private void button1_Click(object sender, System.EventArgs e)
{

FileStream fs=new FileStream(@"d:\a.txt",FileMode.OpenOrCreate,FileAccess.Read);
StreamReader r=new StreamReader(fs);
while(r.Peek()>=0)
{
listBox1.Items.Add(r.ReadLine());

}
fs.Close();
r.Close();

}
这样可以读取～～