Using HTML controls in a VB application?

[bgerby]

Same issue as mooman_fl

 

mooman_fl or anyone else,

 

Has anyone found a solution. I can capture document events using addHandler, but I cannot then return focus to the browser so it can act normally. In a nutshell, I want to capture the event when someone makes a selection.

[vsdotnetguy]

There is a bug in the COM Interop between mshtml and .Net. I have received both a VB and C# based workaround from MS. Which do you require?

[bgerby]

VB.NET

 

VB.NET

[mooman_fl]

by all means... post the VB.NET workaround. Still haven't gotten this problem solved.

[vsdotnetguy]

Here is vbrevised.zip attachment

 

From Lauru Xu of MS...

 

The whole problem is related to how delegate classes are implemented (especially when event handler return type has some meaning). So the onclick handler is returning false even when you are returning true from your code. This behavior seems to be by design. When creating COM event sinks in .NET it is natural to use delegates. However, when an event sink contains more than one method, the delegate model may not preserve the return value. The delegate model may also introduce other overhead that is not desirable. When .NET hooks a delegate to a sink interface, it generates an entire sink but only passes on the call for the one method wrapped by the delegate. The rest of the event methods in the generated sink return a default value.

Fortunately, there is another way to hook up to a COM event interface from managed code. The workaround is to use connection points.

 

You could hook up to a COM event interface from managed code. You can use the COM connection point interfaces. All COM event classes provide the IConnectionPointContainer interface. When you have the IConnectionPointContainer interface, you must find the specific connection point for the event interface to which you want to subscribe. To do this, follow these steps:

1. Use a FindConnectionPoint call to obtain the IConnectionPoint

interface.

 

2. To subscribe to the event, provide the IConnectionPoint::Advise

method with an instance of a class that is inheriting from the event interface.

 

In the .NET Framework libraries, the names of the COM connection point interfaces are located in the System.Runtime.InteropServices namespace, as in the following table:

 

+============================+============================+

| COM Interface Name | .NET Class Name |

+============================+============================+

| IConnectionPointContainer | UCOMIConnectPointContainer |

+============================+============================+

| IConnectionPoint | UCOMIConnectionPoint |

+============================+============================+

 

 

Establish a COM Event Sink

To establish a COM event sink, follow these steps:

 

1. Create the class that will sink (handle) the event,

2. Query for the connection point container, and then find the

connection point for the event.

3. Hook up the instance of the event class (from step 1) to the connection point

 

hope this helps

vbrevised.zip

Edited December 21, 2005 by PlausiblyDamp

[vsdotnetguy]

I meant Laura versus Lauru...my bad

[vsdotnetguy]

BTW...You must include the method signature code for each of the document event methods because the winform must now implement the mshtml.HTMLDocumentEvents2 interface

[bgerby]

vsdotnetguy,

 

Thank you so much. That works perfectly. I thought I had tried everything, but I guess not. Hope I can return the favor.

[bgerby]

Events being called as many times as pages loaded

 

I have a strange issue now. If I load one page, I can capture event such as a click or a an onkeydown. Only 1 event is fired. But, if I load one page after another (I am calling Me.AxWebBrowser1.Navigate2(strUrl) where strUrl is the url to load a new page), the new document loads, but now all of my events are doubled. So, if i capture the onclick event, it acts as if it is clicking on the new document and the old document. If I load 10 pages, I get 10 events. It is as if I need to dispose of the first document before I load a new one. But, I have tried a number of things and cannot get the original document to be gone so I only have 1 event. Is Navigate2 the wrong function to load a document? I have tried Navigate.

 

vsdotnet or other

To see an example of this, add "AxWebBrowser1.GoHome()" to the onclick event of the sample vsdotnet posted. You will see now the listbox starts to exponentially add more items.

 

Gotta love this stuff. I am sure there is an easy solution, but not easy for me I guess.

 

Thanks in advance.

[bgerby]

I actually solved my last issue on my own. I'm not sure how good a fix it is, but it works. I set a global boolean variable that tells me whether to do the UCOMIConnectionPointContainer stuff in the AxWebBrowser1_DocumentComplete function. Once, I load the first doc, I change the boolean variable so I only do it once and that seems to work. It actually makes senses to me now too. If this seems off-base, let me know.

[maxter]

Well we can capture click events, but in a HTML document there are forms, inputs, textareas, .... and if I want capture change events of several html components like inputs areas, textareas,...

I've thinking about:

 

- parse html document to extract each html control and add a eventhandler for it, is it possible??

