文本的读和写

读:TextBox1.Text=File.ReadAllText("d:/b.txt",Encoding.Default); 

写:File.WriteAllText("d:/a.txt", TextBox1.Text, Encoding.Default); 

追加:File.AppendAllText("d:/a.txt", TextBox1.Text, Encoding.Default); 


最简单的方法 写文件 
    StreamWriter sw = new StreamWriter(fileName); 
    sw.Write(textBox1.Text); 
  sw.Close(); 
读文件 
    StreamReader sr = new StreamReader(fileName); 
    textBox1.Text = sw.ReadToEnd(); 
  sr.Close(); 

 //写

                StreamWriter sw = File.AppendText("log_zd.htm");
                string jilu = "http://zhidao.baidu.com/question/" + counter + ".html
";
                sw.WriteLine(jilu);
                sw.Close();
//读

            StreamReader file = new StreamReader("c://标签.txt", Encoding.Default);
            //将文本放到数组中
            string[] sz = new string[counter];
            while ((line = file.ReadLine()) != null)
            {
                counter1++;
                sz[counter1 - 1] = line;
                //Console.WriteLine(line);
            }