Visual Basic

backgroundworker1.cancleasync()

Public Class Form1

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        For Each ctl As Control In Me.Controls
            If TypeOf ctl Is Button Then
                If ctl.Text.Length = 1 Then
                    AddHandler ctl.Click, AddressOf btnKey_Click
                End If
            End If
        Next
    End Sub

    Private Sub btnKey_Click(ByVal sender As Object, ByVal e As System.EventArgs)
        TextBox1.Focus()
        SendKeys.Send(sender.text)
        
    End Sub

End Class

Public Class Form1
    Private _timer As Timer
    Private _timerdisable As Timer

    Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        _timer = New Timer(500)
        _timer.AutoReset = True
        AddHandler _timer.Elapsed, AddressOf Timer_Elapsed
        _timer.Enabled = True

        _timerdisable = New Timer(5000)
        _timerdisable.AutoReset = True
        AddHandler _timerdisable.Elapsed, AddressOf TimerDisable_Elapsed
    End Sub

    Private Sub Timer_Elapsed(ByVal sender As Object, ByVal e As System.Timers.ElapsedEventArgs)
        If Me.InvokeRequired Then
            Me.Invoke(New Action(Of Object, System.Timers.ElapsedEventArgs)(AddressOf Timer_Elapsed), Nothing, Nothing)
            Exit Sub
        End If

        Me.Text = Me.Enabled.ToString & "::" & Now.ToString
    End Sub

    Private Sub TimerDisable_Elapsed(ByVal sender As Object, ByVal e As System.Timers.ElapsedEventArgs)
        If Me.InvokeRequired Then
            Me.Invoke(New Action(Of Object, System.Timers.ElapsedEventArgs)(AddressOf TimerDisable_Elapsed), Nothing, Nothing)
            Exit Sub
        End If

        '----
        'stop the timer so it doesn't disable the form again.
        If Not Me.Enabled Then _timerdisable.Enabled = False
        '-----
        Me.Enabled = Not Me.Enabled
    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click
        _timerdisable.Enabled = True
        MsgBox("HEY")
    End Sub
End Class