
        }
        #endregion
    }
}