How To Handle Document Events in a Visual Basic .NET Application (311284)


The information in this article applies to:

  • Microsoft Visual Basic .NET (2002)
  • Microsoft Visual Basic .NET (2003)
This article was previously published under Q311284
For a Microsoft Visual C# .NET version of this article, see 312777.

IN THIS TASK

SUMMARY

This article demonstrates how to catch document events for the WebBrowser control in Visual Basic .NET.

back to the top

Requirements

The following list outlines the recommended hardware, software, network infrastructure, and service packs that you need:
  • Microsoft Visual Studio .NET
  • Microsoft Internet Explorer 5.5 Service Pack 2 (SP2) or later
This article assumes that you are familiar with the following topics:
  • Visual Studio .NET
  • Internet Explorer
  • WebBrowser control
back to the top

Description of the Technique

The WebBrowser control is an easy control to work with in Visual Studio .NET or earlier versions of Microsoft Visual Studio. However, you may find it more difficult to handle the events of a WebBrowser control in Visual Studio .NET.

The following event interface exposes most of the document events that you handle in your application: 
Mshtml.HTMLDocumentEvents2_Event
To handle the event, you must create your own Sub procedure or function that you can call when the event occurs. You must match the signature of the event that fires. For example, the following Sub procedure handles the MouseOver event of the document: 
Private Sub document_onmouseover(ByVal e As mshtml.IHTMLEventObj)
After the event handler is in place, you must hook the event. You can hook an event any time after the DocumentComplete event on the WebBrowser control fires. Here is the syntax of the hook: 
AddHandler CType(document, _
mshtml.HTMLDocumentEvents2_Event).onmouseover, _
AddressOf Me.document_onmouseover
This code calls the AddHandler statement and uses the CType function to pass the event. The CType function casts the document object to the appropriate type (mshtml.HTMLDocumentEvents2_Event), and then the OnMouseOver event is passed from that. The Me.document_onmouseoverSub procedure is passed to the second parameter, the AddressOf statement, which provides the address of your handler.

back to the top

Create the Project and Add Code

In the following sample, the WebBrowser control browses to http://www.microsoft.com. After the page loads, the sample hooks the OnMouseOver and the OnClick events. The sample then adds text to a list box whenever the events fire.
  1. Start Visual Studio .NET.
  2. Create a new Windows Application project in Visual Basic .NET
  3. Add a reference to Microsoft.mshtml in the project.
  4. In the toolbox, click General.
  5. Right-click the open panel, and then click Customize Toolbox.
  6. Select the Microsoft Web Browser check box, and then click OK.
  7. In the toolbox, double-click Explorer.
  8. In the toolbox, click Windows Forms, and then double-click the ListBox control.
  9. Arrange the controls so that they are easy to view on the form.
  10. Add the following code to the top of AssemblyInfo.vb, replace the existing Import sentences 
    Imports System
Imports System.Drawing
Imports System.Collections
Imports System.ComponentModel
Imports System.Windows.Forms
Imports System.Data
Imports System.Reflection
Imports System.Runtime.InteropServices
Imports System.Threading
Imports System.Diagnostics
  11. Add the following code between Windows Form Designer generated code and End Class in the code view of Form1.vb Public 
    Shared dwCookie2 As Integer
    Public Sub add_list(ByVal a As Object)
        ListBox1.Items.Insert(0, a)
    End Sub
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        AxWebBrowser1.Navigate2("http://www.microsoft.com")
        Dim x As IEEvents = New IEEvents(AxWebBrowser1)
        x.fm = Me
    End Sub

    Private Sub AxWebBrowser1_Enter(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles AxWebBrowser1.Enter

    End Sub

    Private Sub AxWebBrowser1_DocumentComplete(ByVal sender As Object, ByVal e As AxSHDocVw.DWebBrowserEvents2_DocumentCompleteEvent) Handles AxWebBrowser1.DocumentComplete
        Dim doc As mshtml.HTMLDocument
        doc = AxWebBrowser1.Document

        AddHandler CType(doc, _
            mshtml.HTMLDocumentEvents2_Event).onclick, AddressOf Document_onclick
        AddHandler CType(doc, _
     mshtml.HTMLDocumentEvents2_Event).onmouseover, AddressOf Document_onmouseover
    End Sub

