.net里的webbrowser，怎么准确获取弹出窗口的网址，并在自己的新窗口中继承打开

Namespace LzmTW.uSystem.uWindows.uForms.Web
    <Docking(DockingBehavior.AutoDock), Designer("System.Windows.Forms.Design.WebBrowserDesigner, System.Design, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"), ClassInterface(ClassInterfaceType.AutoDispatch), DefaultEvent("DocumentCompleted"), ComVisible(True), DefaultProperty("Url")> _
    <System.Drawing.ToolboxBitmap(GetType(System.Windows.Forms.WebBrowser))> _
    Public Class WebBrowserEx
        Inherits System.Windows.Forms.WebBrowser

        Friend Const DefaultUri As String = "about:blank"
        Private WithEvents gComInternetExplorer As SHDocVw.InternetExplorer
        Private gCanNewWindow As Boolean = True

        Public Property CanNewWindow() As Boolean
            Get
                Return Me.gCanNewWindow
            End Get
            Set(ByVal value As Boolean)
                Me.gCanNewWindow = value
            End Set
        End Property


        Sub New()
            Me.Url = New System.Uri(DefaultUri, System.UriKind.Absolute)
        End Sub

        Private Sub WebBrowser_HandleCreated(ByVal sender As Object, ByVal e As System.EventArgs) _
        Handles Me.HandleCreated
            Me.gComInternetExplorer = CType(Me.ActiveXInstance, SHDocVw.InternetExplorer)
            With gStatusList
                .Add(SHDocVw.OLECMDID.OLECMDID_CUT, False)
                .Add(SHDocVw.OLECMDID.OLECMDID_COPY, False)
                .Add(SHDocVw.OLECMDID.OLECMDID_PASTE, False)
            End With

        End Sub

        ''按钮、状态栏的隐藏显示
        ''动作由菜单发出

        Public Event StatusBarVisibleChanged As EventHandler
        Public Event AddressBarVisibleChanged As EventHandler
        Public Event LinkBarVisibleChanged As EventHandler
        Public Event StandarBarVisibleChanged As EventHandler

        Private gStatusBarVisible As Boolean
        Private gAddressBarVisible As Boolean
        Private gLinkBarVisible As Boolean
        Private gStandarBarVisible As Boolean

        Public Property StatusBarVisible() As Boolean
            Get
                Return Me.gStatusBarVisible
            End Get
            Set(ByVal value As Boolean)
                If Me.gStatusBarVisible <> value Then
                    Me.gStatusBarVisible = value
                    RaiseEvent StatusBarVisibleChanged(Me, New EventArgs)
                End If
            End Set
        End Property

        Public Property AddressBarVisible() As Boolean
            Get
                Return Me.gAddressBarVisible
            End Get
            Set(ByVal value As Boolean)
                If Me.gAddressBarVisible <> value Then
                    Me.gAddressBarVisible = value
                    RaiseEvent AddressBarVisibleChanged(Me, New EventArgs)
                End If
            End Set
        End Property

        Public Property LinkBarVisible() As Boolean
            Get
                Return Me.gLinkBarVisible
            End Get
            Set(ByVal value As Boolean)
                If Me.gLinkBarVisible <> value Then
                    Me.gLinkBarVisible = value
                    RaiseEvent LinkBarVisibleChanged(Me, New EventArgs)
                End If
            End Set
        End Property

        Public Property StandarBarVisible() As Boolean
            Get
                Return Me.gStandarBarVisible
            End Get
            Set(ByVal value As Boolean)
                If Me.gStandarBarVisible <> value Then
                    Me.gStandarBarVisible = value
                    RaiseEvent StandarBarVisibleChanged(Me, New EventArgs)
                End If
            End Set
        End Property

        ''New Window
        Private gNewWindowUri As Uri = New Uri(DefaultUri)
        Public ReadOnly Property NewWindowUri() As Uri
            Get
                Return gNewWindowUri
            End Get
        End Property

        Protected Overrides Sub OnStatusTextChanged(ByVal e As System.EventArgs)
            If UrlHelper.Common.IsValidURL(Me.StatusText) Then
                gNewWindowUri = New Uri(Me.StatusText)
            End If

            MyBase.OnStatusTextChanged(e)
        End Sub

        Protected Overrides Sub OnNewWindow(ByVal e As System.ComponentModel.CancelEventArgs)
            Dim mElement As HtmlElement = Me.Document.ActiveElement
            Dim mHref As String = mElement.GetAttribute("href")
            If Not String.IsNullOrEmpty(mHref) Then
                gNewWindowUri = New Uri(mHref)
            End If

            If Not Me.CanNewWindow Then
                e.Cancel = True
                Me.Navigate(Me.NewWindowUri)
            Else
                MyBase.OnNewWindow(e)
            End If
        End Sub
    End Class
End Namespace