Added Cancel button in file properties (#1811)

Author: d2dyno1

Files/Views/Pages/Properties.xaml

@@ -67,11 +67,22 @@
             <Grid.ColumnDefinitions>
                 <ColumnDefinition Width="*" />
                 <ColumnDefinition Width="*" />
+                <ColumnDefinition Width="Auto" />
             </Grid.ColumnDefinitions>
+            <Button
+                x:Name="CancelButton"
+                x:Uid="PropertiesDialogCancelButton"
+                Grid.Column="1"
+                MinWidth="100"
+                HorizontalAlignment="Right"
+                Click="CancelButton_Click"
+                Content="Cancel"
+                Margin="0 0 10 0"
+                Style="{ThemeResource ButtonRevealStyle}" />
             <Button
                 x:Name="OKButton"
                 x:Uid="PropertiesDialogOKButton"
-                Grid.Column="1"
+                Grid.Column="2"
                 MinWidth="100"
                 HorizontalAlignment="Right"
                 Click="OKButton_Click"

Files/Views/Pages/Properties.xaml.cs

@@ -164,7 +164,7 @@ private async void OKButton_Click(object sender, RoutedEventArgs e)
         {
             if (contentFrame.Content is PropertiesGeneral)
             {
-                (contentFrame.Content as PropertiesGeneral).SaveChanges(listedItem);
+                await (contentFrame.Content as PropertiesGeneral).SaveChanges(listedItem);
             }
 
             if (ApiInformation.IsApiContractPresent("Windows.Foundation.UniversalApiContract", 8))
@@ -178,6 +178,19 @@ private async void OKButton_Click(object sender, RoutedEventArgs e)
             }
         }
 
+        private async void CancelButton_Click(object sender, RoutedEventArgs e)
+        {
+            if (ApiInformation.IsApiContractPresent("Windows.Foundation.UniversalApiContract", 8))
+            {
+                await ApplicationView.GetForCurrentView().TryConsolidateAsync();
+            }
+            else
+            {
+                var propertiesDialog = Interaction.FindParent<ContentDialog>(this);
+                propertiesDialog.Hide();
+            }
+        }
+
         private async void Page_KeyDown(object sender, KeyRoutedEventArgs e)
         {
             if (e.Key.Equals(VirtualKey.Escape))

Files/Views/Pages/PropertiesGeneral.xaml.cs

@@ -8,6 +8,7 @@
 using Windows.UI.Xaml.Navigation;
 using Windows.ApplicationModel.Core;
 using Microsoft.Toolkit.Uwp.Helpers;
+using System.Threading.Tasks;
 
 // Il modello di elemento Pagina vuota è documentato all'indirizzo https://go.microsoft.com/fwlink/?LinkId=234238
 
@@ -64,7 +65,7 @@ protected override void OnNavigatedTo(NavigationEventArgs e)
             base.OnNavigatedTo(e);
         }
 
-        public async void SaveChanges(ListedItem item)
+        public async Task SaveChanges(ListedItem item)
         {
             if (ViewModel.OriginalItemName != null)
             {