นำค่า sql max มาแปลงเป็นค่า int ไช้ datareader ครับ

sql="SELECT MAX(id) AS MAXID FROM [table]"
con.open
cm = new sqlcommand(sql,con.cn)
rs = cm.executereader
rs.read
if rs("MAXID") is DBNULL.Value then 'ถ้าไม่พบค่าใดๆ 
masbox("ไม่พบค่าครับ")
else
run=rs("MAXID")
end if
con.close

SqlCommand command = new SqlCommand();
command.CommandText = "select max(id) from receives";
int maxId = Convert.ToInt32(command.ExecuteScalar());

            string connString = @"Data Source=Sever;Initial Catalog=DB;User ID=sa;Password=1234";
            SqlConnection conn = new SqlConnection(connString);
            conn.Open();
            SqlCommand cmd = new SqlCommand("select max(id) from receives", conn);
            int maxId = Convert.ToInt32(cmd.ExecuteScalar());