Delete file after "x" second after creation - vb.net

Question

I want to delete file after 15 second of create that file.
I use this code but no success.
Private Sub Form1_Click(sender As Object, e As EventArgs) Handles Me.Click
Dim test = Application.StartupPath & "\" + tte4
Timer1.Enabled = True
If Timer1.Interval = 0 Then
My.Computer.FileSystem.DeleteFile(test)
End If
End Sub

Answer 1

You must handle the timed event in a handler for the Timer's Tick Event (or Elapsed if using System.Timers.Timer):
Private m_strTest As String = String.Empty
Private Sub Form1_Click(sender As Object, e As EventArgs) Handles Me.Click
m_strTest = Application.StartupPath & "\" + tte4
Timer1.Enabled = True
End Sub
If using System.Forms.Timer (most likely):
Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
System.IO.File.Delete(m_strTest)
Timer1.Enabled = False
End Sub
If using System.Timers.Timer:
Private Sub Timer1_Elapsed(ByVal source As Object, ByVal e As ElapsedEventArgs) Handles Timer1_Elapsed
System.IO.File.Delete(m_strTest)
Timer1.Stop()
End Sub
If you added your Timer from the Toolbox, the above code will work (due to WithEvents). If you added it programatically, you'll also have to wire up the Event Handler and remove the Handles from your Timer1_Tick Method:
Private Sub Form1_Click(sender As Object, e As EventArgs) Handles Me.Click
m_strTest = Application.StartupPath & "\" + tte4
AddHandler Timer1.Tick, AddressOf Timer1_Tick
Timer1.Enabled = True
End Sub
Private Sub Timer1_Tick(sender As Object, e As EventArgs)
System.IO.File.Delete(m_strTest)
Timer1.Enabled = False
End Sub

Answer 2

You need define a method that the timer fires when the interval elapses.
' Timer set to fire every 15 seconds
Dim Timer1 As New Timer(15000)
' OnTimedEvent is the method that will fire after 15 seconds
AddHandler Timer1.Elapsed, AddressOf OnTimedEvent
' Start the Timer
Timer1.Start()
The OnTimedEvent is as followed:
Private Sub OnTimedEvent(source As Object, e As ElapsedEventArgs)
' Stop the timer from firing again
Timer1.Stop()
' Delete your file
End Sub
Reference
https://msdn.microsoft.com/en-us/library/k0wdddfy(v=vs.110).aspx?cs-save-lang=1&cs-lang=vb#code-snippet-1

Answer 3

You have the right idea in using a Timer to wait for the deletion, but your way of trying to use it is incorrect. A (System.Windows.Forms) Timer raises an event when it ticks, and you need to tie that event to the code you want to run.
Also, to combine parts of a path it is better to use IO.Path.Combine, and when doing file operations it is a good idea to "wrap" the relevant code in a Try..Catch construct and handle the exception if it happens.
So:
Option Infer On
Option Strict On
Imports System.IO
Public Class Form1
Dim tim1 As New System.Windows.Forms.Timer
Dim tte4 As String = "afile.txt"
Private Sub Timer1_Tick(sender As Object, e As EventArgs)
tim1.Enabled = False
Dim target = Path.Combine("C:\temp", tte4)
If File.Exists(target) Then
Try
File.Delete(target)
Catch ex As Exception
MessageBox.Show(String.Format("The file ""{0}"" could not be deleted because {1}", target, ex.Message))
End Try
Else
' the file does not exist - do something if required
End If
End Sub
Private Sub SetUpTimer()
tim1.Enabled = False
tim1.Interval = 1000 * 15
' here we tie the event to the code
AddHandler tim1.Tick, AddressOf Timer1_Tick
End Sub
Private Sub Form1_Click(sender As Object, e As EventArgs) Handles MyBase.Click
' this has the side-effect of trying to delete a file after an interval
tim1.Enabled = True
End Sub
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
SetUpTimer()
End Sub
End Class
You did not show code for creating the file - I assume you used a click on the form just to demonstrate the idea.