Error in sending the ChannelUri to cloudservice

Question

Hi,
I was implementing an app to Receive pushnotifications.The code is below..
  public MainPage()
            /// Holds the push channel that is created or found.
            HttpNotificationChannel pushChannel;
            // The name of our push channel.
            string channelName = "ToastSampleChannel";
            InitializeComponent();
            // Try to find the push channel.
            pushChannel = HttpNotificationChannel.Find(channelName);
            // If the channel was not found, then create a new connection to the push service.
            if (pushChannel == null)
                pushChannel = new HttpNotificationChannel(channelName);
                // Register for all the events before attempting to open the channel.
                pushChannel.ChannelUriUpdated += new EventHandler<NotificationChannelUriEventArgs>(PushChannel_ChannelUriUpdated);
                pushChannel.ErrorOccurred += new EventHandler<NotificationChannelErrorEventArgs>(PushChannel_ErrorOccurred);
                // Register for this notification only if you need to receive the notifications while your application is running.
                pushChannel.ShellToastNotificationReceived += new EventHandler<NotificationEventArgs>(PushChannel_ShellToastNotificationReceived);
                pushChannel.Open();
                // Bind this new channel for toast events.
                pushChannel.BindToShellToast();
            else
                // The channel was already open, so just register for all the events.
                pushChannel.ChannelUriUpdated += new EventHandler<NotificationChannelUriEventArgs>(PushChannel_ChannelUriUpdated);
                pushChannel.ErrorOccurred += new EventHandler<NotificationChannelErrorEventArgs>(PushChannel_ErrorOccurred);
                // Register for this notification only if you need to receive the notifications while your application is running.
                pushChannel.ShellToastNotificationReceived += new EventHandler<NotificationEventArgs>(PushChannel_ShellToastNotificationReceived);
                // Display the URI for testing purposes. Normally, the URI would be passed back to your web service at this point.
                System.Diagnostics.Debug.WriteLine(pushChannel.ChannelUri.ToString());
                MessageBox.Show(String.Format("Channel Uri is {0}",
                    pushChannel.ChannelUri.ToString()));
        private void RegisterUriWithService()
            //Hardcode for solution - need to be updated in case the REST WCF service 
            //address change
            string baseUri = "http://localhost:8000/RegirstatorService/Register?uri={0}";
            string theUri = String.Format(baseUri, pushChannel.ChannelUri.ToString());
            WebClient client = new WebClient();
            client.DownloadStringAsync(new Uri(theUri));
        /// <summary>
        /// Event handler for when the push channel Uri is updated.
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        void PushChannel_ChannelUriUpdated(object sender, NotificationChannelUriEventArgs e)
            Dispatcher.BeginInvoke(() =>
                // Display the new URI for testing purposes.   Normally, the URI would be passed back to your web service at this point.
                System.Diagnostics.Debug.WriteLine(e.ChannelUri.ToString());
                MessageBox.Show(String.Format("Channel Uri is {0}",
                    e.ChannelUri.ToString()));
        /// <summary>
        /// Event handler for when a push notification error occurs.
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        void PushChannel_ErrorOccurred(object sender, NotificationChannelErrorEventArgs e)
            // Error handling logic for your particular application would be here.
            Dispatcher.BeginInvoke(() =>
                MessageBox.Show(String.Format("A push notification {0} error occurred.  {1} ({2}) {3}",
                    e.ErrorType, e.Message, e.ErrorCode, e.ErrorAdditionalData))
        /// <summary>
        /// Event handler for when a toast notification arrives while your application is running.  
        /// The toast will not display if your application is running so you must add this
        /// event handler if you want to do something with the toast notification.
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        void PushChannel_ShellToastNotificationReceived(object sender, NotificationEventArgs e)
            StringBuilder message = new StringBuilder();
            string relativeUri = string.Empty;
            message.AppendFormat("Received Toast {0}:\n", DateTime.Now.ToShortTimeString());
            // Parse out the information that was part of the message.
            foreach (string key in e.Collection.Keys)
                message.AppendFormat("{0}: {1}\n", key, e.Collection[key]);
                if (string.Compare(
                    key,
                    "wp:Param",
                    System.Globalization.CultureInfo.InvariantCulture,
                    System.Globalization.CompareOptions.IgnoreCase) == 0)
                    relativeUri = e.Collection[key];
            // Display a dialog of all the fields in the toast.
            Dispatcher.BeginInvoke(() => MessageBox.Show(message.ToString()));
      I was comming across error in RegisterUriwithService().
string theUri = String.Format(baseUri, pushChannel.ChannelUri.ToString()); in this line I was getting an error.
Error :The name 'pushChannel' does not exist in the current context.
In pushChannel.ChannelUri.ToString() only I was getting channel uri.I dont know why error was raising.Can anybody plzz help me with this error.
ManyThanks....

