how to make a real time graph in visual studio , visual basic window form app

Question

Hello,
I am trying to make a real time line graph with visual basic in visual studio 2022 window form app.
the data of the graph is being pulled from a CSV file. the file updates every 10 sec.
I want to make the graph only portray around 10 data points at a time.
the graph also needs to update when new data point come in, the old data point should not be shown in the graph anymore

https://drive.google.com/file/d/1JwjiqNaGC3Jb3GmQuwSjqY2ekR-TTECc/view?usp=sharing

Above is the link for the CSV file

Answer 1

Hi @Hahhuh456 ,
You can refer to the following code.

Imports System.IO  
Imports System.Windows.Forms.DataVisualization.Charting  
  
Public Class Form1  
    Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click  
        Chart1.Series(0).ChartType = SeriesChartType.Line  
        Timer1.Interval = 1000  
        If Timer1.Enabled = False Then  
            Timer1.Enabled = True  
        Else  
            Timer1.Enabled = False  
        End If  
    End Sub  
  
    Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick  
        Chart1.Series(0).Points.Clear()  
        Dim fName = "C:\Yourfolder\Agriculture_Temp_Log.csv"  
        If File.Exists(fName) = True Then  
            Dim tmpstream As StreamReader = File.OpenText(fName)  
            Dim TextLine() As String = tmpstream.ReadToEnd().Split(Environment.NewLine)  
            For X = TextLine.Length - 12 To TextLine.Length - 2  'reading only the last 10 lines  
                Dim strline = TextLine(X).Split(",")  
                Chart1.Series(0).Points.AddXY(strline(1), CDbl(strline(2)))  
            Next  
            tmpstream.Close()  
        Else  
            MsgBox("file doesn't exist")  
        End If  
    End Sub  
End Class  

Best Regards.
Jiachen Li

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