如何：使用代理发送 HTTP 请求
更新：2007 年 11 月
.NET Compact Framework 支持 Web 服务。此示例提交 HTTP GET 请求（使用或不使用指定代理）。
示例
在下面的代码示例中，单击按钮会提交请求并处理响应。请求使用代理（仅当指定时）并使用 WebException 类处理所有异常。它使用 StreamReader 将 HTML 响应读入字符数组缓冲区。
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();
}
}
编译代码
此示例需要引用下面的命名空间：