使用VB.NET显示Arduino传感器值

Question

我正在尝试创建一个应用程序来使用VB .NET显示来自Arduino的湿度传感器值。我想在Label1.Text中显示传感器值，但它似乎并不总是显示正确的值。

我也尝试显示值到RichTextBox，它可以显示正确的值。例如，如果读数值为1023，则RichTextBox1中显示的值为1023，但Label1中的值为23或023，或者有时是3.

对此有何帮助？

Private Sub SerialPort1_DataReceived(ByVal sender As System.Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles SerialPort1.DataReceived 
    ReceivedText(SerialPort1.ReadExisting()) 
End Sub 

Private Sub ReceivedText(ByVal [text] As String) 
    If Me.RichTextBox1.InvokeRequired Then 
     Dim x As New SetTextCallBack(AddressOf ReceivedText) 
     Me.Invoke(x, New Object() {(text)}) 
    Else 
     RichTextBox1.Text &= [text] 
     Label1.Text = Val([text]) 
    End If 
End Sub 

Answer 1

你为什么要使用Val设置你Label1的Text财产？

Val将包含在字符串中的数字作为数值返回，并停止在第一个字符处读取字符串，而无法将其识别为数字的一部分。

E.g：

Dim valResult As Double 
' The following line of code sets valResult to 2457. 
valResult = Val("2457") 
' The following line of code sets valResult to 2457. 
valResult = Val(" 2 45 7") 
' The following line of code sets valResult to 24. 
valResult = Val("24 and 57") 

如果您收到的读值作为字符串...

Label1.Text = text 

Answer 2

所以我发现我的问题的解决方案。我使用ReadLine（）而不是ReadExisting（）并进行了一些字符串操作。

Private Sub SerialPort1_DataReceived(ByVal sender As System.Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles SerialPort1.DataReceived 
    readbuffer = SerialPort1.ReadLine() 
    Me.Invoke(New EventHandler(AddressOf ReceivedText)) 
End Sub 

Public Sub ReceivedText(ByVal sender As Object, ByVal e As System.EventArgs) 
    Dim read As Decimal 
    read = readbuffer.Replace(vbCr, "").Replace(vbLf, "") 
    Label1.Text = read 
End Sub 

。