DataTable dt = new DataTable();
string strConn =....;
using (SqlConnection Conn = new SqlConnection(strConn))
{
string strCmd = "select * from ... ";
SqlDataAdapter da = new SqlDataAdapter(strCmd, Conn);
da.Fill(dt);
}
ArrayList arr = new ArrayList();
foreach(DataRow dr in dt.Rows)
arr.Add(dr[0].ToString());
///arr.Add() 方法