Hatasız Çalışan Downloader

 
  Imports System.Net 
  Public Class Form1 
      Private WithEvents httpclient As WebClient 
      Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click 
          Dim save As New SaveFileDialog 
          save.Title = ("Has Downloader:Kaydedilecek Yer") 
          save.ShowDialog() 
          TextBox2.Text = save.FileName 
      End Sub 
   
      Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click 
          httpclient = New WebClient 
          Dim sourceURL = TextBox1.Text 
          Dim filedir = TextBox2.Text 
          ProgressBar1.Value = 0 
          ProgressBar1.Maximum = 100 
          Try 
              httpclient.DownloadFileAsync(New Uri(sourceURL), (filedir)) 
          Catch ex As Exception 
              MsgBox("İndirme Başarısız" + ErrorToString(), MsgBoxStyle.Critical) 
          End Try 
      End Sub 
   
      Private Sub httpclient_DownloadProgressChanged(sender As Object, e As DownloadProgressChangedEventArgs) Handles httpclient.DownloadProgressChanged 
          ProgressBar1.Value = e.ProgressPercentage 
      End Sub 
  End Class