Question

我是套接字编程的新手。所以，最近我被分配到使用vb.net进行套接字编程的任务，以找出为什么这个程序分配了近20GB的物理内存。但由于我对Socket没有适当的知识，所以我完全被困在里面。我发现BeginReceive()方法和EndReceive()方法作为回调在程序中，当我搜索这些时，我发现了一些EndReceive()应该调用回调的信息。所以，我的问题是：

每次EndReceive()之后是否需要调用BeginReceive()方法来清除缓冲区以便内存分配变得清晰？
如果有人用简单的词语解释BeginReceive()和EndReceive()的真正含义，我真的很感激。

更新：请检查我在项目中找到的以下代码：

Public Sub Receive(ByVal client As Socket)

      Dim state As New StateObject
    state.workSocket = client


    Try
        If m_clientSocket.Connected Then

            client.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0, New AsyncCallback(AddressOf ReceiveCallback), state)
        Else
            Connect()
        End If

    Catch se As SocketException
        logstr = se.Message
        write_log(logstr, "Receive", "Receive")
    End Try
End Sub


 Public Sub ReceiveCallback(ByVal ar As IAsyncResult)


    Dim state As StateObject = CType(ar.AsyncState, StateObject)
    Dim client As Socket = state.workSocket
    Dim receiveData As String = ""
    Dim sendData As String = ""

    Dim bytesRead As Integer = client.EndReceive(ar)

    If bytesRead > 0 Then

        state.sb.Append(System.Text.Encoding.ASCII.GetString(state.buffer, 0, bytesRead))

        client.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0, New AsyncCallback(AddressOf ReceiveCallback), state)      

        receiveData = state.sb.ToString()

        Me.lsBulk.Items.Insert(0, receiveData)
        sendData = getReply(receiveData)
        write_log(Now.ToString & " : " & receiveData & vbCrLf, "bytesRead", "bytesRead")

        Try
            Dim objData As [Object] = sendData
            Dim byData As Byte() = System.Text.Encoding.ASCII.GetBytes(objData.ToString())
            If m_clientSocket IsNot Nothing Then
                m_clientSocket.Send(byData)
            End If

            write_log(Now.ToString & " : " & sendData & vbCrLf, "sendData", "sendData")
        Catch se As SocketException
            logstr = se.Message
            write_log(logstr, "WaitForData", "waitfordata")
        End Try

    Else

        receiveData = state.sb.ToString()


        If receiveData <> "" Then
            write_log(Now.ToString & " : " & receiveData & vbCrLf, "receiveData2", "receiveData2")
        End If


    End If
End Sub

Answer 1

根据文档BeginReceive＆＃34;开始异步接收来自已连接的Socket的数据。＆＃34;。因此，在正常语言中：在继续执行程序的同时开始接收数据。

在EndReceive＆＃34;的文档中，回调方法必须接受BeginConnect方法返回的IAsyncResult作为参数。＆＃34;和＆＃34;获取Socket后，您可以调用EndConnect方法成功完成连接尝试。＆＃34;

并且：＆＃34;必须通过调用EndReceive方法来完成异步BeginReceive操作。通常，该方法由回调委托调用。＆＃34;

是的，您必须致电EndReceive以获取BeginReceive的结果。

另外，作为对第二个问题的回答：＆＃34;要获取接收的数据，请调用AsyncState的{{1}}方法，并提取生成的状态对象中包含的缓冲区。＆＃34;因此结果缓存在IAsyncResult对象中。从那里提取它并摆脱对象让GC收集它。

来源：BeginReceive，EndReceive，IAsyncResult。

什么是BeginReceive（Byte（），Int32，Int32，SocketFlags，AsyncCallback，Object）和socket中的回调方法？

1 个答案: