Question

我在下面的代码中创建了一个在listener.GetContext（）上等待的HTTPLISTENER。

如何从另一个VB应用程序与此通信？我似乎无法让WebRequest.Create使用我的HTTPLISTENER示例正在使用的URI。来自第二个应用程序的这行代码不起作用：

Dim request As WebRequest = WebRequest.Create(prefixes(0))

以下是代码：

Imports System.Net
Imports System.Globalization

Public Class Form1

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

    Dim prefixes() As String = {"http://*:8080/HttpListener/"}

    ProcessRequests(prefixes)

End Sub

Private Sub ProcessRequests(ByVal prefixes() As String)
    If Not System.Net.HttpListener.IsSupported Then
        Console.WriteLine( _
            "Windows XP SP2, Server 2003, or higher is required to " & _
            "use the HttpListener class.")
        Exit Sub
    End If

    ' URI prefixes are required,
    If prefixes Is Nothing OrElse prefixes.Length = 0 Then
        Throw New ArgumentException("prefixes")
    End If

    ' Create a listener and add the prefixes.
    Dim listener As System.Net.HttpListener = _
        New System.Net.HttpListener()
    For Each s As String In prefixes
        listener.Prefixes.Add(s)
    Next

    Try
        ' Start the listener to begin listening for requests.
        listener.Start()
        Console.WriteLine("Listening...")

        ' Set the number of requests this application will handle.
        Dim numRequestsToBeHandled As Integer = 10

        For i As Integer = 0 To numRequestsToBeHandled
            Dim response As HttpListenerResponse = Nothing
            Try
                ' Note: GetContext blocks while waiting for a request. 
                Dim context As HttpListenerContext = listener.GetContext()

                ' Create the response.
                response = context.Response
                Dim responseString As String = _
                    "<HTML><BODY>The time is currently " & _
                    DateTime.Now.ToString( _
                    DateTimeFormatInfo.CurrentInfo) & _
                    "</BODY></HTML>"
                Dim buffer() As Byte = _
                    System.Text.Encoding.UTF8.GetBytes(responseString)
                response.ContentLength64 = buffer.Length
                Dim output As System.IO.Stream = response.OutputStream
                output.Write(buffer, 0, buffer.Length)

            Catch ex As HttpListenerException
                Console.WriteLine(ex.Message)
            Finally
                If response IsNot Nothing Then
                    response.Close()
                End If
            End Try
        Next
    Catch ex As HttpListenerException
        Console.WriteLine(ex.Message)
    Finally
        ' Stop listening for requests.
        listener.Close()
        Console.WriteLine("Done Listening...")
    End Try
End Sub

End Class

Answer 1

验证HttpListener实际上正在侦听的最简单方法是导航到您正在使用浏览器监听的URL。如果找不到它，您将收到404错误。

确认侦听器正在运行后，请尝试使用WebClient在代码中与其进行通信。 WebClient的界面比HttpWebRequest简单得多，并且可以为您提供从流中读取和写入的功能。

string result = WebClient.DownloadString("http://google.com");
Console.WriteLine(result);

如何与我创建的HTTPLISTENER进行通信？

1 个答案: