<ListBox x:Name="lbMailShots" ItemsSource="{Binding MessageOrderedList}" Grid.Row="1" ScrollViewer.HorizontalScrollBarVisibility="Disabled" >
                <i:Interaction.Triggers>
                    <i:EventTrigger EventName="SelectionChanged">
                        <i:InvokeCommandAction Command="{Binding EmailShotSelectionChangedCommand}" CommandParameter="{Binding ElementName=lbMailShots}" />
                    </i:EventTrigger>
                </i:Interaction.Triggers>
                <ListBox.ItemTemplate>
                    <ItemContainerTemplate>
                        <Grid>
                            <Grid.RowDefinitions>
                                <RowDefinition ></RowDefinition>
                                <RowDefinition ></RowDefinition>
                            </Grid.RowDefinitions>
                            <Grid.ColumnDefinitions>
                                <ColumnDefinition x:Name="cdMailShot"></ColumnDefinition>
                            </Grid.ColumnDefinitions>
                            <TextBlock x:Name="tbMailSubject" Grid.Row="0"  Text="{Binding Path=Subject}" TextTrimming="CharacterEllipsis" FontSize="14" Padding="0, 10, 0 0" TextWrapping="NoWrap"></TextBlock>
                            <TextBlock x:Name="tbMailBodyShot" Grid.Row="1"  Text="{Binding Path=BodyShot}" TextTrimming="CharacterEllipsis" FontSize="12" Foreground="#777" Padding="0, 0,0,10" TextWrapping="NoWrap"></TextBlock>
                        </Grid>
                    </ItemContainerTemplate>
                </ListBox.ItemTemplate>
            </ListBox>
<WebBrowser x:Name="wbMailBody"   />

private ICommand emailShotSelectionChangedCommand;
        public ICommand EmailShotSelectionChangedCommand
        {
            get
            {
                if (this.emailShotSelectionChangedCommand == null)
                    this.emailShotSelectionChangedCommand = new DelegateCommand(x => this.EmailShotSelectionChanged(x));

                return this.emailShotSelectionChangedCommand;
            }
        }

        private void EmailShotSelectionChanged(object o)
        {
            var listbox = o as ListBox;
            if (listbox.SelectedItem == null)
                return;

            var vodel = listbox.SelectedItem as MessageListBoxItemModel;
            var path = System.IO.Path.Combine(SystemConfiguration.Eml.Folder, vodel.EmlNameWithExtension);
            var msg = Mail_Message.ParseFromFile(path);

　　　　　　　// 这个wbMailBody 是个WebBrowser控件，在ViewModel类里看不到这个控件
　　　　　　　// 所以这行代码报错。请问MVVM怎么解决这样的问题

            this.wbMailBody.NavigateToString(msg.BodyHtmlText.WrapsWithHtmlTag());
        }