Question

I’m trying to create a simple application that does a HTTP
request/response on a button click. Here’s the entire code which I got
from a reference book:

using System.Collections.Generic;   
using System.ComponentModel;  
using System.Data;  
using System.Drawing;  
using System.Text;  
using System.Windows.Forms;  
using System.IO;  
using System.Net;  

namespace emulator2
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        public void button1_Click(object sender, EventArgs e)
        {
            Uri l_Uri = new Uri("http://www.testing.com");
            HttpWebRequest l_WebReq = (HttpWebRequest)WebRequest.Create(l_Uri);
            HttpWebResponse l_WebResponse =
            (HttpWebResponse)l_WebReq.GetResponse();
            Stream l_responseStream = l_WebResponse.GetResponseStream();
            StreamReader l_SReader = new StreamReader(l_responseStream);
            string resultstring = l_SReader.ReadToEnd();
            Console.WriteLine(resultstring);
        }
    }
}

The thing that puzzles me is that when I shift the entire chunk of code
to a Windows Application, it works fine. But when I use it on a Device
Application, it just throws me an error. Here are the details of the
error:

System.Net.WebException was unhandled Message=”Could not establish
connection to network.” StackTrace: at
System.Net.HttpWebRequest.finishGetResponse() at
System.Net.HttpWebRequest.GetResponse() at
emulator2.Form1.button1_Click() at
System.Windows.Forms.Control.OnClick() at
System.Windows.Forms.Button.OnClick() at
System.Windows.Forms.ButtonBase.WnProc() at
System.Windows.Forms.Control._InternalWnProc() at
Microsoft.AGL.Forms.EVL.EnterMainLoop() at
System.Windows.Forms.Application.Run() at emulator2.Program.Main()

The error points at this line:

HttpWebResponse l_WebResponse = (HttpWebResponse)l_WebReq.GetResponse();

Does anyone have any idea on how to solve this? I need to get this
solved real quick..so any help given is greatly appreciated! Thanks!

Answer 1

My guess is that the emulator doesn’t have proper network connectivity. It can be a pain (and hit-and-miss in my experience) getting networking up and running on the old Windows Mobile emulators. (It’s easy in Windows Phone 7.)

Load up Internet Explorer and see if that can make a connection to the same URL…

Additionally, you’re not disposing of any of your resources (and if this code is really in a reference book exactly as you wrote it, that’s a significant black mark against the book). For example, you should be disposing of the web response:

using (HttpWebResponse response = ...)
{
}

Likewise I would personally dispose of the response stream and the stream reader, just on general principle. I suspect that when the response is disposed, the stream will be too – but it makes sense to dispose of all streams etc unless you know you need to leave them undisposed.