Option Strict On
 
Imports System.Reflection
Imports System.Net
Imports System.IO
Imports System.Text
Imports System.Xml.Serialization
Imports System.Windows.Forms.Form
 
Public Class WebClientProgressForm
 
  Dim isBusy As Boolean
  Dim _webclient As New WebClient
  'Dim WebClientProgressForm As New WebClientProgressForm
 
  Private Sub webClient_DownloadFileCompleted( _
      ByVal sender As System.Object, _
      ByVal e As System.ComponentModel.AsyncCompletedEventArgs) ' _
      'Handles System.Net.WebClient.DownloadFileCompleted
      isBusy = False
      downloadButton.Text = "Download"
      If e.Error Is Nothing Then
          MessageBox.Show("Download Complete")
      Else
          MessageBox.Show("Download Not Complete: " & e.Error.Message)
      End If
 
  End Sub
 
  Private Sub webClient_DownloadProgressChanged( _
      ByVal sender As System.Object, _
      ByVal e As System.Net.DownloadProgressChangedEventArgs) _
Handles WebClient.DownloadProgressChanged
      downloadProgressBar.Value = e.ProgressPercentage
  End Sub
 
  Private Sub downloadButton_Click( _
      ByVal sender As System.Object, _
      ByVal e As System.EventArgs) _
      Handles downloadButton.Click
      ' If an operation is pending, then the user has clicked cancel.
      If isBusy Then
          _webclient.CancelAsync()
          isBusy = False
          downloadButton.Text = "Download"
          ' Otherwise go ahead and start the download
      Else
          Try
              Dim uri As New Uri(urlTextBox.Text)
              downloadProgressBar.Value = 0
              _webclient.DownloadFileAsync(uri, "localfile.htm")
              downloadButton.Text = "Cancel"
              isBusy = True
          Catch ex As UriFormatException
              MessageBox.Show(ex.Message)
          End Try
      End If
  End Sub
End Class