WebBrowser.CreateSink Method
Definition
Important
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Associates the underlying ActiveX control with a client that can handle control events.
protected:
override void CreateSink();protected override void CreateSink ();override this.CreateSink : unit -> unitProtected Overrides Sub CreateSink ()Examples
The following code example illustrates the use of this method in a class derived from WebBrowser that supplements the normal WebBrowser events with the NavigateError event from the OLE DWebBrowserEvents2 interface.
using System;
using System.Windows.Forms;
using System.Runtime.InteropServices;
using System.Security.Permissions;
namespace WebBrowserExtensibility
{
public class Form1 : Form
{
[STAThread]
public static void Main()
{
Application.Run(new Form1());
}
private WebBrowser2 wb = new WebBrowser2();
public Form1()
{
wb.Dock = DockStyle.Fill;
wb.NavigateError += new
WebBrowserNavigateErrorEventHandler(wb_NavigateError);
Controls.Add(wb);
// Attempt to navigate to an invalid address.
wb.Navigate("www.widgets.microsoft.com");
}
private void wb_NavigateError(
object sender, WebBrowserNavigateErrorEventArgs e)
{
// Display an error message to the user.
MessageBox.Show("Cannot navigate to " + e.Url);
}
}
public class WebBrowser2 : WebBrowser
{
AxHost.ConnectionPointCookie cookie;
WebBrowser2EventHelper helper;
protected override void CreateSink()
{
base.CreateSink();
// Create an instance of the client that will handle the event
// and associate it with the underlying ActiveX control.
helper = new WebBrowser2EventHelper(this);
cookie = new AxHost.ConnectionPointCookie(
this.ActiveXInstance, helper, typeof(DWebBrowserEvents2));
}
protected override void DetachSink()
{
// Disconnect the client that handles the event
// from the underlying ActiveX control.
if (cookie != null)
{
cookie.Disconnect();
cookie = null;
}
base.DetachSink();
}
public event WebBrowserNavigateErrorEventHandler NavigateError;
// Raises the NavigateError event.
protected virtual void OnNavigateError(
WebBrowserNavigateErrorEventArgs e)
{
if (this.NavigateError != null)
{
this.NavigateError(this, e);
}
}
// Handles the NavigateError event from the underlying ActiveX
// control by raising the NavigateError event defined in this class.
private class WebBrowser2EventHelper :
StandardOleMarshalObject, DWebBrowserEvents2
{
private WebBrowser2 parent;
public WebBrowser2EventHelper(WebBrowser2 parent)
{
this.parent = parent;
}
public void NavigateError(object pDisp, ref object url,
ref object frame, ref object statusCode, ref bool cancel)
{
// Raise the NavigateError event.
this.parent.OnNavigateError(
new WebBrowserNavigateErrorEventArgs(
(String)url, (String)frame, (Int32)statusCode, cancel));
}
}
}
// Represents the method that will handle the WebBrowser2.NavigateError event.
public delegate void WebBrowserNavigateErrorEventHandler(object sender,
WebBrowserNavigateErrorEventArgs e);
// Provides data for the WebBrowser2.NavigateError event.
public class WebBrowserNavigateErrorEventArgs : EventArgs
{
private String urlValue;
private String frameValue;
private Int32 statusCodeValue;
private Boolean cancelValue;
public WebBrowserNavigateErrorEventArgs(
String url, String frame, Int32 statusCode, Boolean cancel)
{
urlValue = url;
frameValue = frame;
statusCodeValue = statusCode;
cancelValue = cancel;
}
public String Url
{
get { return urlValue; }
set { urlValue = value; }
}
public String Frame
{
get { return frameValue; }
set { frameValue = value; }
}
public Int32 StatusCode
{
get { return statusCodeValue; }
set { statusCodeValue = value; }
}
public Boolean Cancel
{
get { return cancelValue; }
set { cancelValue = value; }
}
}
// Imports the NavigateError method from the OLE DWebBrowserEvents2
// interface.
[ComImport, Guid("34A715A0-6587-11D0-924A-0020AFC7AC4D"),
InterfaceType(ComInterfaceType.InterfaceIsIDispatch),
TypeLibType(TypeLibTypeFlags.FHidden)]
public interface DWebBrowserEvents2
{
[DispId(271)]
void NavigateError(
[In, MarshalAs(UnmanagedType.IDispatch)] object pDisp,
[In] ref object URL, [In] ref object frame,
[In] ref object statusCode, [In, Out] ref bool cancel);
}
}
Imports System.Windows.Forms
Imports System.Runtime.InteropServices
Imports System.Security.Permissions
Namespace WebBrowserExtensibility
<PermissionSetAttribute(SecurityAction.Demand, Name:="FullTrust")> _
Public Class Form1
Inherits Form
<STAThreadAttribute()> Public Shared Sub Main()
Application.Run(New Form1())
End Sub
Private WithEvents wb As New WebBrowser2()
Public Sub New()
wb.Dock = DockStyle.Fill
Controls.Add(wb)
' Attempt to navigate to an invalid address.
wb.Navigate("www.widgets.microsoft.com")
End Sub
Private Sub wb_NavigateError( _
ByVal sender As Object, _
ByVal e As WebBrowserNavigateErrorEventArgs) _
Handles wb.NavigateError
' Display an error message to the user.
