C#读写文本文件的范例

        private void button1_Click(object sender, EventArgs e)
        {
            //把文件的内容读入到RICHTEXTBOX中
            FileStream fs = new FileStream("d://1.txt", FileMode.Open, FileAccess.Read);
            StreamReader m_streamReader = new StreamReader(fs);

            //使用StreamReader类来读取文件
            m_streamReader.BaseStream.Seek(0, SeekOrigin.Begin);
            //　从数据流中读取每一行，直到文件的最后一行，并在richTextBox1中显示出内容
　　        this.richTextBox1.Text = "";
            string strLine = m_streamReader.ReadLine();
            while (strLine != null)
            {
                this.richTextBox1.Text += strLine + "/n";
                strLine = m_streamReader.ReadLine();
            }
            //关闭此StreamReader对象
            m_streamReader.Close();
        }

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        private void button2_Click(object sender, EventArgs e)
        {
            FileStream fs = new FileStream("d://1.txt", FileMode.OpenOrCreate, FileAccess.Write);
            StreamWriter m_streamWriter = new StreamWriter(fs);
            //m_streamWriter.Flush();
            //使用StreamWriter来往文件中写入内容
            m_streamWriter.BaseStream.Seek(0, SeekOrigin.Begin);
            //把richTextBox1中的内容写入文件
            m_streamWriter.WriteLine (richTextBox1.Text);
            m_streamWriter.Flush();
            //关闭此文件
            m_streamWriter.Close();
        }

 

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        private void button3_Click(object sender, EventArgs e)
        {
            //详解FILE类常用方法说明
            //http://venus.net.blog.163.com/blog/static/244652352007114540673/
           
            //关于字符串前面加@的用法
            //http://apps.hi.baidu.com/share/detail/5632430
           
            //比较精简的读写文件的例子
            //File.ReadAllText或者File.ReadAllLines区别是
            //前者读取所有内容放到一个string中
            //后者放到string数组中
            //前者带回车换行标记，后者不带，
            //不过要带上回车换行标记的话，需要遍历整个数组，
            //用stringbulder进行字符串构造，直接用+的话，时间效率很低

            //第一种读文件方法
            string[] str = File.ReadAllLines(@"D:/1.txt");//用这个方法读

            for (int i = 0; i <= str.Length - 1; i++)
            {
                richTextBox1.Text += str[i].ToString();
            }
            //第二种读文件方法
            string str1 = File.ReadAllText(@"D:/1.txt");//用这个方法读
            richTextBox1.Text += str1;           
            //第一种写文件方法
            File.AppendAllText(@"D:/1.txt",richTextBox1.Text);//用这个方法写入
            //第二种写文件方法
            File.WriteAllText(@"D:/1.txt", richTextBox1.Text);
        }

 

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