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首页 - 经验之谈 - 用Visual Basic6.0编写客户服务器程序
发表评论(0)作者:冯 勇, 平台:VB6.0+Win98, 阅读:9528, 日期:2000-09-23
用Visual Basic6.0编写客户服务器程序

冯  勇

Visual Basic6.0提供了Winsock控件,支持网络上两台计算机之间的通信。利用它,编程人员可以毫不费力地编写出TCP/IP客户/服务器程序。以下是用Visual Basic6.0的Winsock控件编写的网络聊天程序的实例。

一.客户程序的实现方法:

1.客户程序设置RemoteHost(远程主机)属性,指定运行服务器的主机名。

2.通过设置RemotePort属性,指定服务器程序的侦听端口。

3.客户程序使用Connect方法向服务器发送连接请求。

4.服务器若空闲,则接受客户的请求,客户程序发生Connect事件,然后可以用SendData方法发送数据。

5.客户程序收到数据时,产生DataArrival事件,在该事件中可以用GetData方法接收数据。

6.如果客户收到Close事件,用Close方法关闭连接。

以下是客户程序的编写过程:

1.   新建一个工程文件,在窗体中加上一个文本框Name为txtRecive,设置 MultiLine属性为True。设置ScrollBars属性为3-Both。

2.   加一标签,Caption为“您的大名:”,后面加一文本框Name为ClientName。

3.   加一标签,Caption为“您的性别:”,后面接一组合框Name为“xingbie“。组合框中加两个OptionButton,分别为Option1,Caption为“男”,Value为True,Option2,Caption为“女”。

4.   加文本框txtSent,设置MultiLine属性为True。

5.   加命令按钮cmdSent,Caption为“发送”, 再加一命令按钮cmdConnect,Caption为“连接”。

6.   加Winsock控件,Name为sckClient。

下面是客户程序的源代码:

Dim messIndex As Integer

Dim firsttime As Boolean

Dim recNumber As Integer

Dim strData As String

  Private Sub cmdConnect_Click()

    On Error GoTo MyError

    sckClient.Connect

    Exit Sub

MyError:

    MsgBox "连接服务器出错!", vbOKOnly, "系统提示"

    Exit Sub

End Sub

  

Private Sub cmdSent_Click()

    Dim name As String

    If txtSent.Text = "" Then

        MsgBox "您想要说什么?", vbOKOnly, "系统提示"

        Exit Sub

    End If

    If Option1.Value = True Then

        name = clientname.Text + "先生: "

    Else

        name = clientname.Text + "小姐: "

    End If

    sckClient.SendData name + txtSent.Text

End Sub

  

Private Sub Form_Load()

    sckClient.RemoteHost = "fdd"   注释:可以更改为你运行服务器的主机名

    sckClient.RemotePort = 8888

    cmdSent.Enabled = False

    messIndex = -1

    firsttime = True

    recNumber = 0

End Sub

  

Private Sub sckClient_Close()

    MsgBox "您使用的名字已经注册或服务器已关闭,请重新连接。"

    End

End Sub

  

Private Sub sckClient_Connect()

    Dim name As String

    MsgBox "连接服务器成功!", vbOKOnly, "系统提示"

    cmdConnect.Enabled = False

    cmdSent.Enabled = True

    If firsttime = True Then

        If Option1.Value = True Then

            name = clientname.Text + "先生"

        Else

            name = clientname.Text + "小姐"

        End If

        sckClient.SendData name

        firsttime = False

        End If

    clientname.Enabled = False

    If Option1.Value = True Then

        Option2.Enabled = False

        Option1.Enabled = False

    Else

        Option1.Enabled = False

        Option2.Enabled = False

    End If

End Sub

  

Private Sub sckClient_DataArrival(ByVal bytesTotal As Long)

    sckClient.GetData strData

    txtRecive.Text = txtRecive.Text & strData & vbCrLf

    txtRecive.SelStart = Len(txtRecive.Text)

End Sub

  

Private Sub sckClient_Error(ByVal Number As Integer, _

    Description As String, ByVal Scode As Long, _

    ByVal Source As String, ByVal HelpFile As String, _

    ByVal HelpContext As Long, CancelDisplay As Boolean)

    sckClient.Close

    cmdConnect.Enabled = True

    cmdSent.Enabled = False

End Sub

  二.服务器程序的实现方法:

