Imports System
Imports System.Drawing
Imports System.Drawing.Drawing2D
Imports System.IO

Public Class Form1

    Private Sub Panel1_Paint(ByVal sender As System.Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles Panel1.Paint

        Dim blackPen As New Pen(Color.Red, 3)

        Dim x1 As Single
        Dim y1 As Single
        Dim x2 As Single
        Dim y2 As Single

        Try
            ' Create an instance of StreamReader to read from a file.

            Using sr As StreamReader = New StreamReader("coordinate.txt")
                Dim line() As String
                ' Read and display the lines from the file until the end 
                ' of the file is reached.
                Do
                    line = Split(sr.ReadLine(), ";", -1)

                    x1 = line(0)
                    y1 = line(1)
                    x2 = line(2)
                    y2 = line(3)

                    e.Graphics.DrawLine(blackPen, x1, y1, x2, y2)

                Loop Until line Is Nothing

                sr.Close()

            End Using
        Catch ex As Exception
            ' Let the user know what went wrong.
            Console.WriteLine("The file could not be read:")
            Console.WriteLine(ex.Message)
        End Try
    End Sub

    Private Sub btnRefresh_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnRefresh.Click
        Me.Panel1.Refresh()
    End Sub
    Private Sub ApriFile(ByVal NomeFile As String)
        Dim Testo As String
        Dim FileReader As System.IO.StreamReader
        Try
            FileReader = New System.IO.StreamReader(NomeFile)
            'Legge l'intero file e lo salva nella variabile "Testo".
            Testo = FileReader.ReadToEnd
            FileReader.Close()
            cncCode.Text = Testo
        Catch ex As System.IO.IOException
            MsgBox("Si è verificato un errore durante la lettura dal file: " & ex.Message)
        Finally
            'Libera le risorse allocate con New.
            FileReader = Nothing
        End Try
    End Sub


    Private Sub mnuFileCommand(ByVal sender As Object, ByVal e As System.EventArgs) Handles mnuFileSalva.Click, mnuFileNuovo.Click, mnuFileEsci.Click, mnuFileApri.Click
        Select Case CType(sender, MenuItem).Text
            Case "&Nuovo"
            Case "&Apri..."
                If dlgApri.ShowDialog = DialogResult.OK Then
                    ApriFile(dlgApri.FileName)
                End If
            Case "&Salva..."
                If dlgSalva.ShowDialog = DialogResult.OK Then
                    SalvaFile(dlgSalva.FileName)
                End If
            Case "&Esci"
                Me.Close()
        End Select
    End Sub
    Private Sub SalvaFile(ByVal NomeFile As String)
        Dim FileWriter As System.IO.StreamWriter
        Try
            FileWriter = New System.IO.StreamWriter(NomeFile)
            'Salva il contenuto di "txtTesto" nel file.
            FileWriter.Write(cncCode.Text)
            FileWriter.Close()
        Catch ex As System.IO.IOException
            MsgBox("Si è verificato un errore durante la scrittura sul file: " & ex.Message)
        Finally
            'Libera le risorse allocate con New.
            FileWriter = Nothing
        End Try
    End Sub
End Class