VB.NET 2010 Console Application Wait for a key for 5 seconds, carry on if not

Question

Ok, so I've tried looking up on several Google sites and cannot find an answer for this.

Its in VB.Net as a Console Application, the way I want to set this up is almost like BIOS entry, when you turn your computer on you have several seconds to press a key, if its not pressed it will skip on, this is easy enough in a Windows Forms application with a timer, but I'm struggling to do it in Console application.

code so far:

   Console.WriteLine("Welcome to console, press F2 for advanced options.")
    ''Console.ReadKey(keys.f2)
    ''Make it pause for 5 seconds, tried obvious threading,thread.sleep(5000) - that halts the application :/

So yeah, if you understand what I mean and are able to help out, anything is appreciated. There doesn't seem to be any obvious timer function. I was thinking of having a variable that slowly increments to 100, and uses thread.sleep, but I think its chance of picking up the key is low because .sleep halts the application. Was also thinking of console.readkey, but unsure how to read a specific key during the wait process.

Possible duplicate of [Impatiently wait for input](https://codegolf.stackexchange.com/q/125332) — GSerg, Jun 12 '17 at 20:10
It would be a minor effort to scroll down and see answers in VB.NET and C#. — GSerg, Jun 12 '17 at 20:16

dbasnett · Accepted Answer · 2017-06-13T21:49:50.630

2

Using a Do loop, Console.KeyAvailable, and a stopwatch

    Console.WriteLine("Welcome to console, press F2 for advanced options.")
    Dim stpw As Stopwatch = Stopwatch.StartNew
    Dim waitfor As New TimeSpan(0, 0, 5)
    Dim kp As ConsoleKeyInfo

    Do
        If Console.KeyAvailable Then
            kp = Console.ReadKey(True)
            If kp.Key = ConsoleKey.F2 Then
                Exit Do
            End If
        End If
        Threading.Thread.Sleep(100)
    Loop While stpw.Elapsed < waitfor

    If kp.Key = ConsoleKey.F2 Then
        Console.WriteLine("F2 press")
    Else
        Console.WriteLine("NO F2")
    End If

edited Jun 13 '17 at 21:49

answered Jun 13 '17 at 11:12

dbasnett

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Works perfectly, how I wanted it as well! :) Wasn't aware of the stopwatch function, even after some research. – Daniel Oakley Jun 13 '17 at 15:43
This is called busy waiting, and it is arguably the worst type of waiting. The code golf solution does not consume processor while waiting for input like it is supposed to be. – GSerg Jun 13 '17 at 16:48
@GSerg - It is. I fixed it. You could post the golf answer unwound. – dbasnett Jun 13 '17 at 21:49
@DanielOakley - note addition of Sleep – dbasnett Jun 13 '17 at 21:51

VB.NET 2010 Console Application Wait for a key for 5 seconds, carry on if not

1 Answers1