    Private Sub AxWebBrowser1_BeforeNavigate2(ByVal sender As Object, ByVal e As AxSHDocVw.DWebBrowserEvents2_BeforeNavigate2Event) Handles AxWebBrowser1.BeforeNavigate2
        Dim doc As mshtml.HTMLDocument
        doc = AxWebBrowser1.Document

        RemoveHandler CType(doc, _
            mshtml.HTMLDocumentEvents2_Event).onclick, _
            AddressOf Document_onclick
        RemoveHandler CType(doc, _
            mshtml.HTMLDocumentEvents2_Event).onmouseover, _
            AddressOf Document_onmouseover
    End Sub
    Private Sub Document_onmouseover(ByVal e As mshtml.IHTMLEventObj)
        ListBox1.Items.Insert(0, "onMouseOver: " & _
            e.srcElement.tagName.ToString())
    End Sub
    Private Function Document_onclick(ByVal e As mshtml.IHTMLEventObj) _
            As Boolean
        ListBox1.Items.Insert(0, "onClick: " & _
            e.srcElement.tagName.ToString())
        Return True
    End Function
  12. Add the following code after End Class
    Public Class IEHTMLDocumentEvents
    Implements mshtml.HTMLDocumentEvents2
    Public Sub onactivate(ByVal pEvtObj As mshtml.IHTMLEventObj) Implements mshtml.HTMLDocumentEvents2.onactivate

    End Sub

    Public Sub onafterupdate(ByVal pEvtObj As mshtml.IHTMLEventObj) Implements mshtml.HTMLDocumentEvents2.onafterupdate

    End Sub

    Public Function onbeforeactivate(ByVal pEvtObj As mshtml.IHTMLEventObj) As Boolean Implements mshtml.HTMLDocumentEvents2.onbeforeactivate
        Return True
    End Function

    Public Function onbeforedeactivate(ByVal pEvtObj As mshtml.IHTMLEventObj) As Boolean Implements mshtml.HTMLDocumentEvents2.onbeforedeactivate
        Return True
    End Function

    Public Sub onbeforeeditfocus(ByVal pEvtObj As mshtml.IHTMLEventObj) Implements mshtml.HTMLDocumentEvents2.onbeforeeditfocus

    End Sub

    Public Function onbeforeupdate(ByVal pEvtObj As mshtml.IHTMLEventObj) As Boolean Implements mshtml.HTMLDocumentEvents2.onbeforeupdate
        Return True
    End Function

    Public Sub oncellchange(ByVal pEvtObj As mshtml.IHTMLEventObj) Implements mshtml.HTMLDocumentEvents2.oncellchange

    End Sub

    Public Function onclick(ByVal pEvtObj As mshtml.IHTMLEventObj) As Boolean Implements mshtml.HTMLDocumentEvents2.onclick
        Return True
    End Function

    Public Function oncontextmenu(ByVal pEvtObj As mshtml.IHTMLEventObj) As Boolean Implements mshtml.HTMLDocumentEvents2.oncontextmenu
        Return True
    End Function

    Public Function oncontrolselect(ByVal pEvtObj As mshtml.IHTMLEventObj) As Boolean Implements mshtml.HTMLDocumentEvents2.oncontrolselect
        Return True
    End Function

    Public Sub ondataavailable(ByVal pEvtObj As mshtml.IHTMLEventObj) Implements mshtml.HTMLDocumentEvents2.ondataavailable

    End Sub

    Public Sub ondatasetchanged(ByVal pEvtObj As mshtml.IHTMLEventObj) Implements mshtml.HTMLDocumentEvents2.ondatasetchanged

    End Sub

    Public Sub ondatasetcomplete(ByVal pEvtObj As mshtml.IHTMLEventObj) Implements mshtml.HTMLDocumentEvents2.ondatasetcomplete

    End Sub

    Public Function ondblclick(ByVal pEvtObj As mshtml.IHTMLEventObj) As Boolean Implements mshtml.HTMLDocumentEvents2.ondblclick
        Return True
    End Function

    Public Sub ondeactivate(ByVal pEvtObj As mshtml.IHTMLEventObj) Implements mshtml.HTMLDocumentEvents2.ondeactivate

    End Sub

    Public Function ondragstart(ByVal pEvtObj As mshtml.IHTMLEventObj) As Boolean Implements mshtml.HTMLDocumentEvents2.ondragstart
        Return True
    End Function

    Public Function onerrorupdate(ByVal pEvtObj As mshtml.IHTMLEventObj) As Boolean Implements mshtml.HTMLDocumentEvents2.onerrorupdate
        Return True
    End Function

