Application à la lecture d’une image


using System.Net;                            // pour WebClient
 using System.Windows.Media.Imaging;          // pour BitmapImage
 .....
 WebClient client = new WebClient();
 client.OpenReadCompleted 
     += new OpenReadCompletedEventHandler(client_OpenReadCompleted);
 client.OpenReadAsync(new Uri("VG2.jpg", UriKind.Relative));
 .....
 void client_OpenReadCompleted(object sender, OpenReadCompletedEventArgs e)
 {
  try
  {
   BitmapImage image = new BitmapImage();
   image.SetSource(e.Result);
   img.Source = image;
  }
  catch (Exception exc)
  {
   .....     // erreur lors de l’accès, avec message d’erreur dans exc.Message       
  }
 }








Imports System.Net                       ' pour WebClient
 Imports System.Windows.Media.Imaging     ' pour BitmapImage
 .....
 Dim client = New WebClient()
 client.OpenReadAsync(New Uri("VG2.jpg", UriKind.Relative), 0)
 AddHandler client.OpenReadCompleted, AddressOf client_OpenReadCompleted
 .....
 Private Sub client_OpenReadCompleted(ByVal sender As Object, _
                                      ByVal e As OpenReadCompletedEventArgs)
  Try
   Dim image As New BitmapImage()
   image.SetSource(e.Result)
   img.Source = image
  Catch exc As Exception
   .....                  ' message d’erreur dans exc.Message
  End Try
 End Sub










Application à la lecture d’un fichier XML


<?xml version="1.0" encoding="utf-8" ?>
  <Artistes>
   <Artiste>
    <Nom>Brel</Nom>
    <AN>1929</AN>
   </Artiste>
   <Artiste>
    <Nom>Brassens</Nom>
    <AN>1921</AN>
   </Artiste>
   <Artiste>
    <Nom>Ferré</Nom>
    <AN>1916</AN>
   </Artiste>
 </Artistes>





 using System.Net;
 .....
 WebClient client = new WebClient();
 client.DownloadStringCompleted
      += new DownloadStringCompletedEventHandler(client_DownloadStringCompleted);
 client.DownloadStringAsync(new Uri("Artistes.xml", UriKind.Relative));
 .....
 void client_DownloadStringCompleted(object sender, 
                                     DownloadStringCompletedEventArgs e)
 {
  try
  {
   string s = e.Result;
   .....                    .. contenu du fichier XML dans s ..
  }
  catch (Exception exc)
  {
   .....
  }
 }




 using System.Xml.Linq;
 .....
 XElement xml = XElement.Parse(s);
 var listeArtistes = from p in xml.Elements("Artiste") select p;
 foreach (var p in listeArtistes)
 {
           .. nom dans p.Element("Nom").Value ..
           .. année de naissance dans p.Element("AN").Value ..
 }










 Imports System.Xml.Linq
 .....
 Dim client = New WebClient()
 client.DownloadStringAsync(New Uri("Artistes.xml", UriKind.Relative), 0)
 AddHandler client.DownloadStringCompleted, _
     AddressOf client_DownloadStringCompleted
 .....
 Private Sub client_DownloadStringCompleted(ByVal sender As Object, _
                         ByVal e As DownloadStringCompletedEventArgs)
  Try
   Dim s As String = e.Result
   Dim xml As XElement = XElement.Parse(s)
   Dim listeArtistes = From p In xml.Elements("Artiste") _
                       Select p
   For Each p In listeArtistes
    .. nom dans p.Element("Nom").Value ..
    .. année de naissance dans p.Element("AN").Value
   Next p
  Catch exc As Exception
   .....
  End Try
 End Sub












Application à un service Web météo


 WebClient client = new WebClient();
 client.DownloadStringCompleted
    += new DownloadStringCompletedEventHandler(client_DownloadStringCompleted);
 string url = "http://www.webServiceX.net/GlobalWeather.asmx/"
              + "GetCitiesByCountry?CountryName=France";
 client.DownloadStringAsync(new Uri(url), 0);
 .....
 List<string> listeVilles;
 void client_DownloadStringCompleted(object sender,
                                     DownloadStringCompletedEventArgs e)
 {
  try
  {
   string s = e.Result;
   s = s.Replace("&lt;", "<");
   s = s.Replace("&gt;", ">");
   XDocument xml = XDocument.Parse(s);
   XNamespace xmlns = "http://www.webserviceX.NET";
   var q = from p in xml.Elements(xmlns + "string")
                        .Elements(xmlns + "NewDataSet")
                        .Elements(xmlns + "Table") 
           select p.Element(xmlns + "City").Value ;
   listeVilles = q.ToList<string>();
  }
  catch (Exception exc)
  {
   .....        // traiter l’erreur
  }
 }








