mysql-c#为什么老出现无法将QQmanagerDB.Item隐式转换为system.Array

public Array[] GetAll(string sql)
{
Array[] arr = new Array[100];
int i = 0;
try
{
SqlCommand command = new SqlCommand(sql,db.conn);
db.Open();
SqlDataReader reader = command.ExecuteReader();
while (reader.Read())
{
Item it = new Item();
it.ID = Convert.ToInt32(reader["ID"]);
it.Name = (reader["Name"]).ToString();
it.Level = (reader["Level"]).ToString();
it.Email = (reader["Email"]).ToString();
it.days = Convert.ToDouble(reader["days"]);
arr[i] = it;
i++;
}
}

page：

case 1:

                    string sql = "select * from Users";                    Array[] arr = man.GetAll(sql);                    Console.WriteLine("----------------------------------------------------------");                    Console.WriteLine("编号\t昵称\t等级\t天数\t邮箱");                    Console.WriteLine("----------------------------------------------------------");                    foreach (Array item in arr)                    {                        if (item != null)                        {                            Console.WriteLine("{0}\t{1}\t{2}\t{3}\t{4}");                        }                        else                        {                           break;                           }                        Console.WriteLine("----------------------------------------------------------");                    }                    break;