c#读取文本，不能全部读出来？

Question

private void button2_Click(object sender, EventArgs e)
{
string filePath = "";
OpenFileDialog opd = new OpenFileDialog();
if (opd.ShowDialog() == DialogResult.OK)
{
filePath = opd.FileName;
}
StreamReader sr = new StreamReader(filePath,Encoding.Default);
string s = sr.ReadLine();
while (sr.ReadLine()!=null)
{
textBox1.Text+=s + "\r\n";
s = sr.ReadLine();
}
}
创建一个10行的文本，为什么只能读出来奇数行？无法全部读出来，怎么解决？

Answer 1

while (sr.ReadLine()!=null) //这里又读了一行
改如下
string s = sr.ReadLine();
while (s!=null)
{
textBox1.Text+=s + "\r\n";
s = sr.ReadLine();
}