    Public Sub onfocusin(ByVal pEvtObj As mshtml.IHTMLEventObj) Implements mshtml.HTMLDocumentEvents2.onfocusin

    End Sub

    Public Sub onfocusout(ByVal pEvtObj As mshtml.IHTMLEventObj) Implements mshtml.HTMLDocumentEvents2.onfocusout

    End Sub

    Public Function onhelp(ByVal pEvtObj As mshtml.IHTMLEventObj) As Boolean Implements mshtml.HTMLDocumentEvents2.onhelp
        Return True
    End Function

    Public Sub onkeydown(ByVal pEvtObj As mshtml.IHTMLEventObj) Implements mshtml.HTMLDocumentEvents2.onkeydown

    End Sub

    Public Function onkeypress(ByVal pEvtObj As mshtml.IHTMLEventObj) As Boolean Implements mshtml.HTMLDocumentEvents2.onkeypress
        Return True
    End Function

    Public Sub onkeyup(ByVal pEvtObj As mshtml.IHTMLEventObj) Implements mshtml.HTMLDocumentEvents2.onkeyup

    End Sub

    Public Sub onmousedown(ByVal pEvtObj As mshtml.IHTMLEventObj) Implements mshtml.HTMLDocumentEvents2.onmousedown

    End Sub

    Public Sub onmousemove(ByVal pEvtObj As mshtml.IHTMLEventObj) Implements mshtml.HTMLDocumentEvents2.onmousemove

    End Sub

    Public Sub onmouseout(ByVal pEvtObj As mshtml.IHTMLEventObj) Implements mshtml.HTMLDocumentEvents2.onmouseout

    End Sub

    Public Sub onmouseover(ByVal pEvtObj As mshtml.IHTMLEventObj) Implements mshtml.HTMLDocumentEvents2.onmouseover

    End Sub

    Public Sub onmouseup(ByVal pEvtObj As mshtml.IHTMLEventObj) Implements mshtml.HTMLDocumentEvents2.onmouseup

    End Sub

    Public Function onmousewheel(ByVal pEvtObj As mshtml.IHTMLEventObj) As Boolean Implements mshtml.HTMLDocumentEvents2.onmousewheel
        Return True
    End Function

    Public Sub onpropertychange(ByVal pEvtObj As mshtml.IHTMLEventObj) Implements mshtml.HTMLDocumentEvents2.onpropertychange

    End Sub

    Public Sub onreadystatechange(ByVal pEvtObj As mshtml.IHTMLEventObj) Implements mshtml.HTMLDocumentEvents2.onreadystatechange

    End Sub

    Public Sub onrowenter(ByVal pEvtObj As mshtml.IHTMLEventObj) Implements mshtml.HTMLDocumentEvents2.onrowenter

    End Sub

    Public Function onrowexit(ByVal pEvtObj As mshtml.IHTMLEventObj) As Boolean Implements mshtml.HTMLDocumentEvents2.onrowexit
        Return True
    End Function

    Public Sub onrowsdelete(ByVal pEvtObj As mshtml.IHTMLEventObj) Implements mshtml.HTMLDocumentEvents2.onrowsdelete

    End Sub

    Public Sub onrowsinserted(ByVal pEvtObj As mshtml.IHTMLEventObj) Implements mshtml.HTMLDocumentEvents2.onrowsinserted

    End Sub

    Public Sub onselectionchange(ByVal pEvtObj As mshtml.IHTMLEventObj) Implements mshtml.HTMLDocumentEvents2.onselectionchange

    End Sub

    Public Function onselectstart(ByVal pEvtObj As mshtml.IHTMLEventObj) As Boolean Implements mshtml.HTMLDocumentEvents2.onselectstart
        Return True
    End Function

    Public Function onstop(ByVal pEvtObj As mshtml.IHTMLEventObj) As Boolean Implements mshtml.HTMLDocumentEvents2.onstop
        Return True
    End Function
End Class

Public Class IEEvents
    Implements SHDocVw.DWebBrowserEvents2
    Public fm As Form1
    Private icp As System.Runtime.InteropServices.UCOMIConnectionPoint
    Private cookie As Integer = -1
    Private m_ie As AxSHDocVw.AxWebBrowser