 

or

 

- wait until web page go to next page, but before capture the state of all html controls.

 

Because i want record user actions over web pages. And after play user actions recorded automatically.

 

Can u help me???

 

Thanks so much.

[chandra]

hi i have tried this examples but focus is not going to textbox and push ing of buttons not coming. i get the events why it happening?

[cutiti]

Hi , I experienced similar problems too that all other events are ignored if I tried to catch one specific event, such as click or double-click. Did anyone have an answer to this?

 

Many thanks.

Kim.

[bkpsu]

wow, I've spent a whole week trying to figure out what I was doing wrong and why my browser window wasn't getting the focus back after a click event. I even followed MSDN examples to the "T". Then, I found this site and fixed my problem in 5 mins, thanks!!! :-D

[Drapondur]

Hello everybody,

 

I think there's a mistake in the code with this UCOMIConnectionPointContainer stuff.

I guess it is is in Sub Dispose:

 

Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
       If disposing Then
           If Not (components Is Nothing) Then
               components.Dispose()
               If cookie = -1 Then '!!! THINK it mst be: If cookie <> -1 then ...
                   icp.Unadvise(cookie)
               Else
                   cookie = -1

               End If
           End If
       End If
       MyBase.Dispose(disposing)
   End Sub

 

Since i don't know exactly what all this UCOMIConnectionPoint-ing means I am not sure if it's really a mistake.

 

Bye

D.

[jasonboland]

Sorry to dig up old threads, but was anyone able to resolve the other events not firing problem?

[dynamic_sysop]

yes :) i've done a bit there , for C# .....

       public SHDocVw.WebBrowser_V1 ie;// this will handle the events that dont normally trigger.
	
	private void Form1_Load(object sender, System.EventArgs e)
	{
		ie=(SHDocVw.WebBrowser_V1)this.axWebBrowser1.Application;
		this.ie.BeforeNavigate+=new SHDocVw.DWebBrowserEvents_BeforeNavigateEventHandler(this.ie_BeforeNavigate);
		this.ie.NewWindow+=new SHDocVw.DWebBrowserEvents_NewWindowEventHandler(this.ie_NewWindow);
		object o=null;
		axWebBrowser1.Navigate("http://google.com",ref o,ref o,ref o,ref o);
	}

	private void ie_BeforeNavigate(string URL,int Flags, string TargetFrameName,ref object PostData, string Headers, ref bool Cancel)
	{
		MessageBox.Show("you are about to navigate to...\n" + URL);
	}
	private void ie_NewWindow(string URL,int Flags, string TargetFrameName,ref object PostData, string Headers, ref bool Cancel)
	{
           MessageBox.Show("a new window is trying to open, the url is...\n" + URL);
	}

	private void button1_Click(object sender, System.EventArgs e)
	{
		object o=null;
		axWebBrowser1.Navigate("http://www.autotrader.co.uk",ref o,ref o,ref o,ref o);
	}

an article i posted a long time ago on the codeproject for vb.net...

Extending the axWebbrowser control events.

basically like this...

   Private WithEvents doc As SHDocVw.DWebBrowserEvents_Event 
    '/// doc will handle all the events for brweb now... 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load 
        Dim b As Object = brWeb.Application 
        doc = DirectCast(b, SHDocVw.WebBrowser_V1) '///set doc as the active handler for brweb's events. 
    End Sub 
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click 
        brWeb.Navigate("http://google.com") '///lets navigate to a website. 
    End Sub 
 
    Private Sub doc_BeforeNavigate(ByVal URL As String, ByVal Flags As Integer, ByVal TargetFrameName As String, ByRef PostData As Object, ByVal Headers As String, ByRef Cancel As Boolean) Handles doc.BeforeNavigate 
        MessageBox.Show(URL) '/// check that before navigate now works. 
    End Sub 
 
    Private Sub doc_StatusTextChange(ByVal [Text] As String) Handles doc.StatusTextChange 
        Label1.Text = Text '///show the status text in a label. 
    End Sub 
 
    Private Sub doc_TitleChange(ByVal [Text] As String) Handles doc.TitleChange 
        MyBase.Text = Text '/// set the form's caption to the current url 
    End Sub 

maybe these could go in the code section of this forum?

[jtal]

Yes, but what about the GUI?

 

Capturing events is something that I've also been working on. Using the Web Browser control is great for changing an application layout, or as a natural interface when dealing with xml-based data, but...

 

I'd like to "tweak" the control itself. Specifically, I'd like the control to be displayed flat instead of as Fixed3d. Any ideas? I can't seem to find anyone else that cares. :)