HtmlElementEventArgs 的 ToElement 得不到相应的HtmlElement元素

[hwmfly]

开发环境：vb.net 2005
想得到webbrowser中用户点击的超链接、按钮等元素
代码如下：
Private Sub WebBrowser1_DocumentCompleted(ByVal sender As Object, ByVal e As System.Windows.Forms.WebBrowserDocumentCompletedEventArgs)
AddHandler Me.WebBrowser1.Document.Click, New HtmlElementEventHandler(AddressOf Document_Click)
End Sub

Private Sub Document_Click(ByVal sender As Object, ByVal e As System.Windows.Forms.HtmlElementEventArgs)
' Insert your code here.
Dim ele As HtmlElement
Dim str As String = ""
ele = e.ToElement
'ele = Me.WebBrowser1.Document.GetElementFromPoint(e.MousePosition)
If ele IsNot Nothing Then
str = ele.InnerText
End If
MsgBox(str)
End Sub
我调试的时候发现ele为nothing,也就是说e.ToElement获取不成功，试了很多次都是同样的问题

http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=76921&SiteID=1

这个家伙也遇到同样的问题（不过他还没有知道真正的原因）

后来我改成
ele = Me.WebBrowser1.Document.GetElementFromPoint(e.MousePosition)

成功了，但是总觉得别扭。

那位高手知道其中的原因