C#实现win10 uwp 右击浮出窗在点击位置

<ListView ItemsSource="{x:Bind View.Str}">
<ListView.ItemContainerStyle>
<Style TargetType="ListViewItem">
<Setter Property="HorizontalContentAlignment"
Value="Stretch" />
<Setter Property="VerticalContentAlignment" Value="Center"></Setter>
</Style>
</ListView.ItemContainerStyle>
<ListView.ItemTemplate>
<DataTemplate>
<Grid Background="#FFda2a5c" RightTapped="GridColection_OnRightTapped">
<TextBlock Text="{Binding}"></TextBlock>
</Grid>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>

private void GridColection_OnRightTapped(object sender, RightTappedRoutedEventArgs e)
{
MenuFlyout myFlyout = new MenuFlyout();
MenuFlyoutItem firstItem = new MenuFlyoutItem { Text = "OneIt" };
MenuFlyoutItem secondItem = new MenuFlyoutItem { Text = "TwoIt" };
myFlyout.Items.Add(firstItem);
myFlyout.Items.Add(secondItem);
//if you only want to show in left or buttom 
//myFlyout.Placement = FlyoutPlacementMode.Left;
FrameworkElement senderElement = sender as FrameworkElement;
//the code can show the flyout in your mouse click 
myFlyout.ShowAt(sender as UIElement, e.GetPosition(sender as UIElement));
}