Question

C# listview 的listView1.SelectedItems[0]问题

请高手帮忙指点下 此代码第一次选择可以去除istView1.SelectedItems[0].Tag的值`` 之后再点就报异常 高手指点

private void listView1_SelectedIndexChanged(object sender,EventArgs e)
{

textBox1.Text = "";
textBox2.Text = "";
int index = Convert.ToInt32(listView1.SelectedItems[0].Tag);
MessageBox.Show(index.ToString());

//string sql = string.Format("select studentid,loginid,loginpwd from student where studentid={0} ", index);
//SqlDataReader reader = help.Datereader(sql);
//if (reader.Read())
//{
// textBox1.Text = reader["loginid"].ToString();
// textBox2.Text = reader["loginpwd"].ToString();
//}
//reader.Close();
//DBHelper.connection.Close();
}

Answer 1

异常信息发过来呀，不然怎么判断？
到底是空引用异常呀？还是数字转换的异常呀？