Imports System.Threading.Tasks
 
Public Class Form1
 
    ''' <summary>
    ''' The CMD <see cref="System.Diagnostics.Process"/> instance.
    ''' </summary>
    Private WithEvents cmdProcess As New Process With
        {
            .EnableRaisingEvents = True,
            .StartInfo = New ProcessStartInfo With
                             {
                                .FileName = "cmd.exe",
                                .Arguments = String.Empty,
                                .RedirectStandardInput = False,
                                .RedirectStandardOutput = True,
                                .RedirectStandardError = True,
                                .UseShellExecute = False,
                                .CreateNoWindow = True
                             }
        }
 
    ''' <summary>
    ''' Gets the ping commandline arguments.
    ''' </summary>
    Private ReadOnly Property PingArguments As String
        Get
            Return String.Format("ping.exe ""{0}.{1}.{2}.{3}""",
                                TextBox1.Text, TextBox2.Text,
                                TextBox3.Text, TextBox4.Text)
        End Get
    End Property
 
    Private Sub btnSend_Click(ByVal sender As Object, ByVal e As EventArgs) _
    Handles btnsend.Click
 
        Task.Factory.StartNew(AddressOf CMDAutomate)
 
    End Sub
 
    Private Sub CMDAutomate()
 
        With Me.cmdProcess
 
            .StartInfo.Arguments = String.Format("/C ""{0}""", Me.PingArguments)
            .Start()
            .BeginOutputReadLine()
            .BeginErrorReadLine()
            .WaitForExit()
 
        End With
 
    End Sub
 
    ''' <summary>
    ''' Occurs when an application writes to its redirected <see cref="System.Diagnostics.Process.StandardOutput"/> stream.
    ''' Occurs when an application writes to its redirected <see cref="System.Diagnostics.Process.StandardError"/>  stream.
    ''' </summary>
    Private Sub cmdProcess_OutputDataReceived(ByVal sender As Object, ByVal e As DataReceivedEventArgs) _
    Handles cmdProcess.OutputDataReceived,
            cmdProcess.ErrorDataReceived
 
        Select Case txtResults.InvokeRequired
 
            Case True
                txtResults.Invoke(Sub() txtResults.AppendText("" & e.Data))
                txtResults.Invoke(Sub() txtResults.AppendText(Environment.NewLine))
 
            Case Else
                txtResults.AppendText(e.Data)
                txtResults.AppendText(Environment.NewLine)
 
        End Select
 
#If DEBUG Then
        ' Debug.WriteLine(e.Data)
#End If
 
    End Sub
 
    ''' <summary>
    ''' Occurs when a <see cref="System.Diagnostics.Process"/> exits.
    ''' </summary>
    Private Sub cmdProcess_Exited(ByVal sender As Object, ByVal e As EventArgs) _
    Handles cmdProcess.Exited
 
        Debug.WriteLine(String.Format("cmdProcess has exited with exit code: {0}",
                                      DirectCast(sender, Process).ExitCode))
 
    End Sub
 
End Class

#Region " TASK Example "
 
Public Class Form1
 
    ' NORMAL TASK USAGE:
    ' ------------------
    Private Task1 As Threading.Tasks.Task
    Private Task1CTS As New Threading.CancellationTokenSource
    Private Task1CT As Threading.CancellationToken = Task1CTS.Token
 
    Private Sub MyTask1(ByVal CancellationToken As Threading.CancellationToken)
 
        For x As Integer = 0 To 9999
 
            If Not CancellationToken.IsCancellationRequested Then
                Debug.Print("Task1: " & x)
            Else
                MsgBox(String.Format("Task1 Canceled at ""{0}""", x))
                Exit Sub
            End If
 
        Next x
 
    End Sub
 
    ' ANONYMOUS TASK METHOD:
    ' ---------------------
    Private Task2 As Threading.Tasks.Task
    Private Task2CTS As New Threading.CancellationTokenSource
    Private Task2CT As Threading.CancellationToken = Task2CTS.Token
 
    Private Delegate Function Task2Delegate(ByVal CancellationToken As Threading.CancellationToken)
 
    Private MyTask2 As Task2Delegate =
      Function(CancellationToken As Threading.CancellationToken) As Boolean
 
          For x As Integer = 0 To 9999
 
              If Not CancellationToken.IsCancellationRequested Then
                  Debug.Print("Task2: " & x)
              Else
                  MsgBox(String.Format("Task2 Canceled at ""{0}""", x))
                  Return False
              End If
 
          Next x
 
          Return True
 
      End Function
 
    Private Sub TaskTest() Handles MyBase.Shown
 
        ' Run an asynchronous Task.
        Task1 = Threading.Tasks.Task.Factory.StartNew(Sub() MyTask1(Task1CT), Task1CT)
 
        ' Wait 2 seconds (Just to demonstrate this example)
        Threading.Thread.Sleep(2 * 1000)
 
        ' Cancel the Task.
        Task1CTS.Cancel()
 
        ' Wait for the Task to finish the being cancelled.
        Task1.Wait()
 
