سورس كود برنامج تحميل الملفات vb.net 2008

Dim whereToSave As String 
  Delegate Sub ChangeTextsSafe(ByVal length As Long, ByVal position As Integer, ByVal percent As Integer, ByVal speed As Double) 
  Delegate Sub DownloadCompleteSafe(ByVal cancelled As Boolean) 

Public Sub DownloadComplete(ByVal cancelled As Boolean) 
   
    Me.txtFileName.Enabled = True 
    Me.btnDownload.Enabled = True 
    Me.btnCancel.Enabled = False 
    If cancelled Then 
      Me.Label4.Text = "Cancelled" 
      MessageBox.Show("Download aborted", "Aborted") 
    Else 
      Me.Label4.Text = "Successfully downloaded" 
      MessageBox.Show("Successfully downloaded!") 
    End If 
 
    Me.ProgressBar1.Value = 0 
    Me.Label5.Text = "Downloading: " 
    Me.Label6.Text = "Save to: " 
    Me.Label3.Text = "File size: " 
    Me.Label2.Text = "Download speed: " 
    Me.Label4.Text = "" 
 
  End Sub 

Public Sub ChangeTexts(ByVal length As Long, ByVal position As Integer, ByVal percent As Integer, ByVal speed As Double) 
 
    Me.Label3.Text = "File Size: " & Math.Round((length / 1024), 2) & " KB" 
    Me.Label5.Text = "Downloading: " & Me.txtFileName.Text 
    Me.Label4.Text = "Downloaded " & Math.Round((position / 1024), 2) & " KB of " & Math.Round((length / 1024), 2) & "KB (" & Me.ProgressBar1.Value & "%)" 
 
    If speed = -1 Then 
      Me.Label2.Text = "Speed: calculating..." 
    Else 
      Me.Label2.Text = "Speed: " & Math.Round((speed / 1024), 2) & " KB/s" 
    End If 
    Me.ProgressBar1.Value = percent 
 
  End Sub 

Private Sub btnDownload_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDownload.Click 
 
    If Me.txtFileName.Text <> "" AndAlso Me.txtFileName.Text.StartsWith("http://") Then 
 
      Me.SaveFileDialog1.FileName = Me.txtFileName.Text.Split("/"c)(Me.txtFileName.Text.Split("/"c).Length - 1) 
 
      If Me.SaveFileDialog1.ShowDialog = Windows.Forms.DialogResult.OK Then 
        Me.whereToSave = Me.SaveFileDialog1.FileName 
        Me.SaveFileDialog1.FileName = "" 
        Me.Label6.Text = "Save to: " & Me.whereToSave 
        Me.txtFileName.Enabled = False 
        Me.btnDownload.Enabled = False 
        Me.btnCancel.Enabled = True 
        Me.BackgroundWorker1.RunWorkerAsync() 
      End If 
    Else 
      MessageBox.Show("Please insert valid URL for download") 
    End If 
 
  End Sub 
 

Private Sub BackgroundWorker1_DoWork(ByVal sender As System.Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork 
 
 
    Dim theResponse As HttpWebResponse 
    Dim theRequest As HttpWebRequest 
    Try 
      theRequest = WebRequest.Create(Me.txtFileName.Text) 
      theResponse = theRequest.GetResponse 
    Catch ex As Exception 
 
      MessageBox.Show("An error occurred while downloading file. Possibe causes:" & ControlChars.CrLf & _ 
              "1) File doesn't exist" & ControlChars.CrLf & _ 
              "2) Remote server error", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error) 
 
      Dim cancelDelegate As New DownloadCompleteSafe(AddressOf DownloadComplete) 
      Me.Invoke(cancelDelegate, True) 
      Exit Sub 
    End Try 
 
    Dim length As Long = theResponse.ContentLength 
    Dim safedelegate As New ChangeTextsSafe(AddressOf ChangeTexts) 
    Me.Invoke(safedelegate, length, 0, 0, 0) 
    Dim writeStream As New IO.FileStream(Me.whereToSave, IO.FileMode.Create) 
    Dim nRead As Integer 
    Dim speedtimer As New Stopwatch 
    Dim currentspeed As Double = -1 
    Dim readings As Integer = 0 
 
    Do 
      If BackgroundWorker1.CancellationPending Then 
        Exit Do 
      End If 
      speedtimer.Start() 
      Dim readBytes(4095) As Byte 
      Dim bytesread As Integer = theResponse.GetResponseStream.Read(readBytes, 0, 4096) 
      nRead += bytesread 
      Dim percent As Short = (nRead * 100) / length 
      Me.Invoke(safedelegate, length, nRead, percent, currentspeed) 
      If bytesread = 0 Then Exit Do 
      writeStream.Write(readBytes, 0, bytesread) 
      speedtimer.Stop() 
      readings += 1 
      If readings >= 5 Then 
        currentspeed = 20480 / (speedtimer.ElapsedMilliseconds / 1000) 
        speedtimer.Reset() 
        readings = 0 
      End If 
    Loop 
 
 
    theResponse.GetResponseStream.Close() 
    writeStream.Close() 
 
    If Me.BackgroundWorker1.CancellationPending Then 
      IO.File.Delete(Me.whereToSave) 
      Dim cancelDelegate As New DownloadCompleteSafe(AddressOf DownloadComplete) 
      Me.Invoke(cancelDelegate, True) 
      Exit Sub 
    End If 
 
    Dim completeDelegate As New DownloadCompleteSafe(AddressOf DownloadComplete) 
    Me.Invoke(completeDelegate, False) 
 
 End Sub 
 

Private Sub mainForm_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load 
 
    Me.Label4.Text = "" 
 
 End Sub 
 

Private Sub btnCancel_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCancel.Click 
 
    Me.BackgroundWorker1.CancelAsync() 
 
 End Sub