[RESOLVED] Website login with WebBrowser and VB.Net 2010

[Mark@SF]

I am converting an old Access database application over to VB.Net and have run into an issue that I need some help with. In the Access (VBA) application I can automatically login to various websites, but I can't get this to work in VB.Net. In the VB.Net code I am using a WebBrowser to navigate to a website.

Here is the my old VBA code (that works like a charm):

  Set objIE = CreateObject("InternetExplorer.Application")

  StatusBar "Opening the login window, please wait..."
  objIE.navigate (strURL)
  Do While objIE.busy
    '...wait for IE to load page
  Loop
  
  Set objHTMLDoc = objIE.Document
    
  '...wait until the key node is visible
  flgOK = False: lngStart = Timer
  Do While flgOK = False
    For Each objInput In objHTMLDoc.all.tags("INPUT")
      Debug.Print objInput.nodeName, objInput.Name, objInput.Value
      If objInput.Value = "User Name" Then
        flgOK = True
        Exit For
      End If
    Next objInput
    If (Timer - lngStart) > 15 Then Exit Do   '...quit after 15 seconds if search text hasn't been found
  Loop

  '...complete site login information
  StatusBar "Completing login procedure, please wait..."
  If flgOK = True Then
    For Each objInput In objHTMLDoc.all.tags("INPUT")
      If objInput.Name = "vb_login_username" Then
        objInput.Value = strUN
      ElseIf objInput.Name = "vb_login_password" Then
        objInput.Value = strPW
      ElseIf objInput.Value = "Log in" Then
        objInput.Click
        MsgBox "Login complete.", vbOKOnly + vbInformation
        objIE.Visible = True
        Exit For
      End If
    Next objInput
  Else
    MsgBox "Cannot locate key input node.", vbOKOnly + vbCritical
  End If

Here is the my VB.Net code (that I'm having trouble with):

            wbc.ScriptErrorsSuppressed = True
            wbc.Navigate(strURL)
            timer = Stopwatch.StartNew
            flgTimedOut = False
            Do Until wbc.ReadyState = WebBrowserReadyState.Complete
                If timer.Elapsed.Seconds > intTimeOut Then
                    flgTimedOut = True
                    Exit Do
                End If
                Application.DoEvents()
            Loop

            If (wbc.Document IsNot Nothing) Then

                wbc.Document.GetElementById("navbar_username").SetAttribute("Value", strUN)
                wbc.Document.GetElementById("navbar_password").SetAttribute("Value", strPW)

                'the "Log in" button does not have an ID, so find it by its TabIndex and OuterHTML values
                For i As Integer = 0 To wbc.Document.GetElementsByTagName("Input").Count
                    With wbc.Document.GetElementsByTagName("Input").Item(i)
                        Debug.WriteLine("Input #" & i & ": " & .Name & ", TabIndex = " & .TabIndex)
                        Debug.WriteLine(.OuterHtml)
                        If .TabIndex = 104 And InStr(.OuterHtml, "Enter your username and password") <> 0 Then
                            .InvokeMember("click")
                            wbc.Visible = True
                            If Not flgSilent Then
                                MessageBox.Show("Operation complete (" & timer.Elapsed.ToString("hh\:mm\:ss") & ").", _
                                                "VBForums Login", MessageBoxButtons.OK, MessageBoxIcon.Information)
                            End If
                            Exit For
                        End If
                    End With
                Next

            Else
                MessageBox.Show("Browser navigation did not complete in the alloted time (" & intTimeOut.ToString & _
                                If(intTimeOut = 1, " second", " seconds") & ").", "VBForums Login", MessageBoxButtons.OK, MessageBoxIcon.Warning)
            End If '(wbc.Document IsNot Nothing)

When I single-step through the code I can see that the "strUN" and "strPW" values are being assigned to the navbar_username and navbar_password elements and the InvokeMember("click") is happening. The "Operation complete" MessageBox appears and there are no errors raised. Having said that, the webpage never appears. The Windows Task Manager never shows an instance of Internet Explorer (iexplore.exe) in its Processes tab page.

