using System;

using System.Linq;

using System.Xml.Linq;

public class Program

{

    public static void Main()

    {

        var text = @"Name-FullName

Age-Age

Street Name-AddressDetail-StreetName

Street Number-AddressDetail-StreetNumber

City Name-AddressDetail-CityName";

        var lines = text.Split(new[] {"\r", "\n", "\r\n"}, 0);

        var xDoc = new XDocument(new XElement("Envelop"));

        foreach (var line in lines)

        {

            var values = line.Split('-');

            var parentNode = xDoc.Root;

            foreach (var value in values.Skip(1))

            {

                var name = value.Replace(" ", "");

                var node = parentNode.Element(name);

                if (node == null)

                {

                    node = new XElement(name);

                    parentNode.Add(node);

                }

                parentNode = node;

            }

            parentNode.Value = values.Last();

        }

        Console.WriteLine(xDoc);

    }

}