VS2010环境下使用VB编写串口助手

1、在Form1的设计模式下添加以下控件：

2、添加好控件之后我们就可以打开Form1.vb进行编程了：

 '使用串口需要引用的命名空间
 Imports System.IO.Ports
 Imports System

 Public Class Form1

     '在设计视图中双击Form1窗体出现的函数，在第一次显示窗体前发生的事件写在这个里面，类似于ViewWillAppear
     Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

         Dim ports As String() = SerialPort.GetPortNames() '必须用命名空间，用SerialPort,获取计算机的有效串口

         Dim port As String

         For Each port In ports
             portnamebox.Items.Add(port) '向combobox中添加项
         Next

         '初始化界面
         baudratebox.Text = baudratebox.Items() '注释和不注释的地方可以替换
         portnamebox.Text = portnamebox.Items()
         'baudratebox.SelectedIndex() = 2
         ' portnamebox.SelectedIndex() = 0
         Serial_Port1() '初始化串口
         Label3.Text = SerialPort1.IsOpen
         statuslabel.Text = "串口未连接"
         statuslabel.ForeColor = Color.Red
         sendbox.Text = ""
         receivebytes.Text = ""
         linecheck.Enabled = True
         timebox.Enabled = True

         '让发送、接收数据按钮不能点击（失能）
         Button1.Enabled = False
         Button2.Enabled = False
         Button3.Enabled = False

     End Sub

     Private Sub Serial_Port1() '设置串口参数
         'SerialPort1.BaudRate = Val(baudratebox.Text) '波特率
         'SerialPort1.PortName = portnamebox.Text '串口名称
         SerialPort1.PortName = portnamebox.SelectedItem
         SerialPort1.BaudRate = Val(baudratebox.SelectedItem)
         SerialPort1.DataBits =  '数据位
         SerialPort1.StopBits = IO.Ports.StopBits.One '停止位
         SerialPort1.Parity = IO.Ports.Parity.None '校验位
     End Sub

     '关闭串口连接
     Private Sub closebtn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles closebtn.Click
         Try
             SerialPort1.Close() '关闭串口

             '让发送、接收数据按钮不能点击（失能）
             Button1.Enabled = False
             Button2.Enabled = False
             Button3.Enabled = False

             Label3.Text = SerialPort1.IsOpen
             If SerialPort1.IsOpen = False Then
                 statuslabel.Text = "串口未连接"
                 statuslabel.ForeColor = Color.Red
                 receivebox.Text = ""
                 receivebytes.Text = ""
             End If
         Catch ex As Exception
             MessageBox.Show(ex.Message)
         End Try
     End Sub

     '打开串口连接
     Private Sub openbtn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles openbtn.Click
         Try
             SerialPort1.Open() '打开串口
             timebox.Enabled = True
             '使能按钮
             Button1.Enabled = True
             Button2.Enabled = True
             Button3.Enabled = True

             Label3.Text = SerialPort1.IsOpen
             If SerialPort1.IsOpen = True Then
                 statuslabel.Text = "串口已连接"
                 statuslabel.ForeColor = Color.Green
             End If
         Catch ex As Exception
             MessageBox.Show(ex.Message)
         End Try
     End Sub

     '手动发送数据
     Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
         send()
     End Sub

     '触发接收事件，接收数据
     Public Sub Sp_DataReceived(ByVal sender As Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles SerialPort1.DataReceived
         Me.Invoke(New EventHandler(AddressOf Sp_Receiving)) '调用接收数据函数
     End Sub

     '接收数据过程
     Private Sub Sp_Receiving(ByVal sender As Object, ByVal e As EventArgs)

         ' Dim strIncoming As Byte
         Dim strIncoming As Integer
         Dim str1() As String
         Dim str2() As String
         Dim bytes() As Byte
         Dim i As Integer
         Try
             Threading.Thread.Sleep() '添加的延时
             ' receivebytes.Text = Str(Val(receivebytes.Text) + SerialPort1.BytesToRead)
             receivebytes.Text = Str(SerialPort1.BytesToRead)

