.new 讀資料 sample

using System.Data;
using System.Data.SqlClient;

sql = "SELECT * FROM table";
string _connection = ConfigurationManager.ConnectionStrings["cn"].ConnectionString;
SqlConnection conn = new SqlConnection(_connection);
try {
    SqlCommand cmd = new SqlCommand();
    cmd.Connection = conn;
    cmd.CommandText = sql;
    conn.Open();
    SqlDataAdapter sda = new SqlDataAdapter(cmd);
    DataSet ds = new DataSet();
    sda.Fill(ds);
}
catch (Exception) {
    throw;
}
finally {
    conn.Close();
}