Public Class Form1
    Private CurrentTime As TimeSpan
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button1.Click
        Me.CurrentTime = New TimeSpan(0, Convert.ToInt32(Me.TextBox1.Text), 0)
 
        Me.Timer1.Start()
    End Sub
 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles MyBase.Load
        Me.Timer1.Interval = 1000
    End Sub
 
    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button2.Click
        With Me.Timer1
            If .Enabled Then
                .Stop()
            Else
                .Start()
            End If
        End With
    End Sub
 
    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button3.Click
        Me.Timer1.Stop()
    End Sub
 
    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Timer1.Tick
        With Me.CurrentTime
            Me.CurrentTime = TimeSpan.FromTicks(.Ticks).Subtract(New TimeSpan( _
              0, 0, 1))
 
            Me.Label1.Text = String.Format("{0}:{1}", .Minutes.ToString("D2"), _
              .Seconds.ToString("D2"))
 
            If .Ticks <= 0 Then
                Me.Timer1.Stop()
            End If
        End With
    End Sub
End Class
 
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