MVVM中的Webbrowser LoadCompleted事件

Question

首先，在我的Page1控件中声明的变量：private PPt.Presentation oPPPresentation = null;    private PPt.Application oPPApplication = null;    private PPt.SlideShowWindow oPPslideShow;    private PPt.Slide oPPSlide;    private Object oDocument;我目前有一个webBrowser控件（称为powerPointBrowser1），该控件显示通过字符串传递的PowerPoint：public Page1()    {        InitializeComponent();        powerPointBrowser1.Navigate(strFileName);        powerPointBrowser1.LoadCompleted += powerPointBrowser1_LoadCompleted;    }这是我的powerPoint1Browser_LoadCompleted方法：private void powerPointBrowser1_LoadCompleted(object sender, NavigationEventArgs e)    {        oDocument = powerPointBrowser1.Document;        oPPPresentation = (PPt.Presentation)oDocument;        oPPApplication = oPPPresentation.Application;    }现在我的问题是：如何在Page1ViewModel中获取LoadCompleted方法，以便可以访问VM中的oDocument？