在Windows Phone 8.1上退出GridView的重新排序模式时发生的事件

Question

I am creating a WinRT-flavored Windows Phone 8.1 app. It uses a GridView to show many tiles that users can tap to execute commands. Users can also hold a tile to enter ReorderMode for the GridView . I enable reordering when the user holds a tile by setting ReorderMode . Since each tile contains a button with a command bound to it, I also set IsEnabled = false for the button in each tile. This allows the user to reorder tiles without triggering commands.

My problem is re-enabling the button in each tile when the user exits ReorderMode . By default, a user can tap the back button to exit ReorderMode , but I have not found any event to listen to. Is there an event that fires when ReorderMode is disabled that I can listen for to re-enable the button in each tile? Subscribing to HardwareButtons.BackPressed does not work.

Answer 1

Subscribing to the back button doesn't work as the GridView eats that event before you see it. You have to bind to ReorderMode: ReorderMode="{Binding ReorderProperty, Mode=TwoWay}"

Then in the ReorderProperty setter, have code that handles the change.

Answer 2

I've came across this problem recently and my solution for reordering items with drag and drop with nice user experience was to:

1. Enable dragging when GridView item is double-tapped:

private void GridView_DoubleTapped(object sender, DoubleTappedRoutedEventArgs e)
        {
            if (sender is GridView)
            {
                (sender as GridView).ReorderMode = ListViewReorderMode.Enabled;
            }
        }

2. Disable reordering when Grid looses focus:

private void GridView_LostFocus(object sender, RoutedEventArgs e)
            {
                if (sender is GridView)
                {
                    (sender as GridView).ReorderMode = ListViewReorderMode.Disabled;
                }
            }

My grid view XAML code was:

<GridView  
ItemsSource="{Binding MyObservableCollection}" 
AllowDrop="True"    
CanDragItems="True" 
CanReorderItems="True" 
DoubleTapped="GridView_DoubleTapped" 
LostFocus="GridView_LostFocus" >

Of course it is a solution for Windows Phone 8.1 GridView .