nullreferenceexception对象引用未设置

Question

您好我在查找错误和修复错误时遇到了问题，但是代码可以在DB中插入值

这将是我的代码，我怀疑它有错误

foreach (string Filename in filename_active)
        {

                string Spath_active = Filename.ToString();
                string Dpath_active = Properties.Settings.Default.DestPath.ToString();
                StreamReader active_Data_reader = new StreamReader(Spath_active);
                active_num_lines = File.ReadLines(Spath_active.ToString()).Count();
                string[] active_emp_data = new string[active_num_lines];
                active_lines = active_num_lines * -1;

                try// block of code that access the Active_emp.csv file 
                {

                    int i;


                    for (i = 0; i < active_num_lines; i++)// this block of code will cycle all of the row
                    {

                        active_emp_data = File.ReadAllLines(Spath_active.ToString());
                        for (int a = 0; a < active_emp_data.Length; a++)// this block of code will cycle all of the column
                        {
                            active_emp_data = active_Data_reader.ReadLine().Split(new char[] { '|' }, StringSplitOptions.RemoveEmptyEntries);
                            My_addpt.SelectCommand = new SqlCommand("SELECT * FROM NGAC_USERINFO WHERE EmployeeNum =@EmployeeNum", conn);
                            My_addpt.SelectCommand.Parameters.Add("@EmployeeNum", SqlDbType.NVarChar).Value = active_emp_data[2].ToString();
                            conn.Open();

                            SqlDataReader My_reader;
                            My_reader = My_addpt.SelectCommand.ExecuteReader();
                            string man_num = active_emp_data[2].ToString();
                            bool z = false;

                            while (My_reader.Read())
                            {
                                if (My_reader["EmployeeNum"].ToString() == man_num.ToString())// this block of code will check is the data is present in the database 
                                {
                                    z = true;
                                }

                            }