界面如上面 @H_404_2@
VB.NET 串口异步访问@H_404_2@
所示，新的程序如下。
Imports System
Imports System.Collections.Generic
Imports System.ComponentModel
Imports System.Data
Imports System.Drawing
Imports System.Linq
Imports System.Text
Imports System.IO.Ports
Imports System.Threading
Imports System.Text.RegularExpressions
Public Class Form1
WithEvents Comm As SerialPort = New SerialPort
Private Builder As StringBuilder = New StringBuilder '避免在事件处理方法中反复的创建，所以定义到外面
Private ReceiveCount As Long = 0 '接收计数
Private SendCount As Long = 0 '发送计数
Private Listening As Boolean = False '是否没有执行完invoke相关操作
Private Closingg As Boolean = False '是否正在关闭串口，执行Application.DoEvents，并阻止再次invoke
Public Delegate Sub UpdateData(ByVal mByte() As Byte)
Public Sub ShowData(ByVal mByte() As Byte)
Console.WriteLine(mByte)
ReceiveCount += mByte.Length '统计字节总数
Builder.Clear() '清除字符串构造器的内容
Console.WriteLine("Main1() invoke on thread{0}.",Thread.CurrentThread.ManagedThreadId)
If CheckBoxHex.Checked Then
For Each b As Byte In mByte
Builder.Append(b.ToString("X2") + " ")
Next
Else
Builder.Append(Encoding.ASCII.GetString(mByte))
End If
TxtGet.AppendText(Builder.ToString)
labelGetCount.Text = "Get:" + ReceiveCount.ToString
End Sub
'**************************************************************
'委派子程序
'处理上述通信端口的接收事件
'由于欲将数据显示到接收文字框中，因此必须检查是否由另外的Thread
'所呼叫的，若是，则必须先建立委派对象
'Invoke用于在拥有控制项基础视窗控制代码的执行绪上执行委派
'**************************************************************
Private Sub DisplayText(ByVal comData() As Byte)
'如果呼叫txtReceive的是另外的执行绪，传回True
Try
If Me.TxtGet.Invokerequired Then
'利用委派型别建立委派对象，并指定委派的函数
Dim d As New UpdateData(AddressOf ShowData)
'用大括号 {} 括住初始值，藉以初始化阵列的值。
Me.Invoke(d,New Object() {comData}) '以指定的引数清单叫用函数
Else '相同的执行绪
ShowData(comData) '将收到的数据填入接收文字框中
End If
Catch ex As Exception
MsgBox(ex.ToString)
Finally
End Try
End Sub
Private Sub Form1_Load(sender As System.Object,e As System.EventArgs) Handles MyBase.Load
'初始化下拉串口名称列表框
Dim Ports() As String = SerialPort.GetPortNames
Array.Sort(Ports)
ComboPortName.Items.AddRange(Ports)
ComboPortName.SelectedIndex = IIf(ComboPortName.Items.Count > 0,-1)
ComboBaudrate.SelectedIndex = ComboBaudrate.Items.IndexOf("9600")
'初始化Serialport对象
Comm.NewLine = vbCrLf
Comm.RtsEnable = True
'AddHandler Obj.Ev_Event,AddressOf EventHandler
'RemoveHandler Obj.Ev_Event,AddressOf EventHandler
'AddHandler Comm.DataReceived,AddressOf Comm_DataReceived
BtnXReset.PerformClick()
End Sub
Private Sub Comm_DataReceived(sender As Object,e As System.IO.Ports.SerialDataReceivedEventArgs) Handles Comm.DataReceived
If Closingg Then Return '如果正在关闭，忽略操作，直接返回，尽快的完成串口监听线程的一次循环
Try
Listening = True '设置标记，说明我已经开始处理数据，一会儿要使用系统UI的。
Dim n As Long = Comm.BytesToRead '先记录下来，避免某种原因，人为的原因，操作几次之间时间长，缓存不一致
Dim Buf(n - 1) As Byte '声明一个临时数组存储当前来的串口数据
Comm.Read(Buf,n) '读取缓冲数据
Console.WriteLine("Main0() invoke on thread{0}.",Thread.CurrentThread.ManagedThreadId)
DisplayText(Buf)
'Dim b As UpdateData = AddressOf ShowData
'b(Buf) '同步线程之间传递数据时，必须考虑textBox不在同一线程
Catch ex As Exception
MsgBox(ex.Message)
Finally
Listening = False '我用完了，ui可以关闭串口了。
End Try
End Sub
Private Sub BtnXOpen_Click(sender As System.Object,e As System.EventArgs) Handles BtnXOpen.Click
'根据当前串口对象，来判断操作
If Comm.IsOpen Then
Closingg = True '
While Listening
Application.DoEvents()
End While
'打开时点击，则关闭串口
Comm.Close()
Closingg = False
Else
Comm.PortName = ComboPortName.Text
Comm.BaudRate = Integer.Parse(ComboBaudrate.Text)
Try
Comm.Open()
Catch ex As Exception
'捕获到异常信息，创建一个新的comm对象，之前的不能用了。
Comm = New SerialPort
'现实异常信息给客户。
MessageBox.Show(ex.Message)
End Try
End If
'设置按钮的状态
BtnXOpen.Text = IIf(Comm.IsOpen,"Close","Open")
BtnXOpen.Enabled = Comm.IsOpen
End Sub
'动态的修改获取文本框是否支持自动换行。
Private Sub CheckBoxNewLineGet_CheckedChanged(sender As System.Object,e As System.EventArgs) Handles CheckBoxNewLineGet.CheckedChanged
TxtGet.WordWrap = CheckBoxNewLineGet.Checked
End Sub
Private Sub BtnXSend_Click(sender As System.Object,e As System.EventArgs) Handles BtnXSend.Click
Dim n As Integer = 0 '定义一个变量，记录发送了几个字节
If checkBoxHexSend.Checked Then '16进制发送
'我们不管规则了。如果写错了一些，我们允许的，只用正则得到有效的十六进制数
Dim Mc As MatchCollection = Regex.Matches(TxtSend.Text.Trim,"(?i)[/da-f]{2}") '"(?i)[/da-f]{2}"
Dim buf As List(Of Byte) = New List(Of Byte)
'依次添加到列表中
For Each m As Match In Mc
' buf.Add(Byte.Parse(m.Value))
buf.Add(Byte.Parse(m.Value,System.Globalization.NumberStyles.HexNumber))
Next
'转换列表为数组后发送
Comm.Write(buf.ToArray,buf.Count)
n = buf.Count
Else 'ascii编码直接发送
'包含换行符
If checkBoxNewlineSend.Checked Then
Comm.WriteLine(TxtSend.Text)
n = TxtSend.Text.Length + 2
Else
Comm.Write(TxtSend.Text)
n = TxtSend.Text.Length
End If
End If
SendCount += n '累加发送字节数
labelSendCount.Text = "Send:" + SendCount.ToString
End Sub
Private Sub BtnXReset_Click(sender As System.Object,e As System.EventArgs) Handles BtnXReset.Click
'复位接受和发送的字节数计数器并更新界面。
SendCount = 0
ReceiveCount = 0
labelGetCount.Text = "Get:0"
labelSendCount.Text = "Send:0"
Builder.Clear()
End Sub
Private Sub BtxClear_Click(sender As System.Object,e As System.EventArgs) Handles BtxClear.Click
TxtGet.Text = ""
Builder.Clear()
End Sub
End Class
，程序如下