1.   设置LocalPort属性,作为侦听端口。该值是一个整型值,但必须是其他TCP/IP程序没有使用过的值。

2.   使用Listen方法进入侦听状态,等待客户程序发出连接请求。

3.   收到客户的连接请求,服务器发生ConnectRequest事件,得到RequestID。

4.   服务器程序用Accept方法接受客户的连接请求。然后可以用SendData方法发送数据。

5.   服务器接受到数据时,发生DataArrival事件,在该事件中可以用GetData的方法接收数据。

6.   如果接收到Close事件,则用Close方法关闭TCP/IP连接。

以下是服务器程序的编写过程:

1. 新建一个工程文件,在窗体中加上一个文本框Name为txtRecive,设置  MultiLine属性为True。设置ScrollBars属性为3-Both。

2. 加一标签,Caption为“连接数”,后面接一个标签,Name为number,Caption为0,设置Appearance为1-3D,BorderStyle为1-Fixed Single。

3. 加一命令按钮,Name为clearmess,Caption为“清除消息”。

4. 加三个WinSock控件,Name分别为sckServer,sckBusy,sckListen。

下面是服务器程序的源代码:

Private MaxNumber As Integer

Dim curnumber As Integer

Dim chatname(50) As String

Dim firstmess(50) As Boolean

  

Private Sub clearmess_Click()

    txtRecive.Text = ""

End Sub

  

Private Sub Form_Load()

    MaxNumber = 50

    curnumber = 0

    For l = 0 To MaxNumber

        firstmess(l) = True

    Next l

    For i = 1 To MaxNumber - 1

        Load sckServer(i)

    Next i

    sckListen.LocalPort = 8888

    sckListen.Listen

End Sub

  

Private Sub sckBusy_Close()

    sckBusy.Close

End Sub

  

Private Sub sckBusy_DataArrival(ByVal bytesTotal As Long)

    sckBusy.SendData "服务器忙,请稍后再连接!"

    DoEvents

End Sub

  

Private Sub sckListen_ConnectionRequest(ByVal requestID As Long)

    Dim i As Integer

    For i = 0 To MaxNumber - 1

    If sckServer(i).State = 0 Then

        Exit For

    End If

    Next i

    If sckServer(i).State = 0 Then

        sckServer(i).Accept requestID

        sckServer(i).SendData "欢迎您参加入网络聊天!"

        curnumber = curnumber + 1

        number.Caption = curnumber

        Exit Sub

    End If

    sckBusy.Close

    sckBusy.Accept requestID

End Sub

  

Private Sub sckListen_Error(ByVal number As Integer, _

    Description As String, ByVal Scode As Long, _

    ByVal Source As String, ByVal HelpFile As String, _

    ByVal HelpContext As Long, CancelDisplay As Boolean)

    sckListen.Close

    sckListen.LocalPort = 8888

    sckListen.Listen

End Sub

  

Private Sub sckServer_Close(Index As Integer)

    Dim j As Integer

    sckServer(Index).Close

    firstmess(Index) = True

    For j = 0 To MaxNumber - 1

        If sckServer(j).State = 7 Then

            sckServer(j).SendData chatname(Index) + "退出网络聊天"

            DoEvents

        End If

    Next j

    curnumber = curnumber - 1

    number.Caption = curnumber

End Sub

  

Private Sub sckServer_DataArrival(Index As Integer, ByVal bytesTotal As Long)

    Dim strData As String

    Dim i As Integer

    sckServer(Index).GetData strData

    If firstmess(Index) = True Then

        chatname(Index) = strData

        firstmess(Index) = False

        For m = 0 To 49

            If (Index <> m) And (chatname(m) = strData) Then

                sckServer(Index).Close

                firstmess(Index) = True

                curnumber = curnumber - 1

                number.Caption = curnumber

                Exit Sub

            End If

        Next m

        strData = strData + "加入网络聊天"

    End If

    For i = 0 To MaxNumber - 1

        If sckServer(i).State = 7 Then

            sckServer(i).SendData strData

            DoEvents

        End If

    Next i

    txtRecive.Text = txtRecive.Text & "Index " & Index & " " & strData + vbCrLf

    txtRecive.SelStart = Len(txtRecive.Text)

End Sub

  

Private Sub sckServer_Error(Index As Integer, ByVal number As Integer, _

    Description As String, ByVal Scode As Long, ByVal Source As String, _

    ByVal HelpFile As String, ByVal HelpContext As Long, _

    CancelDisplay As Boolean)

    sckServer(Index).Close

End Sub