如何刷新Longlist选择器？

Question

这是我的xaml代码

<Grid>
                        <phone:LongListSelector Name="iList"  ItemsSource="{Binding}" Grid.Row="1">
                            <phone:LongListSelector.ItemTemplate>
                                <DataTemplate>

                                    <StackPanel Height="60">
                                        <Grid Height="50">

                                            <TextBlock 
                                                Grid.Column="0"
                                                TextWrapping="NoWrap"
                                                Text="{Binding Mail}"
                                                Foreground="Black"
                                                FontSize="25"
                                                Margin="0,0,43,10"/>
                                            <Button  Visibility="{Binding BtnVisible}"  Margin="411,-16,-21,2" BorderBrush="Transparent" Style="{StaticResource ButtonStyle1}">
                                                <Button.Background>
                                                    <ImageBrush  Stretch="Uniform" ImageSource="/Assets/Icons/InvitePlusIcon.png"/>
                                                </Button.Background>
                                            </Button>
                                            <CheckBox Content="CheckBox"
                                                   IsChecked="{Binding IsChecked,Mode=TwoWay}"
                                                   Visibility="{Binding CBVisible}"
                                                   Background="SkyBlue"
                                                   HorizontalAlignment="Left"
                                                   Margin="400,-13,0,-4"
                                                   VerticalAlignment="Top" Height="67" Width="53"/>

                                            <Border BorderBrush="#FFE0E0E0" BorderThickness="0 0 0 1" HorizontalAlignment="Left" Width="456" />

                                        </Grid>

                                    </StackPanel>
                                </DataTemplate>
                            </phone:LongListSelector.ItemTemplate>
                        </phone:LongListSelector>

                    </Grid>

[1]当我单击编辑应用程序栏按钮时。我需要页面刷新，我的复选框显示为true，按钮可见为假

[2]如何刷新长列表选择器？

[3]如何改变动态控制显示？

[4]检查我的xaml代码。这是否正确？

[5]有人告诉我吗？