        ' Show the task status
        MsgBox(Task1.Status.ToString) ' Result: RanToCompletion
 
        ' ReStart the Task1.
        Task1 = Threading.Tasks.Task.Factory.StartNew(Sub() MyTask1(Task1CT), Task1CT)
 
        ' Start the Task2
        Task2 = Threading.Tasks.Task.Factory.StartNew(Of Boolean)(Function() MyTask2(Task2CT), Task2CT)
 
        ' Wait for both Tasks to finish their execution.
        Threading.Tasks.Task.WaitAll()
 
    End Sub
 
End Class
 
#End Region

Imports System.Threading
Imports System.Threading.Tasks
 
Public Class Form1
 
    Private cmdTask As Task
    Private cmdTaskCTS As New CancellationTokenSource
    Private cmdTaskCT As CancellationToken
 
    ''' <summary>
    ''' The CMD <see cref="System.Diagnostics.Process"/> instance.
    ''' </summary>
    Private WithEvents cmdProcess As New Process With
        {
            .EnableRaisingEvents = True,
            .StartInfo = New ProcessStartInfo With
                             {
                                .FileName = "cmd.exe",
                                .Arguments = String.Empty,
                                .RedirectStandardInput = False,
                                .RedirectStandardOutput = True,
                                .RedirectStandardError = True,
                                .UseShellExecute = False,
                                .CreateNoWindow = True
                             }
        }
 
    ''' <summary>
    ''' Gets the ping commandline arguments.
    ''' </summary>
    Private ReadOnly Property PingArguments As String
        Get
            Return String.Format("ping.exe -t ""{0}.{1}.{2}.{3}""",
                                TextBox1.Text, TextBox2.Text,
                                TextBox3.Text, TextBox4.Text)
        End Get
    End Property
 
    Private Sub btnSend_Click(ByVal sender As Object, ByVal e As EventArgs) _
    Handles btnsend.Click
 
        Me.StartTask()
 
    End Sub
 
    Private Sub CMDAutomate()
 
        With Me.cmdProcess
 
            .StartInfo.Arguments = String.Format("/C ""{0}""", Me.PingArguments)
            .Start()
            .BeginOutputReadLine()
            .BeginErrorReadLine()
            .WaitForExit(Integer.MaxValue)
 
        End With
 
    End Sub
 
    ''' <summary>
    ''' Occurs when an application writes to its redirected <see cref="System.Diagnostics.Process.StandardOutput"/> stream.
    ''' Occurs when an application writes to its redirected <see cref="System.Diagnostics.Process.StandardError"/>  stream.
    ''' </summary>
    Private Sub cmdProcess_OutputDataReceived(ByVal sender As Object, ByVal e As DataReceivedEventArgs) _
    Handles cmdProcess.OutputDataReceived,
            cmdProcess.ErrorDataReceived
 
        Select Case txtresults.InvokeRequired
 
            Case True
                txtresults.Invoke(Sub() txtresults.AppendText("" & e.Data))
                txtresults.Invoke(Sub() txtresults.AppendText(Environment.NewLine))
 
            Case Else
                txtresults.AppendText(e.Data)
                txtresults.AppendText(Environment.NewLine)
 
        End Select
 
#If DEBUG Then
        ' Debug.WriteLine(e.Data)
#End If
 
    End Sub
 
    ''' <summary>
    ''' Occurs when a <see cref="System.Diagnostics.Process"/> exits.
    ''' </summary>
    Private Sub cmdProcess_Exited(ByVal sender As Object, ByVal e As EventArgs) _
    Handles cmdProcess.Exited
 
        Debug.WriteLine(String.Format("cmdProcess has exited with exit code: {0}",
                                      DirectCast(sender, Process).ExitCode))
 
    End Sub
 
    Private Sub LinkLabel1_LinkClicked(sender As Object, e As LinkLabelLinkClickedEventArgs) _
    Handles LinkLabel1.LinkClicked
 
        ' limpio el texto de cada textbox.
        For Each tb As TextBox In Me.Controls.OfType(Of TextBox)()
            tb.Clear()
        Next tb
 
        ' cancelo la tarea en segundo plano.
        Me.CancelTask()
 
    End Sub
 
    Private Sub StartTask()
 
        Me.cmdTask = Task.Factory.StartNew(AddressOf CMDAutomate)
        Me.cmdTaskCTS = New Threading.CancellationTokenSource
        Me.cmdTaskCT = cmdTaskCTS.Token
 
    End Sub
 
    Private Sub CancelTask()
 
        ' Si el proceso no se ha detenido...
        If Not Me.cmdProcess.HasExited Then
 
            With Me.cmdProcess
                ' cancelo la lectura de los outputs.
                .CancelOutputRead()
                .CancelErrorRead()
                .Kill() ' mato el proceso (cmd.exe)
            End With
 
            ' Cancelo la tarea en segundo plano.
            Me.cmdTaskCTS.Cancel()
            ' Espero a que la tarea se haya cancelado.
            Me.cmdTask.Wait()
 
        End If
 
    End Sub
 
End Class

.WaitForExit(Integer.MaxValue)