数据库操作问题：确保列表中最大索引小于列表大小！

Question

using(SqlDataReader reader=cmd.ExecuteReader())
 {
       if(reader.Read())
        {
           //ErrorTimes为数据库表中列名，提示下面一行未处理异常
           int errorTimes = reader.GetInt32(reader.GetOrdinal("ErrorTimes"));
           if(errorTimes>3)
           {
             MessageBox.Show("登录错误次数过多，禁止登录！");
             return;
           }
        }
}
求大神指点，怎么修改！

Answer 1

你先确保 ErrorTimes是否存在

Answer 2

数据库中是存在啊 int型的

Answer 3

保证你的查询语句包含该列 
int errorTimes =(int)reader["ErrorTimes"];//试试

Answer 4

你断点看一下，reader["ErrorTimes"]是神马不就清楚了吗？

Answer 5

数据库中只有一条记录其中ErrorTimes=0；
断点 变量ErrorTimes值也是0

Answer 6

断点后 运行ErrorTimes就是数据库中的值啊

Answer 7

 using(SqlConnection conn=new SqlConnection("Data Source=.\\SQLEXPRESS;AttachDBFilename=|DataDirectory|\\MyDB.mdf;Integrated Security=True;User Instance=True"))
            {
                conn.Open();
                using(SqlCommand cmd=conn.CreateCommand())
                {
                    cmd.CommandText="select count(*) from T_Users where UserName=@UserName";
                    cmd.Parameters.Add(new SqlParameter("UserName",textBox1.Text));
                    using(SqlDataReader reader=cmd.ExecuteReader())
                    {
                        while(reader.Read())
                        {
                            int errorTimes = reader.GetInt32(reader.GetOrdinal("ErrorTimes"));
                            if(errorTimes>3)
                            {
                                MessageBox.Show("登录错误次数过多，禁止登录！");
                                return;
                            }
                            string dbpassword=reader.GetString(reader.GetOrdinal("Password"));
                            if(dbpassword==textBox2.Text)
                            {
                                MessageBox.Show("登录成功！");
                                ResetErrorTimes();//重置登录错误次数
                                 }
                            else
                            {  
                                IncErrorTimes();
                                MessageBox.Show("登录失败！");
                            }
                        }                    }
                }
            }

Answer 8

select count(*) from T_Users where UserName=@UserName
你的SQL语句查询出来就一列，这条SQL语句中没有“ErrorTimes”列，也没有“Password”列啊，在reader里面取值肯定报错。