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| Title | Grab images from a Web page in Visual Basic 6 |
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| Description | This example shows how to grab images from a Web page in Visual Basic 6. It uses a WebBrowser control to go to a Web page. It read that object's Document property to get an HtmlDocument. That object's Images property returns information about the page's images. |
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| Keywords | grab images, Web, HTML, Visual Basic 6, VB 6, WebBrowser, download, download images, screen scraping, HtmlDocument |
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| Categories | Utilities, Internet |
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This description only touches on the most interesting parts of the program. Download it to see the details.
You can click the links on the WebBrowser to navigate to a Web page, or enter a URL and click the Go button to navigate there. The following code shows how the program navigates.
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Private Sub cmdGo_Click()
On Error GoTo BadNavigate
wbrWebSite.Navigate txtUrl.Text
Exit Sub
BadNavigate:
MsgBox "Error navigating to web site " & _
txtUrl.Text & vbCrLf & Err.Description, _
vbOKOnly Or vbExclamation, "Navigation Error"
End Sub
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After you have navigated to the desired Web page, click the Save button to execute the following code.
The code gets the WebBrowser's Document property, which returns an HtmlDocument object representing the Web page, and loops through the HtmlDocument's Images collection. It calls subroutine DownloadPicture for each image, passing the routine the image's src property, which contains the image's URL.
This routine also contains code to let you stop the loop before it finishes. See the code for details.
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Private Sub cmdSaveImages_Click()
Dim doc As HTMLDocument
Dim element As HTMLImg
Dim dir_name As String
If cmdSaveImages.Caption = "Save" Then
Me.MousePointer = vbHourglass
cmdSaveImages.Caption = "Stop"
cmdGo.Enabled = False
DoEvents
' List the images on this page.
dir_name = txtDirectory.Text
If Right$(dir_name, 1) <> "\" Then dir_name = _
dir_name & "\"
Set doc = wbrWebSite.Document
m_Running = True
For Each element In doc.images
DownloadPicture dir_name, element.src
DoEvents
If Not m_Running Then Exit For
Next element
m_Running = False
cmdSaveImages.Caption = "Save"
cmdGo.Enabled = True
Me.MousePointer = vbDefault
lblFile.Caption = "Done"
Beep
Else
m_Running = False
End If
End Sub
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The DownloadPicture subroutine uses an Internet Transfer Control to download a picture. It calls the control's OpenURL method to download the image into a byte array. It then opens the appropriate file and writes the bytes into it.
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Private Sub DownloadPicture(ByVal dir_name As String, ByVal _
url As String)
Dim file_title As String
Dim file_name As String
Dim pos As Integer
Dim bytes() As Byte
Dim fnum As Integer
url = Trim$(url)
If LCase$(Left$(url, 7)) <> "http://" Then url = _
"http://" & url
file_title = url
pos = InStrRev(file_title, "/")
If pos > 0 Then file_title = Mid$(file_title, pos + 1)
file_name = dir_name & file_title
Debug.Print "Copying " & url & " to " & file_name
lblFile.Caption = file_title
lblFile.Refresh
' Get the file.
bytes() = inetDownload.OpenURL(url, icByteArray)
' Save the file.
fnum = FreeFile
Open file_name For Binary Access Write As #fnum
Put #fnum, , bytes()
Close #fnum
End Sub
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This program still has a few weak spots. For example, it doesn't display previews of the images so it doesn't let you pick the images you want to download, it just downloads them all. The .NET version of this program does a better job of letting you pick images for download.
The program also downloads images when it needs them rather than pulling them from cache so it isn't as fast as it might be. It also probably cannot save images that are generated on the fly by the Web server.
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