VB6 Downloading file with progress bar and KBP/S

Here is an example of what you require.

A URLDownloadToFile Demo WITH PROGRESS bar/CANCEL

sorry that link again

http://www.planet-source-code.com/vb/scripts/ShowCode.asp?txtCodeId=64914&lngWId=1

You might need to determine if your server returns the content-length header of the file in bytes, otherwise you won't know the size of the file to calculate the progress.
You can use the following code to check if it returns the size of the requested file

Option Explicit

Private Const WININET_API_FLAG_SYNC = &H4&
Private Const HTTP_QUERY_CONTENT_LENGTH = &H5&
Private Const HTTP_QUERY_FLAG_NUMBER = &H20000000

Private Declare Function InternetOpenW Lib "wininet" (ByVal lpszAgent As Long, ByVal dwAccessType As Long, ByVal lpszProxyName As Long, ByVal lpszProxyBypass As Long, ByVal dwFlags As Long) As Long
Private Declare Function InternetOpenUrlW Lib "wininet" (ByVal hInternet As Long, ByVal lpszUrl As Long, ByVal lpszHeaders As Long, ByVal dwHeadersLength As Long, ByVal dwFlags As Long, ByVal dwContext As Long) As Long
Private Declare Function InternetCloseHandle Lib "wininet" (ByVal hInternet As Long) As Long
Private Declare Function HttpQueryInfoW Lib "wininet.dll" (ByVal hRequest As Long, ByVal dwInfoLevel As Long, ByRef lpvBuffer As Long, ByRef lpdwBufferLength As Long, ByRef lpdwIndex As Long) As Long

Public Function GetContentLength(ByVal url As String) As Long
    Dim hInternet       As Long
    Dim hRequest        As Long
    Dim dwFileSize      As Long
    Dim dwLength        As Long
    Dim dwIndex         As Long
    dwLength = 4 ' DWORD 32 bit value buffer length.
    hInternet = InternetOpenW(0, 1, 0, 0, WININET_API_FLAG_SYNC)
    hRequest = InternetOpenUrlW(hInternet, StrPtr(url), 0, 0, 0, 0)
    If HttpQueryInfoW(hRequest, HTTP_QUERY_CONTENT_LENGTH Or HTTP_QUERY_FLAG_NUMBER, _
        dwFileSize, dwLength, dwIndex) Then
        GetContentLength = dwFileSize
    Else
        GetContentLength = (-1)
    End If
    InternetCloseHandle hRequest
    InternetCloseHandle hInternet
End Function

Private Sub Form_Load()
    Debug.Print GetContentLength("http://www.google.com/intl/en_ALL/images/logos/images_logo_lg.gif")
End Sub

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Hey,

It does return the correct size.

What next?

Thanks,
Jessee

Hey,

How do I change it to Progress bar format?
I tried:
frmDownload.PgbProgress.Max = dwFileSize
frmDownload.PgbProgress.Value = dwBytesWritten

The progress bar values should be in the range 0-100 as the example calculates the percentage.

frmDownload.PgbProgress.Value = dwPercent

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Hey,

Sweet. Im now getting a CreateFile error 32?

The file handle is still opened usually happens when your debugging and the IDE throws an error and the CloseHandle() never had a chance to cleanup the handle. You have to close out the IDE or application then start fresh.

Hey,

So if I was running this as a .exe it wouldnt come up with this error?
Just restarted vb6 and it fixed it :)

Do you know of a way to find out the KBP/S?

What happens is that in the IDE if you would click the Stop or a Debugging error occured before the download completed the executing code would never have cleaned up the opened file handle. You can extend the example by adding a cancel flag that exits the loop if it's in progress so that the call to CloseHandle() will always cleanup the handle then you won't have to be concerned with this error, you also have to make sure that the location you download has write access permissions.
 

Ah I see what you mean now.

Are you able to help with the KBPS?

Calculate how many bytes have been read every second and divide by 1000. You then might need to take the overhead of time of the WriteFile() call to get the closest result.
Disable the timer and make the Interval 1000, just before the Loop begins enable the timer and then after loop disable the timer.
If your working with a small file I wouldn't even bother calculating the transfer rate , just show how many bytes have been completed of the file instead.

Thanks :)