[SOLVED] Preventing queing/preloading a character in the console before Console.ReadKey()

Preventing queing/preloading a character in the console before Console.ReadKey()

When Console.ReadKey(true) is called in .NET, it reads a single keypress from the user into the console. I have noticed that a character can be typed before Console.ReadKey() is actually called, allowing a user to preload a character press before the prompt. I am looking for a way to keep this from happening.

Here is some example code to better explain:

'Code runs a loop for a few seconds'
'...'

'At this point, a user can preload a key press'

Console.WriteLine("Press any key now!")

Dim startTime As DateTimeOffset = DateTimeOffset.Now()
Console.ReadKey(True) 'The console should only look for a keypress at THIS point'
Dim endTime As DateTimeOffset = DateTimeOffset.Now()

Dim miliseconds As Integer = (endTime.Subtract(startTime).TotalMilliseconds)
Dim seconds As Double = (endTime.Subtract(startTime).TotalSeconds)
Console.Clear()
Console.WriteLine("You took {0} miliseconds or {1} second(s).", miliseconds, seconds)

If the user presses a key before the Console.ReadKey(), the sample program will return:

You took 0 miliseconds or 0 second(s).

Is there a known way to prevent this behavior? This problem occurs in other types of console programs where the user is promted to enter a specific key. If the key is pressed early, sometimes the user won't even see the prompt.

Solution

Below code can help you .. with test case..

Private Shared Sub Main(args As String())

    'System.Threading.Thread.Sleep(4000)

    'rejecting old key presses
    While Console.KeyAvailable
        Console.ReadKey()
    End While

    Console.ReadKey()
End Sub