Imports System

Imports System.IO

Public Class Form1

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        Using ofd As New OpenFileDialog

            ofd.Filter = "ZipFile|*.zip"

            If ofd.ShowDialog = Windows.Forms.DialogResult.OK Then

                Dim file As String = ofd.FileName

                Dim cu As New ClassUnzip(file, Path.Combine(Path.GetDirectoryName(file), "test_unzip_folder"))

                AddHandler cu.UnzipFinishd, AddressOf Unziped

                cu.UnzipNow()

            End If

        End Using

    End Sub

    Private Sub Unziped()

        MessageBox.Show("Unzipping finished")

    End Sub

End Class