Question

我正在尝试向Snom PA1铃声发送网络请求。铃声在一天中定期响起，但偶尔也会试图接触铃声。这样会很好，但是在这种情况发生几次之后，Web请求就会完全停止发送。子仍然运行，但没有响铃。此外，在调试时，webrequest会抛出一个未被catch处理的webexception，即使它包含在try / catch中。

有人知道为什么网页请求会在失败后停止工作吗？

Private Sub ringIPBell(ByVal params() As Object, Optional ByVal secondattempt As Boolean = False)

    Dim IPaddress As String = params(0)
    Dim ringSeconds As Double = params(1)
    Dim wr As Net.HttpWebRequest

    If ringSeconds = 2 Then
        wr = Net.HttpWebRequest.Create("http://" & IPaddress & "/line_login.htm?l=2")
    Else
        wr = Net.HttpWebRequest.Create("http://" & IPaddress & "/line_login.htm?l=1")
    End If
    wr.Method = "post"
    wr.CachePolicy = New System.Net.Cache.RequestCachePolicy(System.Net.Cache.RequestCacheLevel.NoCacheNoStore) 'added Oct2010
    wr.Credentials = New Net.NetworkCredential("correctName", "correctPassword")

    Dim postdata As String = "PLAY_RINGER:1=Play Ringer"

    wr.ContentLength = postdata.Length + 2
    Dim requestStream As IO.Stream, strmwrit As IO.StreamWriter
    Try

        requestStream = wr.GetRequestStream()
        strmwrit = New IO.StreamWriter(requestStream)
        strmwrit.WriteLine(postdata)
        strmwrit.Close()
        Dim responsestream As New IO.StreamReader(wr.GetResponse.GetResponseStream)


        Catch ex As System.Net.WebException
        If Not secondattempt Then
            ringIPBell(params, True)
        End If
        Dim testvar As String = ex.ToString
    Catch ex As Exception
        Beep()
    End Try

此外，我之前有以下代码响铃，但它只适用于两个铃声之一，即使我可以告诉他们的设置是相同的。

requestStream = wr.GetRequestStream()
strmwrit = New IO.StreamWriter(requestStream)
strmwrit.WriteLine(postdata)
strmwrit.Close()
requestStream.Close()

正如我所说，我打破了responestream系列：

requestStream = wr.GetRequestStream()
            strmwrit = New IO.StreamWriter(requestStream)
            strmwrit.WriteLine(postdata)
            strmwrit.Close()

它打破＆＃34; requestStream = wr.GetRequestStream（）＆＃34;

错误：

＆＃34;类型＆＃39; System.Net.WebException＆＃39;的第一次机会异常发生在System.dll中附加信息：操作已超时＆＃34;

失败后Web请求不会重复，尝试/ catch无法正常工作

0 个答案: