Question

this is my list

public string state { get; set; }
public string city { get; set; }
public Point p1 { get; set; }
public Point p2 { get; set; }
public List<Explorer> line = new List<Explorer>();
public List<Explorer> rectangle = new List<Explorer>();
public List<Explorer> ellipse = new List<Explorer>();

this is my adding elements to list code

line.Add(new Explorer
            {
                state = "AAAA",
                city = "BBB",
                p1 = start,
                p2 = end
            });

relevant to the values of state and city i need to find the points of their location .

Answer 1

You can use LINQ to filter your list/retrieve the item you want:

using Where

line.Where(e => e.state == "AAAA" && e.city == "BBB")

using Single/SingleOrDefault/First/FirstOrDefault

line.SingleOrDefault(e => e.state == "AAAA" && e.city == "BBB")

If you are only interested in the points, you can use a Select projection

var points = line.Where(e => e.state == "AAAA" && e.city == "BBB")
                    .Select(e=>Tuple.Create(e.p1, e.p2))
                    .Single();