I am creating a file downloader using backgroundworker & i want to save the progress of backgroundworker so that when i restart the application, on resume, it start the download where i closed last time.
Any help ? Here is My code for Downloader
Public Class cls_FileDownloader
Dim FileSave As String
Delegate Sub DownloadFIlesafe(ByVal Cancelled As Boolean)
Delegate Sub ChangeTextsSafe(ByVal length As Long, ByVal position As Double, ByVal percent As Long, ByVal speed As Long)
Private Sub cls_FileDownloader_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Label1.Text = ""
btn_Cancel.Enabled = False
End Sub
Private Sub btn_Download_Click(sender As Object, e As EventArgs) Handles btn_Download.Click
If Me.txt_Url.Text <> "" Then
Me.SaveFile.FileName = txt_Url.Text.Split("\"c)(txt_Url.Text.Split("\"c).Length - 1)
If SaveFile.ShowDialog = System.Windows.Forms.DialogResult.OK Then
FileSave = SaveFile.FileName
SaveFile.FileName = ""
lbl_SaveTO.Text = "Save To:" & FileSave
txt_Url.Enabled = False
btn_Download.Enabled = False
btn_Cancel.Enabled = True
bg_Worker.RunWorkerAsync()
End If
Else
MessageBox.Show("Please Insert valid file path", "Warning", MessageBoxButtons.OK, MessageBoxIcon.Warning)
End If
End Sub
Private Sub bg_Worker_DoWork(sender As Object, e As DoWorkEventArgs) Handles bg_Worker.DoWork
Dim response As FileWebResponse
Dim request As FileWebRequest
Try
request = WebRequest.Create(txt_Url.Text)
response = request.GetResponse
Catch ex As Exception
MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
Dim cancelDelegate As New DownloadFIlesafe(AddressOf Download_Complete)
Me.Invoke(cancelDelegate, True)
Exit Sub
End Try
Dim length As Long = response.ContentLength
Dim safedelegate As New ChangeTextsSafe(AddressOf ChangeTexts)
Me.Invoke(safedelegate, length, 0, 0, 0)
Dim writeStream As New IO.FileStream(Me.FileSave, IO.FileMode.Create)
Dim nRead As Double
'To calculate the download speed
Dim speedtimer As New Stopwatch
Dim currentspeed As Long = -1
Dim readings As Integer = 0
Do
If bg_Worker.CancellationPending Then 'If user abort download
Exit Do
End If
speedtimer.Start()
Dim readBytes(4095) As Byte
Dim bytesread As Long = response.GetResponseStream.Read(readBytes, 0, 4096)
nRead += bytesread
Dim percent As Long = (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 'For increase precision, the speed it's calculated only every five cicles
currentspeed = 20480 / (speedtimer.ElapsedMilliseconds / 1000)
speedtimer.Reset()
readings = 0
End If
Loop
'Close the streams
response.GetResponseStream.Close()
writeStream.Close()
If Me.bg_Worker.CancellationPending Then
IO.File.Delete(Me.FileSave)
Dim cancelDelegate As New DownloadFIlesafe(AddressOf Download_Complete)
Me.Invoke(cancelDelegate, True)
Exit Sub
End If
Dim completeDelegate As New DownloadFIlesafe(AddressOf Download_Complete)
Me.Invoke(completeDelegate, False)
End Sub
