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：
1 ‘使用串口需要引用的命名空间
2 Imports System.IO.Ports
3 Imports System
4
5
6 Public Class Form1
7
8
9
10 ‘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
11 Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
12
13 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
14
15 Dim port As String
16
17 For Each port In ports
18 portnamebox.Items.Add(port) ‘向combobox中添加项
19 Next
20
21 ‘初始化界面
22 baudratebox.Text = baudratebox.Items(2) ‘注释和不注释的地方可以替换
23 portnamebox.Text = portnamebox.Items(0)
24 ‘baudratebox.SelectedIndex() = 2
25 ‘ portnamebox.SelectedIndex() = 0
26 Serial_Port1() ‘初始化串口
27 Label3.Text = SerialPort1.IsOpen
28 statuslabel.Text = "串口未连接"
29 statuslabel.ForeColor = Color.Red
30 sendbox.Text = "123"
31 receivebytes.Text = "0"
32 linecheck.Enabled = True
33 timebox.Enabled = True
34
35 ‘让发送、接收数据按钮不能点击（失能）
36 Button1.Enabled = False
37 Button2.Enabled = False
38 Button3.Enabled = False
39
40
41
42
43 End Sub
44
45
46 Private Sub Serial_Port1() ‘设置串口参数
47 ‘SerialPort1.BaudRate = Val(baudratebox.Text) ‘波特率
48 ‘SerialPort1.PortName = portnamebox.Text ‘串口名称
49 SerialPort1.PortName = portnamebox.SelectedItem
50 SerialPort1.BaudRate = Val(baudratebox.SelectedItem)
51 SerialPort1.DataBits = 8 ‘数据位
52 SerialPort1.StopBits = IO.Ports.StopBits.One ‘停止位
53 SerialPort1.Parity = IO.Ports.Parity.None ‘校验位
54 End Sub
55
56
57 ‘关闭串口连接
58 Private Sub closebtn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles closebtn.Click
59 Try
60 SerialPort1.Close() ‘关闭串口
61
62 ‘让发送、接收数据按钮不能点击（失能）
63 Button1.Enabled = False
64 Button2.Enabled = False
65 Button3.Enabled = False
66
67 Label3.Text = SerialPort1.IsOpen
68 If SerialPort1.IsOpen = False Then
69 statuslabel.Text = "串口未连接"
70 statuslabel.ForeColor = Color.Red
71 receivebox.Text = ""
72 receivebytes.Text = ""
73 End If
74 Catch ex As Exception
75 MessageBox.Show(ex.Message)
76 End Try
77 End Sub
78
79
80 ‘打开串口连接
81 Private Sub openbtn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles openbtn.Click
82 Try
83 SerialPort1.Open() ‘打开串口
84 timebox.Enabled = True
85 ‘使能按钮
86 Button1.Enabled = True
87 Button2.Enabled = True
88 Button3.Enabled = True
89
90
91 Label3.Text = SerialPort1.IsOpen
92 If SerialPort1.IsOpen = True Then
93 statuslabel.Text = "串口已连接"
94 statuslabel.ForeColor = Color.Green
95 End If
96 Catch ex As Exception
97 MessageBox.Show(ex.Message)
98 End Try
99 End Sub
100
101
102
103 ‘手动发送数据
104 Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
105 send()
106 End Sub
107
108
109 ‘触发接收事件，接收数据
110 Public Sub Sp_DataReceived(ByVal sender As Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles SerialPort1.DataReceived
111 Me.Invoke(New EventHandler(AddressOf Sp_Receiving)) ‘调用接收数据函数
112 End Sub
113
114
115
116 ‘接收数据过程
117 Private Sub Sp_Receiving(ByVal sender As Object, ByVal e As EventArgs)
118
119 ‘ Dim strIncoming As Byte
120 Dim strIncoming As Integer
121 Dim str1() As String
122 Dim str2() As String
123 Dim bytes() As Byte
124 Dim i As Integer
125 Try
126 Threading.Thread.Sleep(100) ‘添加的延时
127 ‘ receivebytes.Text = Str(Val(receivebytes.Text) + SerialPort1.BytesToRead)
128 receivebytes.Text = Str(SerialPort1.BytesToRead)
129
130 If SerialPort1.BytesToRead > 0 Then
131
132 ReDim bytes(SerialPort1.BytesToRead)
133 ‘strIncoming = Convert.ToByte(SerialPort1.ReadByte())
