Question

VB.net串口接收不到数据

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

Dim ports As String() = SerialPort.GetPortNames() Dim port As String
For Each port In ports
portnamebox.Items.Add(port)
Next port
baudratebox.Items.Add("9600")
SerialPort1.BaudRate = Val(baudratebox.Text)
SerialPort1.PortName = portnamebox.Text
SerialPort1.DataBits = 8
SerialPort1.StopBits = IO.Ports.StopBits.One
SerialPort1.Parity = IO.Ports.Parity.None
End Sub
Private Sub connect_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles connect.Click
SerialPort1.Open()
Label8.Text = SerialPort1.IsOpen
If SerialPort1.IsOpen = True Then
statuslabel.Text = "串口已连接"
statuslabel.ForeColor = Color.Green
End If
End Sub
Private Sub senddata_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles senddata.Click
Dim strincoming As String
SerialPort1.Write(senddata.Text, 0, 4)
If SerialPort1.BytesToRead > 0 Then
Threading.Thread.Sleep(100) '添加延时
strincoming = SerialPort1.ReadExisting.ToString '读取缓冲区中的数据
SerialPort1.DiscardInBuffer()
RXbox.Text = strincoming
End If
End Sub
程序如上 senddata为发送数据，RXbox为接收数据框 ，串口已经打开，自己编的程序senddata输入1 接收RXbox里面都是空的 ，请大师指教

Answer 1

这问题LZ在Csdn上发了两帖，已经给了答复！

不知为何又在此处发帖？

Answer 2

单机调试的话，需要短接串口的2、3脚。