版面列表自动翻页

BoardPage.xaml

@@ -15,13 +15,13 @@
     mc:Ignorable="d" d:DesignHeight="696" d:DesignWidth="480"
     d:DataContext="{d:DesignData SampleData/CurrentBoardViewModelSampleData.xaml}"
     shell:SystemTray.IsVisible="True"
-    shell:SystemTray.Opacity="{Binding IsLoaded, Converter={StaticResource LoadedOpacityConerter}}"
+    shell:SystemTray.Opacity="{Binding IsLoading, Converter={StaticResource LoadedOpacityConerter}, ConverterParameter=true}"
     toolkit:TiltEffect.IsTiltEnabled="True">
 
     <shell:SystemTray.ProgressIndicator>
         <shell:ProgressIndicator Text="载入中..."
-            IsVisible="{Binding IsLoaded, Converter={StaticResource BoolReverseConverter}}"
-            IsIndeterminate="{Binding IsLoaded, Converter={StaticResource BoolReverseConverter}}"/>
+            IsVisible="{Binding IsLoading}"
+            IsIndeterminate="{Binding IsLoading}"/>
     </shell:SystemTray.ProgressIndicator>
 
     <toolkit:TransitionService.NavigationInTransition>
@@ -60,16 +60,16 @@
         </StackPanel>
 
         <!--ContentPanel - place additional content here-->
-        <local:ExtendedListBox ItemsSource="{Binding Topics}" ItemTemplate="{StaticResource TopicDataTemplate}"
-                               SelectionChanged="Topic_Selected"
+        <local:ExtendedListBox x:Name="TopicsList" ItemsSource="{Binding Topics}" ItemTemplate="{StaticResource TopicDataTemplate}"
+                               SelectionChanged="TopicsList_Selected"
+                               NextPage="TopicsList_NextPage"
                                Grid.Row="1" Margin="12,0,12,0">
             <local:ExtendedListBox.ItemContainerStyle>
                 <Style TargetType="ListBoxItem">
                     <Setter Property="HorizontalContentAlignment" Value="Stretch"/>
                 </Style>
             </local:ExtendedListBox.ItemContainerStyle>
         </local:ExtendedListBox>
-        <Button Grid.Row="2" Visibility="Collapsed" Margin="-12 0" x:Name="LoadMore" Content="载入更多" Click="LoadMore_Click"/>
     </Grid>
 
     <phone:PhoneApplicationPage.ApplicationBar>

BoardPage.xaml.cs

@@ -82,40 +82,12 @@ private void Clear_Click(object sender, EventArgs e)
             }
         }
 
-        private void LoadMore_Click(object sender, RoutedEventArgs e)
+        private void TopicsList_NextPage(object sendor, NextPageEventArgs e)
         {
-            App.ViewModel.CurrentBoard.IsLoaded = false;
-            LoadMore.IsEnabled = false;
-            App.Service.Board(App.ViewModel.CurrentBoard.EnglishName, (currentPage + 1)* pageSize, pageSize, delegate(ObservableCollection<TopicViewModel> topics, bool success, string error)
-            {
-                // 判断后面是否还有内容
-                if (error == null && topics.Count < pageSize)
-                {
-                    LoadMore.Visibility = Visibility.Collapsed;
-                    LoadMore.IsEnabled = false;
-                }
-                else
-                {
-                    LoadMore.Visibility = Visibility.Visible;
-                    LoadMore.IsEnabled = true;
-                }
-
-                App.ViewModel.CurrentBoard.IsLoaded = true;
-                if (error == null)
-                {
-                    currentPage++;
-
-                    foreach (TopicViewModel topic in topics)
-                        App.ViewModel.CurrentBoard.Topics.Add(topic);
-                }
-                else
-                {
-                    MessageBox.Show("网络错误");
-                }
-            });
+            LoadTopics(true);
         }
 
-        private void Topic_Selected(object sender, SelectionChangedEventArgs e)
+        private void TopicsList_Selected(object sender, SelectionChangedEventArgs e)
         {
             if (e.AddedItems.Count == 1)
             {
@@ -131,29 +103,39 @@ private void Topic_Selected(object sender, SelectionChangedEventArgs e)
             }
         }
 
-        private void LoadTopics()
+        private void LoadTopics(bool append = false)
         {
-            LoadMore.IsEnabled = false;
-            App.ViewModel.CurrentBoard.IsLoaded = false;
+            if (App.ViewModel.CurrentBoard.IsLoading)
+                return;
+
+            App.ViewModel.CurrentBoard.IsLoading = true;
 
             // 重新加载
-            App.Service.Board(App.ViewModel.CurrentBoard.EnglishName, currentPage * pageSize, pageSize, delegate(ObservableCollection<TopicViewModel> topics, bool success, string error)
+            int page = append ? currentPage + 1 : currentPage;
+            App.Service.Board(App.ViewModel.CurrentBoard.EnglishName, page * pageSize, pageSize, delegate(ObservableCollection<TopicViewModel> topics, bool success, string error)
             {
+                App.ViewModel.CurrentBoard.IsLoading = false;
+
                 // 判断后面是否还有内容
-                if (error == null && topics.Count < pageSize)
-                {
-                    LoadMore.Visibility = Visibility.Collapsed;
-                    LoadMore.IsEnabled = false;
-                }
-                else
-                {
-                    LoadMore.Visibility = Visibility.Visible;
-                    LoadMore.IsEnabled = true;
-                }
+                TopicsList.IsFullyLoaded = error == null && topics.Count < pageSize;
 
