I suggest make use of Linq. You may use the following code for your reference
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace ConsoleApplication1
{
public class Point
{
public Double Lat { get; set; }
public Double Lng { get; set; }
}
class Program
{
static void Main(string[] args)
{
List<Point> lstPoints = new List<Point>
{
new Point(){Lat=35.7159323908571, Lng=51.6639151177448},
new Point(){Lat=35.8288428540831, Lng=51.5313353924282},
new Point(){Lat=35.8210003633366, Lng=51.2716503558998}
};
Double MaxLat = lstPoints.OrderByDescending(x => x.Lat).First().Lat;
Double MinLat = lstPoints.OrderByDescending(x => x.Lat).Last().Lat;
Double MaxLng = lstPoints.OrderByDescending(x => x.Lng).First().Lng;
Double MinLng = lstPoints.OrderByDescending(x => x.Lng).Last().Lng;
Console.WriteLine("Max Lat:{0},Min Lat{1}", MaxLat, MinLat);
Console.WriteLine("Max Lng:{0},Min Lng:{1}", MaxLng, MinLng);
Console.ReadLine();
}
}
}