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;