Answer 1

Hi Venikoti,
I am trying to develop an app for sending and receiving notifications for an windows phone application i have seen your code and  you said it was worked but i am facing little problem while i am debugging the code i am getting an error null exception
was unhand led by the user code at the position line 
string v = pushChannel.ChannelUri.ToString();
And source code is below please help me to sort out this issue
    Copyright (c) 2011 Microsoft Corporation.  All rights reserved.
    Use of this sample source code is subject to the terms of the Microsoft license 
    agreement under which you licensed this sample source code and is provided AS-IS.
    If you did not accept the terms of the license agreement, you are not authorized 
    to use this sample source code.  For the terms of the license, please see the 
    license agreement between you and Microsoft.
    To see all Code Samples for Windows Phone, visit http://go.microsoft.com/fwlink/?LinkID=219604 
using System;
using System.Windows;
using Microsoft.Phone.Controls;
using Microsoft.Phone.Notification;
using System.Text;
using System.Net;
namespace sdkToastNotificationCS
    public partial class MainPage : PhoneApplicationPage
        /// <summary>
        /// MainPage constructor
        /// </summary>
        HttpNotificationChannel pushChannel;
        public MainPage()
            /// Holds the push channel that is created or found.
            HttpNotificationChannel pushChannel;
            // The name of our push channel.
            string channelName = "ToastSampleChannel";
            InitializeComponent();
            // Try to find the push channel.
            pushChannel = HttpNotificationChannel.Find(channelName);
            // If the channel was not found, then create a new connection to the push service.
            if (pushChannel == null)
                pushChannel = new HttpNotificationChannel(channelName);
                // Register for all the events before attempting to open the channel.
                pushChannel.ChannelUriUpdated += new EventHandler<NotificationChannelUriEventArgs>(PushChannel_ChannelUriUpdated);
                pushChannel.ErrorOccurred += new EventHandler<NotificationChannelErrorEventArgs>(PushChannel_ErrorOccurred);
                // Register for this notification only if you need to receive the notifications while your application is running.
                pushChannel.ShellToastNotificationReceived += new EventHandler<NotificationEventArgs>(PushChannel_ShellToastNotificationReceived);
                pushChannel.Open();
                // Bind this new channel for toast events.
                pushChannel.BindToShellToast();
            else
                // The channel was already open, so just register for all the events.
                pushChannel.ChannelUriUpdated += new EventHandler<NotificationChannelUriEventArgs>(PushChannel_ChannelUriUpdated);
                pushChannel.ErrorOccurred += new EventHandler<NotificationChannelErrorEventArgs>(PushChannel_ErrorOccurred);
                // Register for this notification only if you need to receive the notifications while your application is running.
                pushChannel.ShellToastNotificationReceived += new EventHandler<NotificationEventArgs>(PushChannel_ShellToastNotificationReceived);
                // Display the URI for testing purposes. Normally, the URI would be passed back to your web service at this point.
                System.Diagnostics.Debug.WriteLine(pushChannel.ChannelUri.ToString());
                MessageBox.Show(String.Format("Channel Uri is {0}",
                    pushChannel.ChannelUri.ToString()));
        /// <summary>
        /// Event handler for when the push channel Uri is updated.
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        void PushChannel_ChannelUriUpdated(object sender, NotificationChannelUriEventArgs e)
            Dispatcher.BeginInvoke(() =>
                RegisterUriWithService();
                // Display the new URI for testing purposes.   Normally, the URI would be passed back to your web service at this point.
                System.Diagnostics.Debug.WriteLine(e.ChannelUri.ToString());
                MessageBox.Show(String.Format("Channel Uri is {0}",
                    e.ChannelUri.ToString()));
        private void RegisterUriWithService()
            string v = pushChannel.ChannelUri.ToString();
            //Hardcode for solution - need to be updated in case the REST WCF service 
            string baseUri = "http://newlifefoundation.co.in/windows/test.php?shareRegId=" + v;
            System.Diagnostics.Debug.WriteLine(baseUri);
            WebClient client = new WebClient();
            client.DownloadStringCompleted += (s, e) =>
                if (null == e.Error)
                    Dispatcher.BeginInvoke(() =>
                        Console.WriteLine("Sucessfull");
                        Console.ReadLine();
                else
                    Dispatcher.BeginInvoke(() =>
                        Console.WriteLine("Not Sucesdful");
                        Console.ReadLine();
            client.DownloadStringAsync(new Uri(baseUri));
        /// <summary>
        /// Event handler for when a push notification error occurs.
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        void PushChannel_ErrorOccurred(object sender, NotificationChannelErrorEventArgs e)
            // Error handling logic for your particular application would be here.
            Dispatcher.BeginInvoke(() =>
                MessageBox.Show(String.Format("A push notification {0} error occurred.  {1} ({2}) {3}",
                    e.ErrorType, e.Message, e.ErrorCode, e.ErrorAdditionalData))
        /// <summary>
        /// Event handler for when a toast notification arrives while your application is running.  
        /// The toast will not display if your application is running so you must add this
        /// event handler if you want to do something with the toast notification.
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        void PushChannel_ShellToastNotificationReceived(object sender, NotificationEventArgs e)
            StringBuilder message = new StringBuilder();
            string relativeUri = string.Empty;
            message.AppendFormat("Received Toast {0}:\n", DateTime.Now.ToShortTimeString());
            // Parse out the information that was part of the message.
            foreach (string key in e.Collection.Keys)
                message.AppendFormat("{0}: {1}\n", key, e.Collection[key]);
                if (string.Compare(
                    key,
                    "wp:Param",
                    System.Globalization.CultureInfo.InvariantCulture,
                    System.Globalization.CompareOptions.IgnoreCase) == 0)
                    relativeUri = e.Collection[key];
            // Display a dialog of all the fields in the toast.
            Dispatcher.BeginInvoke(() => MessageBox.Show(message.ToString()));
        private void buttonNavigate_Click(object sender, RoutedEventArgs e)
            this.NavigationService.Navigate(new Uri("/Page2.xaml?NavigatedFrom=Main Page", UriKind.Relative));
THNAKS A LOT IN ADVANCE PLEASE PLEASE ANY ONE CAN HELP TO GET OUT OF THIS ISSUE
P.PHANENDRA KUMAR