How to calculate fare using distance matrix api asp.net c#

public partial class Pickup3 : System.Web.UI.Page

{

string dkm, ds, distance;

string origin, destination;

double conv = 0.62137;

double miles, d2;

string xmlResult = null;

XmlDocument doc = new XmlDocument();

static int Taxicount;

protected void Page_Load(object sender, EventArgs e)

{

if(!IsPostBack)

{

//double dist = Convert.ToDouble(Session["taxi_distance"]);

double veh = Convert.ToDouble(Session["taxi_vehicle"]);

//startvalue2.Text = Session["taxi_origin"].ToString();

//endvalue2.Text = Session["taxi_destination"].ToString();

}

}

protected void Button2_Click1(object sender, EventArgs e)

{

HttpWebRequest request = (HttpWebRequest)WebRequest.Create("http://maps.googleapis.com/maps/api/distancematrix/xml?origins=" + startvalue.Text + "&destinations=" + endvalue.Text + "&mode=Car&language=us-en&sensor=false");

HttpWebResponse response = (HttpWebResponse)request.GetResponse();

StreamReader resStream = new StreamReader(response.GetResponseStream());

xmlResult = resStream.ReadToEnd();

doc.LoadXml(xmlResult);

try

{

if (doc.DocumentElement.SelectSingleNode("/DistanceMatrixResponse/row/element/status").InnerText.ToString().ToUpper() != "OK")

{

//Response.Write("");

return;

}

XmlNodeList xnList = doc.SelectNodes("/DistanceMatrixResponse");

foreach (XmlNode xn in xnList)

{

if (xn["status"].InnerText.ToString() == "OK")

{

dkm = doc.DocumentElement.SelectSingleNode("/DistanceMatrixResponse/row/element/distance/text").InnerText;

ds = dkm.Replace("km", " ");

distance = ds.Trim();

d2 = Convert.ToDouble(distance);

// miles = conv * d2;

origin = xn["origin_address"].InnerText.ToString();

destination = xn["destination_address"].InnerText.ToString();

Session.Add("taxi_origin", origin);

Session.Add("taxi_destination", destination);

// Session.Add("taxi_distance", miles);

Session.Add("shams", "Return Date and Time");

//Session.Add("taxi_cartype", Rdb_CarType.SelectedValue);

//double dist = Convert.ToDouble(Session["taxi_distance"]);

double veh = Convert.ToDouble(Session["taxi_vehicle"]);

//Lbl_Distance.Text = Math.Round(dist, 2).ToString() + " miles";

// Lbl_Fare.Text = Math.Round(dist * 2.5 * veh, 2).ToString();

string a = "1";

Session.Add("BookTaxi", a);

Taxicount++;

Session.Add("TaxiCount", Taxicount.ToString());

if (Session["taxi_oneway"] == "One Way")

{

//Lbl_Distance.Text = Math.Round(dist, 2).ToString() + " miles";

// Lbl_Fare.Text = Math.Round(dist * 2.5 * veh, 2).ToString();

}

Session.Add("totalfare", Lbl_Fare.Text);

//Session.Add("totaldistance", Lbl_Distance.Text);

}

}

}

catch

{

Response.Write("");

return;

}

}

}