using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using

namespace sx
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            for (int i = 1; i <= 3; i++)
            {

                FileStream message = new FileStream("c:\\student.txt", FileMode.Create, FileAccess.Write);
                StreamWriter text = new StreamWriter(message);
                text.WriteLine(textBox1);
                text.WriteLine(textBox2);
                text.WriteLine(textBox3);
                text.Close();
                message.Close();
            }
                MessageBox.Show("保存成功");
           }

        private void button2_Click(object sender, EventArgs e)
        {

            FileStream message = new FileStream("c:\\student.txt", FileMode.Create, FileAccess.Write);
            message.SetLength(0);
            
        }

        private void button3_Click(object sender, EventArgs e)
        {
            Close();
        }
    }
}
如上代码，试了几次for循环，不成功，还请大神指教。谢谢了。

FileStream message = new FileStream("c:\\student.txt", FileMode.Create, FileAccess.Write);
StreamWriter text = new StreamWriter(message);
text.Close();
message.Close();
你把这几句写在循环外面就行了