I'm stumped. Can anyone give me some advice?

[dunfiddlin]

and there are no errors raised

Odd .... oh, wait ...

wbc.ScriptErrorsSuppressed = True

[Mark@SF]

There are also no errors raised when the "ScriptErrorsSuppressed = True" line is removed.

[Mark@SF]

When I immediately run the code a second time, it raises err #91 ("Object reference not set to an instance of an object.") at the following line:

wbc.Document.GetElementById("navbar_username").SetAttribute("Value", strUN)

[dunfiddlin]

Ok then. Had to check obviously. Are you sure that this button has a 'click' to invoke? It's not 'onclick', for example? Or a simple anchor? Have you tried double clicking (I've found that some sites absorb the first click in focussing on the button), possibly with a delay in the middle? Have you tried with the browser visible before the log-in? Have you done the process up to the click and then manually clicked to see that it works?

What I'm trying to say her is that it's a very inexact science and if push comes to shove your best bet may just be to position the cursor over the button and create a mouse click. This process above all others is the one that puts the trial in trial and error!

[dunfiddlin]

Oh, and this ....

timer = Stopwatch.StartNew
flgTimedOut = False
Do Until wbc.ReadyState = WebBrowserReadyState.Complete
If timer.Elapsed.Seconds > intTimeOut Then
flgTimedOut = True
Exit Do
End If
Application.DoEvents()
Loop

... is not good at all (and not just because you never appear to stop the watch!!!!!)

[Mark@SF]

Good catch on the timer...I should have a timer.Stop() before my Exit For statement!

As for the "click" vs. "onclick" events, I'm pretty sure that its a "click" event because my old VBA code (that still works) uses the "click" event. You can see this in the VBA code that I included in my initial post.

The line from the webpage's source HTML is (I'm trying to automatically log into the VBForums website page):

<input type="submit" class="loginbutton" tabindex="104" value="Log in" title="Enter your username and password in the boxes provided to login, or click the 'register' button to create a profile for yourself." accesskey="s" />

What don't you like about my "Application.DoEvents()" approach? Can you suggest an alternate approach?

[Mark@SF]

dunfiddlin, I appreciate your help here. You suggested several trial and error ideas to investigate the problem. A few of them require that the WebBrowser be visible. Even though it is not visible at any point when the code runs, "?wbc.visible" equals TRUE in the Immediate Window. Like I said, I'm really stumped!

[dunfiddlin]

VBA .Click and VB.Net HTML Element InvokeMember are not at all the same thing unfortunately. T'would be folly to assume that they are equivalent.

In the meantime if you want to see grown men crying, gnashing their teeth, and generally blasting demons with extreme prejudice, just enter Application.DoEvents() in the search box! It's not pretty.

We've also has endless discussions about how to ensure that a webpage is fully loaded with less than spectacular results so you may care to look those up too. These days I use the Awesomium browser in my applications as it's loaded document tracking seems to be considerably superior to the standard control.

[Mark@SF]

Thanks for the tip on the Awesomium browser, I'll look into it.

I've attached an image that shows that VB.Net thinks that the WebBrowser is visible during the execution of the program just so you don't think I've completely lost my mind .

[Mark@SF]

I think I have figured out what is the issue. In my VBA code (Microsoft Access), I was opening an instance of the Internet Explorer via the CreateObject("InternetExplorer.Application") statement. This instance of IE was separate from MS Access so after the website login was completed, I could work in the website regardless of whether or not my Access VBA application was still running. In my VB.Net code, I was creating a WebBrowser control within the VB.Net application itself, but I had not added the WebBrowser control to my VB.Net form. So when I used the WebBrowser control to navigate to a website, it performed the navigation but since the WebBrowser control was not on a form I couldn't see the webpage it navigated to.

My solution to this issue was to use the CreateObject("InternetExplorer.Application") statement in my VB.Net code to create an instance of IE that is separate from my VB.NET application. That way, my application can automatically log into the website and then close itself without also closing IE and the webpage.

If there are better ways to do this, instead of the CreateObject("InternetExplorer.Application") statement, I'd like to hear about them.