Gewusst wie: Senden einer HTTP-Anforderung mit Proxy
Aktualisiert: November 2007
.NET Compact Framework unterstützt Webdienste. In diesem Beispiel wird eine HTTP-GET-Anforderung mit oder ohne einen angegebenen Proxy gesendet.
Beispiel
Im folgenden Codebeispiel werden mit einem Klick auf eine Schaltfläche die Anforderung gesendet und die Antwort verarbeitet. Die Anforderung verwendet nur dann einen Proxy, wenn ein Proxy angegeben ist. Ausnahmen werden mit der WebException-Klasse behandelt. Die Anforderung verwendet einen StreamReader, um die HTML-Antwort in einen Zeichenarraypuffer zu lesen.
Private ReceiveStream As System.IO.Stream
Private sr As System.IO.StreamReader
Private Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
' Get URL and proxy
' from the text boxes.
Dim url As String = txtURL.Text
Dim proxy As String = txtProxy.Text
Try
If Not "".Equals(txtProxy.Text) Then
Dim proxyObject As New WebProxy(proxy, 80)
' Disable proxy use when the host is local.
proxyObject.BypassProxyOnLocal = True
' HTTP requests use this proxy information.
GlobalProxySelection.Select = proxyObject
End If
Dim req As WebRequest = WebRequest.Create(url)
Dim result As WebResponse = req.GetResponse()
ReceiveStream = result.GetResponseStream()
Dim encode As Encoding = System.Text.Encoding.GetEncoding("utf-8")
sr = New StreamReader(ReceiveStream, encode)
' Read the stream into arrays of 30 characters
' to add as items in the list box. Repeat until
' buffer is read.
Dim read(29) As [Char]
Dim count As Integer = sr.Read(read, 0, 30)
While count > 0
Dim str As New String(read, 0, count)
lstResults.Items.Add(str)
count = sr.Read(read, 0, 30)
End While
Catch ex As WebException
Dim message As String = ex.Message
Dim response As HttpWebResponse = CType(ex.Response, HttpWebResponse)
If Nothing Is response Then
Else
message = response.StatusDescription
response.Close()
End If
lstResults.Items.Add(message)
Catch ex As Exception
lstResults.Items.Add(ex.Message)
Finally
ReceiveStream.Close()
sr.Close()
End Try
End Sub
Stream ReceiveStream = null;
StreamReader sr = null;
private void button1_Click(object sender, System.EventArgs e)
{
// Get URL and proxy
// from the text boxes.
string url = txtURL.Text;
string proxy = txtProxy.Text;
try
{
if(!"".Equals(txtProxy.Text))
{
WebProxy proxyObject = new WebProxy(proxy, 80);
// Disable proxy use when the host is local.
proxyObject.BypassProxyOnLocal = true;
// HTTP requests use this proxy information.
GlobalProxySelection.Select = proxyObject;
}
WebRequest req = WebRequest.Create(url);
WebResponse result = req.GetResponse();
ReceiveStream = result.GetResponseStream();
Encoding encode = System.Text.Encoding.GetEncoding("utf-8");
sr = new StreamReader( ReceiveStream, encode );
// Read the stream into arrays of 30 characters
// to add as items in the list box. Repeat until
// buffer is read.
Char[] read = new Char[30];
int count = sr.Read( read, 0, 30 );
while (count > 0)
{
String str = new String(read, 0, count);
lstResults.Items.Add(str);
count = sr.Read(read, 0, 30);
}
}
catch(WebException ex)
{
string message = ex.Message;
HttpWebResponse response = (HttpWebResponse)ex.Response;
if(null != response)
{
message = response.StatusDescription;
response.Close();
}
lstResults.Items.Add(message);
}
catch(Exception ex)
{
lstResults.Items.Add(ex.Message);
}
finally
{
ReceiveStream.Close();
sr.Close();
}
}
Kompilieren des Codes
Für dieses Beispiel sind Verweise auf die folgenden Namespaces erforderlich: