Put the analog Value into webserver

Hi everyone..

i am a student from Indonesia, and i have a final project about counting kWh with netduino plus.

before that, i am sorry for my bad english.

in my project, i want to put my analog value in to webserver and i can request from my browser.

so i can see how much energy that i used.

after read a lot of post and complate with my code,

There's an error that my value cant read in current context.

i need your help..

this is my code..

using System;using System.Threading;using Microsoft.SPOT;using System.Net;using System.Net.Sockets;using Microsoft.SPOT.Hardware;using SecretLabs.NETMF.Hardware;using SecretLabs.NETMF.Hardware.Netduino;using Microsoft.SPOT.Net;using System.IO;namespace NetduinoPlusWebServer{    public class Program    {        const string WebFolder = "SDWeb";        private const int MaximumValue = 1023;        private const float AnalogReference = 3.3f;        private static StreamWriter sw;        static AnalogInput voltage;        public static void Main()        {            Listener webServer = new Listener(RequestReceived);                    }        private static void RequestReceived(Request request)        {            const double maxVoltage = 3.3;            const int maxAdcValue = 1023; // 10-bit Resolution (ADC)            var voltagePort = new AnalogInput(Pins.GPIO_PIN_A2);            var currentPort = new AnalogInput(Pins.GPIO_PIN_A0);            sw = new StreamWriter(@"SDfile.csv");//sdcardfilename            OutputPort led = new OutputPort(Pins.ONBOARD_LED, false);            while (true)            {                //Part Sensor VOLTAGE                int rawValue = voltagePort.Read();                double value = rawValue + 114.11;                double volt = value / 2.15;                //Part Sensor CURRENT                int currentvalue = currentPort.Read();                double varus = (currentvalue* maxVoltage) / maxAdcValue;                double icount = currentvalue - 312;                double current = icount / 57.62;                                //Part KWatt                double voltage = volt;                double iconv = current * 1000; //convert to miliampere                double kWh = voltage * iconv / 3600;                Debug.Print("Total kWh=  " + kWh.ToString());                sw.Write(kWh.ToString());                sw.Write("n");                sw.Flush();                sw.Close();                led.Write(!led.Read());// Blink LED to show we're still responsive                Thread.Sleep(500);            }                        request.SendResponse(                "<html>" +                "<header> Analisis Perhitungan Jumlah Daya Pada Kamar Kos</header>" +                "<p> Time (relative to start time): " + DateTime.Now.ToString() + "</p>" +                "<p> Jumlah kWh Anda sebesar: " + kWh + "</p>" +                "</body>" +                "</html>"                );            // Use this for a really basic check that it's working            //request.SendResponse("<html><body><p>Request from " + request.Client.ToString() + " received at " + DateTime.Now.ToString() + "</p><p>Method: " + request.Method + "<br />URL: " + request.URL +"</p></body></html>");            // Send a file        }    }}