    Public Sub New(ByRef ie As AxSHDocVw.AxWebBrowser)
        ' Call QueryInterface for IConnectionPointContainer
        m_ie = ie
        Dim icpc As System.Runtime.InteropServices.UCOMIConnectionPointContainer = CType(ie.GetOcx(), System.Runtime.InteropServices.UCOMIConnectionPointContainer)
        ' Find the connection point for the
        ' DWebBrowserEvents2 source interface
        Dim g As Guid = GetType(SHDocVw.DWebBrowserEvents2).GUID
        icpc.FindConnectionPoint(g, icp)

        'Pass a pointer to the host to the connection point
        icp.Advise(Me, cookie)

        ' Show the browser
        ie.Visible = True
        Dim oURL As Object = "http://www.microsoft.com"
        Dim oEmpty As Object = ""
        ie.Navigate2(oURL, oEmpty, oEmpty, oEmpty, oEmpty)

    End Sub


    Public Sub BeforeNavigate2(ByVal pDisp As Object, ByRef URL As Object, ByRef Flags As Object, ByRef TargetFrameName As Object, ByRef PostData As Object, ByRef Headers As Object, ByRef Cancel As Boolean) Implements SHDocVw.DWebBrowserEvents2.BeforeNavigate2

    End Sub

    Public Sub ClientToHostWindow(ByRef CX As Integer, ByRef CY As Integer) Implements SHDocVw.DWebBrowserEvents2.ClientToHostWindow

    End Sub

    Public Sub CommandStateChange(ByVal Command As Integer, ByVal Enable As Boolean) Implements SHDocVw.DWebBrowserEvents2.CommandStateChange

    End Sub

    Public Sub DocumentComplete(ByVal pDisp As Object, ByRef URL As Object) Implements SHDocVw.DWebBrowserEvents2.DocumentComplete
        Dim doc As mshtml.HTMLDocument = CType(CType(pDisp, SHDocVw.IWebBrowser2).Document, mshtml.HTMLDocument)
        Dim pConPtCon As System.Runtime.InteropServices.UCOMIConnectionPointContainer = CType(doc, System.Runtime.InteropServices.UCOMIConnectionPointContainer)
        Dim guid As Guid = System.Type.GetType("mshtml.HTMLDocumentEvents2").GUID
        Dim pConPt As System.Runtime.InteropServices.UCOMIConnectionPoint
        pConPtCon.FindConnectionPoint(guid, pConPt)
        Dim d As IEHTMLDocumentEvents = New IEHTMLDocumentEvents
        pConPt.Advise(d, Form1.dwCookie2)

        Dim iEvent As mshtml.HTMLDocumentEvents2_Event
        iEvent = CType(doc, mshtml.HTMLDocumentEvents2_Event)
        AddHandler iEvent.onclick, AddressOf ClickEventHandler
        AddHandler iEvent.onmouseover, AddressOf MouseOverEventHandler
    End Sub
    Private Function ClickEventHandler(ByVal e As mshtml.IHTMLEventObj) As Boolean
        fm.add_list(e.type + ":" + e.srcElement.tagName)
        Return True
    End Function
    Private Sub MouseOverEventHandler(ByVal e As mshtml.IHTMLEventObj)
        fm.add_list(e.type + ":" + e.srcElement.tagName)
    End Sub
    Public Sub DownloadBegin() Implements SHDocVw.DWebBrowserEvents2.DownloadBegin

    End Sub

    Public Sub DownloadComplete() Implements SHDocVw.DWebBrowserEvents2.DownloadComplete

    End Sub

    Public Sub FileDownload(ByRef Cancel As Boolean) Implements SHDocVw.DWebBrowserEvents2.FileDownload

    End Sub

    Public Sub NavigateComplete2(ByVal pDisp As Object, ByRef URL As Object) Implements SHDocVw.DWebBrowserEvents2.NavigateComplete2

    End Sub

    Public Sub NavigateError(ByVal pDisp As Object, ByRef URL As Object, ByRef Frame As Object, ByRef StatusCode As Object, ByRef Cancel As Boolean) Implements SHDocVw.DWebBrowserEvents2.NavigateError

    End Sub

    Public Sub NewWindow2(ByRef ppDisp As Object, ByRef Cancel As Boolean) Implements SHDocVw.DWebBrowserEvents2.NewWindow2

    End Sub

    Public Sub OnFullScreen(ByVal FullScreen As Boolean) Implements SHDocVw.DWebBrowserEvents2.OnFullScreen

    End Sub

    Public Sub OnMenuBar(ByVal MenuBar As Boolean) Implements SHDocVw.DWebBrowserEvents2.OnMenuBar