-                App.ViewModel.CurrentBoard.IsLoaded = true;
                 if (error == null)
-                    App.ViewModel.CurrentBoard.Topics = topics;
+                    // 重置还是添加
+                    if (append)
+                    {
+                        ++currentPage;
+                        foreach (TopicViewModel topic in topics)
+                            App.ViewModel.CurrentBoard.Topics.Add(topic);
+
+                        // 叠加完毕时往后翻页
+
+                    }
+                    else
+                    {
+                        App.ViewModel.CurrentBoard.Topics = topics;
+                    }
+                else
+                    MessageBox.Show("网络错误");
             });
         }
     }

Controls/ExtendedListBox.cs

@@ -20,11 +20,34 @@ public class ExtendedListBox : ListBox
         protected bool _isBouncy = false;
         private bool alreadyHookedScrollEvents = false;
 
+        TextBlock LoadMoreText;
+
+        // 属性：是否完全载入
+        public bool IsFullyLoaded
+        {
+            get { return (bool)GetValue(IsFullyLoadedProperty); }
+            set { SetValue(IsFullyLoadedProperty, value); }
+        }
+
+        public static readonly DependencyProperty IsFullyLoadedProperty =
+            DependencyProperty.Register("IsFullyLoaded", typeof(bool), typeof(ExtendedListBox), new PropertyMetadata(false));
+
+        // 事件：拖到边界处
+        public delegate void OnNextPage(object sender, NextPageEventArgs e);
+        public event OnNextPage NextPage;
+
         public ExtendedListBox()
         {
             this.Loaded += new RoutedEventHandler(ListBox_Loaded);
         }
 
+        public override void OnApplyTemplate()
+        {
+            base.OnApplyTemplate();
+
+            LoadMoreText = (TextBlock)GetTemplateChild("LoadMoreText");
+        }
+
         private void ListBox_Loaded(object sender, RoutedEventArgs e)
         {
             ScrollBar sb = null;
@@ -54,45 +77,29 @@ private void ListBox_Loaded(object sender, RoutedEventArgs e)
 
         }
 
-        public delegate void OnCompression(object sender, CompressionEventArgs e);
-        public event OnCompression Compression;
-
         private void hgroup_CurrentStateChanging(object sender, VisualStateChangedEventArgs e)
         {
             if (e.NewState.Name == "CompressionLeft")
-            {
                 _isBouncy = true;
-                if (Compression != null)
-                    Compression(this, new CompressionEventArgs(CompressionType.Left));
-            }
-
-            if (e.NewState.Name == "CompressionRight")
-            {
+            else if (e.NewState.Name == "CompressionRight")
                 _isBouncy = true;
-                if (Compression != null)
-                    Compression(this, new CompressionEventArgs(CompressionType.Right));
-            }
-            if (e.NewState.Name == "NoHorizontalCompression")
-            {
+            else if (e.NewState.Name == "NoHorizontalCompression")
                 _isBouncy = false;
-            }
         }
 
         private void vgroup_CurrentStateChanging(object sender, VisualStateChangedEventArgs e)
         {
             if (e.NewState.Name == "CompressionTop")
             {
                 _isBouncy = true;
-                if (Compression != null)
-                    Compression(this, new CompressionEventArgs(CompressionType.Top));
             }
-            if (e.NewState.Name == "CompressionBottom")
+            else if (e.NewState.Name == "CompressionBottom")
             {
                 _isBouncy = true;
-                if (Compression != null)
-                    Compression(this, new CompressionEventArgs(CompressionType.Bottom));
+                if (NextPage != null && !IsFullyLoaded)
+                    NextPage(this, new NextPageEventArgs());
             }
-            if (e.NewState.Name == "NoVerticalCompression")
+            else if (e.NewState.Name == "NoVerticalCompression")
                 _isBouncy = false;
         }
 
@@ -138,15 +145,7 @@ private VisualStateGroup FindVisualState(FrameworkElement element, string name)
         }
     }
 
-    public class CompressionEventArgs : EventArgs
+    public class NextPageEventArgs : EventArgs
     {
-        public CompressionType Type { get; protected set; }
-
-        public CompressionEventArgs(CompressionType type)
-        {
-            Type = type;
-        }
     }
-
-    public enum CompressionType { Top, Bottom, Left, Right };
 }

Controls/UIPropertyMetadata.cs

@@ -0,0 +1 @@
+

ViewModels/CurrentBoardViewModel.cs

@@ -16,7 +16,7 @@ public class CurrentBoardViewModel : INotifyPropertyChanged
     {
         private string name;
         private string description;
-        private bool isLoaded;
+        private bool isLoading;
         private ObservableCollection<TopicViewModel> topics;
 
         // 全局变量，用于标记跳转到版面时是否需要刷新
@@ -70,18 +70,18 @@ public ObservableCollection<TopicViewModel> Topics
             }
         }
 
-        public bool IsLoaded
+        public bool IsLoading
         {
             get
             {
-                return isLoaded;
+                return isLoading;
             }
             set
             {
-                if (isLoaded != value)
+                if (isLoading != value)
                 {
-                    isLoaded = value;
-                    NotifyPropertyChanged("IsLoaded");
+                    isLoading = value;
+                    NotifyPropertyChanged("IsLoading");
                 }
             }
         }

sbbs-client-wp7.csproj

@@ -72,6 +72,7 @@
       <DependentUpon>BoardSettingsPage.xaml</DependentUpon>
     </Compile>
     <Compile Include="Controls\ExtendedListBox.cs" />
+    <Compile Include="Controls\UIPropertyMetadata.cs" />
     <Compile Include="DynamicOrientationChanges\AnimateOrientationChangesFrame.cs" />
     <Compile Include="DynamicOrientationChanges\FadeOrientationChangesFrame.cs" />
     <Compile Include="DynamicOrientationChanges\HybridOrientationChangesFrame.cs" />