文件读写操作

如图，点击选择文件则读取文件路径，读取时将文件内容显示到文本框中，写入时将文本框内容写入文件

 namespace 文件操作
{
 public partial class Form1 : Form
 {
 public Form1()
 {
 InitializeComponent();
 }
/// <summary>
/// 选择文件
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
 private void button1_Click(object sender, EventArgs e)
 {
 OpenFileDialog open =new OpenFileDialog();
 open.Filter ="*.txt|*.txt"; //文件类型
if (open.ShowDialog() == DialogResult.OK)
 {
 textBox1.Text = open.FileName;
 }
 }
/// <summary>
/// 读取文件
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
 private void button2_Click(object sender, EventArgs e)
 {
if (textBox1.Text.Length <0)
 {
return;
 }
 Stream stream =new FileStream(textBox1.Text, FileMode.Open, FileAccess.Read);
 using (StreamReader reader =new StreamReader(stream, Encoding.Default))
 {
 string pp ="";
while (reader.Peek() >-1)
 {
 pp += reader.ReadLine();
 }
 richTextBox1.Text = pp;

 }
 }
/// <summary>
/// 写入文件
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
 private void button3_Click(object sender, EventArgs e)
 {
 Stream stream =new FileStream(textBox1.Text, FileMode.Create, FileAccess.Write);
 StreamWriter writer =new StreamWriter(stream, Encoding.Default);
 writer.WriteLine(richTextBox1.Text);

 }
 }
}