 Imports System.Xml.Linq
 Imports System.Net
 .....
 Dim client = New WebClient()
 client.DownloadStringAsync( _
           New Uri("http://www.webServiceX.net/GlobalWeather.asmx/"
                   & "GetCitiesByCountry?CountryName=France"), 0)
 AddHandler client.DownloadStringCompleted, _
            AddressOf client_DownloadStringCompleted
 .....
 Dim listeVilles As List(Of String)
 Private Sub client_DownloadStringCompleted(ByVal sender As Object, _
                        ByVal e As DownloadStringCompletedEventArgs)
  Try
   Dim s As String = e.Result
   s = s.Replace("&lt;", "<")
   s = s.Replace("&gt;", ">")
   Dim xml As XDocument = XDocument.Parse(s)
   Dim xmlns As XNamespace = "http://www.webserviceX.NET"
   Dim q = From p In xml.Elements(xmlns + "string").Elements(xmlns + "NewDataSet").Elements(xmlns + "Table") _
           Select p.Element(xmlns + "City").Value
   listeVilles = q.ToList()
  Catch exc As Exception
    .....       ' traiter l’erreur
  End Try
 End Sub








 if (xml.Elements(xmlns + "string").First().Value == "")
    s = "Pas de météo pour ce pays";






 <?xml version="1.0" encoding="utf-8" ?>
  <string xmlns="http://www.webserviceX.NET">
   <?xml version="1.0" encoding="utf-16"?>
    <CurrentWeather>
     <Location>Calvi, France (LFKC) 42-32N 008-48E 58M</Location>
     <Time>May 01, 2008 - 01:30 PM EDT / 2008.05.01 1730 UTC</Time>
     <Wind> from the W (260 degrees) at 7 MPH (6 KT) (direction variable):0</Wind>
     <Visibility> greater than 7 mile(s):0</Visibility>
     <Temperature> 66 F (19 C)</Temperature>
     <DewPoint> 30 F (-1 C)</DewPoint>
     <RelativeHumidity> 25%</RelativeHumidity>
     <Pressure> 30.00 in. Hg (1016 hPa)</Pressure>
     <Status>Success</Status>
  </CurrentWeather>
 </string>









 WebClient client = new WebClient();
 client.DownloadStringCompleted
   += new DownloadStringCompletedEventHandler(client_DownloadStringCompleted);
 string url = "http://www.webServiceX.net/GlobalWeather.asmx/"
              + "GetWeather?CityName=Calvi&CountryName=France";
 client.DownloadStringAsync(new Uri(url), 0);







 string s = e.Result;
 s = s.Replace("&lt;", "<");
 s = s.Replace("&gt;", ">");
 s = s.Replace("<?xml version=\"1.0\" encoding=\"utf-16\"?>", "");
 XElement xml = XElement.Parse(s);
 XNamespace ns = "http://www.webserviceX.NET";
 string temp = xml.Elements(ns + "CurrentWeather")
                  .Elements(ns+"Temperature").First().Value;
 // éliminer la valeur Fahrenheit (degrés Celsius entre parenthèses)
 int n1 = temp.IndexOf("(");
 int n2 = temp.IndexOf(")");
 temp = temp.Substring(n1 + 1, n2 - n1-2);


Application au service Web Flickr

string clé = .. votre identifiant Flickr ici ..
 string url = "http://api.flickr.com/services/rest/"
              + "?method=flickr.photos.search&api_key="
              + clé + "&text=" + sCrit;
 WebClient client = new WebClient();
 client.DownloadStringCompleted
    += new DownloadStringCompletedEventHandler(client_DownloadStringCompleted);
 client.DownloadStringAsync(new Uri(url), 0);







 var liste = from p in xml.Element("rsp").Element("photos").Elements("photo")
             select p  ;
 liste = liste.Take(12);
 .. nombre de photos donné par liste.Count(), soit ici 12 ou moins ..
 foreach (var ph in liste)             // on passe en revue les photos
 {
  .. titre d’une photo dans ph.Attribute("title").Value ..
 }




 string sFarm = liste.ElementAt(N).Attribute("farm").Value;
 string sServer = liste.ElementAt(N).Attribute("server").Value;
 string sId = liste.ElementAt(N).Attribute("id").Value;
 string sSecret = liste.ElementAt(N).Attribute("secret").Value;
 string sUrl = "http://farm" + sFarm + ".static.flickr.com/" + sServer 
               + "/" + sId + "_" + sSecret + ".jpg";
 ImageSource imgs = new System.Windows.Media.Imaging.BitmapImage(new Uri(sUrl));
 img.SetValue(Image.SourceProperty, imgs);