NET StandardInput - Problem

Private Sub start()
  _Process2 = New Process With {.EnableRaisingEvents = True}
            With _Process2.StartInfo
                .CreateNoWindow = True
                .UseShellExecute = False
                .Verb = "runas"  
                .FileName = "cmd"  
                .Arguments = ("/k " & TxbCommand.Text)  
                .WorkingDirectory = vari.Folder
                .RedirectStandardOutput = True
                .RedirectStandardInput = True
            End With
            _Process2.Start()
            _Process2.BeginOutputReadLine()
           End Sub

    Private Sub _Process2_OutputDataReceived(sender As Object, e As DataReceivedEventArgs) Handles _Process2.OutputDataReceived
        BeginInvoke(Sub() OutputData(e.Data))
    End Sub

    Private Sub OutputData(txt As String)
        RichTextBox1.AppendText(txt & vbNewLine)
        RichTextBox1.Select(RichTextBox1.TextLength, 0)
        RichTextBox1.ScrollToCaret()
    End Sub


Private Sub btnStatus_Click(sender As Object, e As EventArgs) Handles btnStatus.Click
 _Process2.StandardInput.WriteLine("t")  
End Sub