    End Sub

    Public Sub OnQuit() Implements SHDocVw.DWebBrowserEvents2.OnQuit

    End Sub

    Public Sub OnStatusBar(ByVal StatusBar As Boolean) Implements SHDocVw.DWebBrowserEvents2.OnStatusBar

    End Sub

    Public Sub OnTheaterMode(ByVal TheaterMode As Boolean) Implements SHDocVw.DWebBrowserEvents2.OnTheaterMode

    End Sub

    Public Sub OnToolBar(ByVal ToolBar As Boolean) Implements SHDocVw.DWebBrowserEvents2.OnToolBar

    End Sub

    Public Sub OnVisible(ByVal Visible As Boolean) Implements SHDocVw.DWebBrowserEvents2.OnVisible

    End Sub

    Public Sub PrintTemplateInstantiation(ByVal pDisp As Object) Implements SHDocVw.DWebBrowserEvents2.PrintTemplateInstantiation

    End Sub

    Public Sub PrintTemplateTeardown(ByVal pDisp As Object) Implements SHDocVw.DWebBrowserEvents2.PrintTemplateTeardown

    End Sub

    Public Sub PrivacyImpactedStateChange(ByVal bImpacted As Boolean) Implements SHDocVw.DWebBrowserEvents2.PrivacyImpactedStateChange

    End Sub

    Public Sub ProgressChange(ByVal Progress As Integer, ByVal ProgressMax As Integer) Implements SHDocVw.DWebBrowserEvents2.ProgressChange

    End Sub

    Public Sub PropertyChange(ByVal szProperty As String) Implements SHDocVw.DWebBrowserEvents2.PropertyChange

    End Sub

    Public Sub SetSecureLockIcon(ByVal SecureLockIcon As Integer) Implements SHDocVw.DWebBrowserEvents2.SetSecureLockIcon

    End Sub

    Public Sub StatusTextChange(ByVal Text As String) Implements SHDocVw.DWebBrowserEvents2.StatusTextChange

    End Sub

    Public Sub TitleChange(ByVal Text As String) Implements SHDocVw.DWebBrowserEvents2.TitleChange

    End Sub

    Public Sub UpdatePageStatus(ByVal pDisp As Object, ByRef nPage As Object, ByRef fDone As Object) Implements SHDocVw.DWebBrowserEvents2.UpdatePageStatus

    End Sub

    Public Sub WindowClosing(ByVal IsChildWindow As Boolean, ByRef Cancel As Boolean) Implements SHDocVw.DWebBrowserEvents2.WindowClosing

    End Sub

    Public Sub WindowSetHeight(ByVal Height As Integer) Implements SHDocVw.DWebBrowserEvents2.WindowSetHeight

    End Sub

    Public Sub WindowSetLeft(ByVal Left As Integer) Implements SHDocVw.DWebBrowserEvents2.WindowSetLeft

    End Sub

    Public Sub WindowSetResizable(ByVal Resizable As Boolean) Implements SHDocVw.DWebBrowserEvents2.WindowSetResizable

    End Sub

    Public Sub WindowSetTop(ByVal Top As Integer) Implements SHDocVw.DWebBrowserEvents2.WindowSetTop

    End Sub

    Public Sub WindowSetWidth(ByVal Width As Integer) Implements SHDocVw.DWebBrowserEvents2.WindowSetWidth

    End Sub
End Class
back to the top

Additional Notes

  • This process is the same if you automate Internet Explorer. Replace AxWebBrowser1 with your local variable name for Internet Explorer.
  • This sample does not consider framesets. When you navigate to a frameset, you may not see any events in your application. If necessary in your application, you must add code to handle the frameset possibility.
back to the top

REFERENCES

For more information about the WebBrowser control, as well as the methods, the properties, and the events that the WebBrowser control exposes, refer to the following MSDN documentation:

http://msdn.microsoft.com/library/default.asp?url=/workshop/browser/webbrowser/RefList_VB.asp

For more information about developing Web-based solutions for Microsoft Internet Explorer, visit the following Microsoft Web sites:

http://msdn.microsoft.com/ie/

http://support.microsoft.com/iep

back to the top
Modification Type:MajorLast Reviewed:4/21/2006
Keywords:kbHOWTOmaster kbWebBrowser KB311284 kbAudDeveloper
©2004 Microsoft Corporation. All rights reserved.