134 If receivecheck.Checked = True Then
135 strIncoming = SerialPort1.ReadByte()
136 bytes(0) = strIncoming
137 For i = 1 To SerialPort1.BytesToRead
138 strIncoming = SerialPort1.ReadByte() ‘读取缓冲区中的数据
139 bytes(i) = strIncoming
140 Next
141 ‘ SerialPort1.Write(sendbox.Text)‘发送数据
142 SerialPort1.DiscardInBuffer()
143 str1 = Split(BitConverter.ToString(bytes), "-")
144
145 ReDim str2(str1.Length - 1) ‘去除str1中最后的字符
146 For i = 0 To str1.Length - 2
147 str2(i) = str1(i)
148 Next
149 receivebox.Text = receivebox.Text & Join(str2, " ")
150 ‘BitConverter.ToString(bytes)
151 Else
152 receivebox.Text = receivebox.Text & SerialPort1.ReadExisting()
153 End If
154
155 End If
156
157 Catch ex As Exception
158 MessageBox.Show(ex.Message)
159 End Try
160 End Sub
161
162 Public Sub send() ‘发送数据过程
163 Dim databyte() As Byte
164 Dim str1() As String
165 Dim str2 As String
166 Dim str3 As String
167 Dim i As Integer
168
169 Try
170 If sendcheck.Checked = False Then ‘不按照16进制发送
171 ‘timecheck.Enabled = True
172
173 If linecheck.Checked = False Then ‘判断是否选中分行发送
174 SerialPort1.Write(sendbox.Text)
175 Else
176 SerialPort1.WriteLine(sendbox.Text)
177 End If
178
179 Else ‘按照16进制发送
180 If InStr(sendbox.Text, " ") Then ‘判断是否有空格
181 str1 = Split(sendbox.Text)
182 str2 = Join(str1, "")
183 Else
184 str2 = sendbox.Text
185 End If
186
187 If str2.Length Mod 2 = 0 Then ‘判断字符串字节数是否为偶数
188 ReDim databyte(str2.Length / 2) ‘重新定义数组
189 For i = 0 To str2.Length / 2 - 1
190 databyte(i) = Convert.ToByte(Mid(str2, 2 * i + 1, 2), 16) ‘两个字符转换为一个16进制字节
191 ‘databyte(i) = Val(Mid(str2, 2 * i + 1, 2))
192 Next
193 SerialPort1.Write(databyte, 0, databyte.Length - 1)
194 sendbytes.Text = Str(Val(sendbytes.Text) + databyte.Length - 1)
195 Else
196
197 str3 = Mid(str2, 1, (str2.Length - 1)) & "0" & Mid(str2, str2.Length)
198 ReDim databyte(str3.Length / 2)
199 For i = 0 To str3.Length / 2 - 1
200 databyte(i) = Convert.ToByte(Mid(str3, 2 * i + 1, 2), 16)
201 Next
202 SerialPort1.Write(databyte, 0, databyte.Length - 1)
203 sendbytes.Text = Str(Val(sendbytes.Text) + databyte.Length - 1)
204 End If
205 ‘databyte = System.Text.Encoding.Default.GetBytes(sendbox.Text)把每个字符转换成字节
206
207 End If
208
209 Catch ex As Exception
210 MessageBox.Show(ex.Message)
211 End Try
212
213 End Sub
214
215 ‘更改串口设置
216 Private Sub portnamebox_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles portnamebox.SelectedIndexChanged
217 Try
218 Serial_Port1()
219 Catch ex As Exception
220 MessageBox.Show(ex.Message)
221 End Try
222 End Sub
223
224 ‘清空发送区数据
225 Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
226 sendbox.Text = ""
227 End Sub
228
229 ‘清空接收区数据
230 Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
231 receivebox.Text = ""
232 receivebytes.Text = 0
233
234 End Sub
235
236 ‘定时发送数据
237 Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
238 Timer1.Interval = timebox.Text
239 send()
240 End Sub
241
242 ‘选择定时发送的触发事件
243 Private Sub timecheck_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles timecheck.CheckedChanged
244
245 If timecheck.Checked = True Then
246 If timebox.Text = "" Then
247 MsgBox("时间间隔不能为0")
248 timecheck.Checked = False
249 Else
250 send()
251 timebox.Enabled = False
252 End If
253 Else
254 timebox.Enabled = True
255 End If
256 End Sub
257
258
259
260
261
262
263 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：
时间： 2024-10-03 09:16:42