             If SerialPort1.BytesToRead >  Then

                 ReDim bytes(SerialPort1.BytesToRead)
                 'strIncoming = Convert.ToByte(SerialPort1.ReadByte())
                 If receivecheck.Checked = True Then
                     strIncoming = SerialPort1.ReadByte()
                     bytes() = strIncoming
                     For i =  To SerialPort1.BytesToRead
                         strIncoming = SerialPort1.ReadByte() '读取缓冲区中的数据
                         bytes(i) = strIncoming
                     Next
                     ' SerialPort1.Write(sendbox.Text)'发送数据
                     SerialPort1.DiscardInBuffer()
                     str1 = Split(BitConverter.ToString(bytes), "-")

                     ReDim str2(str1.Length - ) '去除str1中最后的字符
                     For i =  To str1.Length -
                         str2(i) = str1(i)
                     Next
                     receivebox.Text = receivebox.Text & Join(str2, " ")
                     'BitConverter.ToString(bytes)
                 Else
                     receivebox.Text = receivebox.Text & SerialPort1.ReadExisting()
                 End If

             End If

         Catch ex As Exception
             MessageBox.Show(ex.Message)
         End Try
     End Sub

     Public Sub send() '发送数据过程
         Dim databyte() As Byte
         Dim str1() As String
         Dim str2 As String
         Dim str3 As String
         Dim i As Integer

         Try
             If sendcheck.Checked = False Then '不按照16进制发送
                 'timecheck.Enabled = True

                 If linecheck.Checked = False Then '判断是否选中分行发送
                     SerialPort1.Write(sendbox.Text)
                 Else
                     SerialPort1.WriteLine(sendbox.Text)
                 End If

             Else '按照16进制发送
                 If InStr(sendbox.Text, " ") Then '判断是否有空格
                     str1 = Split(sendbox.Text)
                     str2 = Join(str1, "")
                 Else
                     str2 = sendbox.Text
                 End If

                 If str2.Length Mod  =  Then '判断字符串字节数是否为偶数
                     ReDim databyte(str2.Length / ) '重新定义数组
                     For i =  To str2.Length /  -
                         databyte(i) = Convert.ToByte(Mid(str2,  * i + , ), ) '两个字符转换为一个16进制字节
                         'databyte(i) = Val(Mid(str2, 2 * i + 1, 2))
                     Next
                     SerialPort1.Write(databyte, , databyte.Length - )
                     sendbytes.Text = Str(Val(sendbytes.Text) + databyte.Length - )
                 Else

                     str3 = Mid(str2, , (str2.Length - )) & "" & Mid(str2, str2.Length)
                     ReDim databyte(str3.Length / )
                     For i =  To str3.Length /  -
                         databyte(i) = Convert.ToByte(Mid(str3,  * i + , ), )
                     Next
                     SerialPort1.Write(databyte, , databyte.Length - )
                     sendbytes.Text = Str(Val(sendbytes.Text) + databyte.Length - )
                 End If
                 'databyte = System.Text.Encoding.Default.GetBytes(sendbox.Text)把每个字符转换成字节

             End If

         Catch ex As Exception
             MessageBox.Show(ex.Message)
         End Try

     End Sub

     '更改串口设置
     Private Sub portnamebox_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles portnamebox.SelectedIndexChanged
         Try
             Serial_Port1()
         Catch ex As Exception
             MessageBox.Show(ex.Message)
         End Try
     End Sub

     '清空发送区数据
     Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
         sendbox.Text = ""
     End Sub

     '清空接收区数据
     Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
         receivebox.Text = ""
         receivebytes.Text = 

     End Sub

     '定时发送数据
     Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
         Timer1.Interval = timebox.Text
         send()
     End Sub

     '选择定时发送的触发事件
     Private Sub timecheck_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles timecheck.CheckedChanged

         If timecheck.Checked = True Then
             If timebox.Text = "" Then
                 MsgBox("时间间隔不能为0")
                 timecheck.Checked = False
             Else
                 send()
                 timebox.Enabled = False
             End If
         Else
             timebox.Enabled = True
         End If
     End Sub

 End Class

然后运行，由于我电脑上没有串口，所以使用usb转串口线，这个线所用的转换芯片是ch340。

安装好驱动之后在计算机管理中查是COM3.

然后把串口的2,3针脚用杜邦线短路，因为这样的话我用电脑发送后又可以用电脑的同一个串口接收数据，方便测试。

测试效果如下：