MessageBox.Show("Cannot navigate to " + e.Url)
End Sub
End Class
Public Class WebBrowser2
Inherits WebBrowser
Private cookie As AxHost.ConnectionPointCookie
Private helper As WebBrowser2EventHelper
<PermissionSetAttribute(SecurityAction.LinkDemand, _
Name := "FullTrust")> Protected Overrides Sub CreateSink()
MyBase.CreateSink()
' Create an instance of the client that will handle the event
' and associate it with the underlying ActiveX control.
helper = New WebBrowser2EventHelper(Me)
cookie = New AxHost.ConnectionPointCookie( _
Me.ActiveXInstance, helper, GetType(DWebBrowserEvents2))
End Sub
<PermissionSetAttribute(SecurityAction.LinkDemand, _
Name := "FullTrust")> Protected Overrides Sub DetachSink()
' Disconnect the client that handles the event
' from the underlying ActiveX control.
If cookie IsNot Nothing Then
cookie.Disconnect()
cookie = Nothing
End If
MyBase.DetachSink()
End Sub
Public Event NavigateError As WebBrowserNavigateErrorEventHandler
' Raises the NavigateError event.
Protected Overridable Sub OnNavigateError( _
ByVal e As WebBrowserNavigateErrorEventArgs)
RaiseEvent NavigateError(Me, e)
End Sub
' Handles the NavigateError event from the underlying ActiveX
' control by raising the NavigateError event defined in this class.
Private Class WebBrowser2EventHelper
Inherits StandardOleMarshalObject
Implements DWebBrowserEvents2
Private parent As WebBrowser2
Public Sub New(ByVal parent As WebBrowser2)
Me.parent = parent
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 DWebBrowserEvents2.NavigateError
' Raise the NavigateError event.
Me.parent.OnNavigateError( _
New WebBrowserNavigateErrorEventArgs( _
CStr(URL), CStr(frame), CInt(statusCode), cancel))
End Sub
End Class
End Class
' Represents the method that will handle the WebBrowser2.NavigateError event.
Public Delegate Sub WebBrowserNavigateErrorEventHandler(ByVal sender As Object, _
ByVal e As WebBrowserNavigateErrorEventArgs)
' Provides data for the WebBrowser2.NavigateError event.
Public Class WebBrowserNavigateErrorEventArgs
Inherits EventArgs
Private urlValue As String
Private frameValue As String
Private statusCodeValue As Int32
Private cancelValue As Boolean
Public Sub New( _
ByVal url As String, ByVal frame As String, _
ByVal statusCode As Int32, ByVal cancel As Boolean)
Me.urlValue = url
Me.frameValue = frame
Me.statusCodeValue = statusCode
Me.cancelValue = cancel
End Sub
Public Property Url() As String
Get
Return urlValue
End Get
Set(ByVal value As String)
urlValue = value
End Set
End Property
Public Property Frame() As String
Get
Return frameValue
End Get
Set(ByVal value As String)
frameValue = value
End Set
End Property
Public Property StatusCode() As Int32
Get
Return statusCodeValue
End Get
Set(ByVal value As Int32)
statusCodeValue = value
End Set
End Property
Public Property Cancel() As Boolean
Get
Return cancelValue
End Get
Set(ByVal value As Boolean)
cancelValue = value
End Set
End Property
End Class
' Imports the NavigateError method from the OLE DWebBrowserEvents2
' interface.
<ComImport(), Guid("34A715A0-6587-11D0-924A-0020AFC7AC4D"), _
InterfaceType(ComInterfaceType.InterfaceIsIDispatch), _
TypeLibType(TypeLibTypeFlags.FHidden)> _
Public Interface DWebBrowserEvents2
<DispId(271)> Sub NavigateError( _
<InAttribute(), MarshalAs(UnmanagedType.IDispatch)> _
ByVal pDisp As Object, _
<InAttribute()> ByRef URL As Object, _
<InAttribute()> ByRef frame As Object, _
<InAttribute()> ByRef statusCode As Object, _
<InAttribute(), OutAttribute()> ByRef cancel As Boolean)
End Interface
End Namespace
Remarks
This method is useful if you are familiar with OLE development using the unmanaged WebBrowser ActiveX control and you want to extend the functionality of the Windows Forms WebBrowser control, which is a managed wrapper for the ActiveX control. You can use this extensibility to implement events from the ActiveX control that are not provided by the wrapper control.
Applies to
See also
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