WindowsPhone7.1プロジェクト内に「無限スクロール」を実装しようとしています。
他のほとんどの投稿は、このMSDNブログリンクを指しています。
しかし、これを実装するのに苦労しています。なぜなら、それがどのように機能するか、またはコードをどこに置くかについては、実際にはあまりわかりません。また、コードを貼り付けると、スペースが不足しているように見えるので、コードを調べて不足しているスペースを追加し、私の知る限り編集しました。
XAMLコードをに追加しました。<Application.Resources>これApp.xamlは正しいApp.xamlです。ファイルの内容は次のとおりです。
<Application
x:Class="ScrollWindowBottom.App"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"
xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone">
<!--Application Resources-->
<Application.Resources>
<Style TargetType="ScrollViewer">
<Setter Property="VerticalScrollBarVisibility" Value="Auto"/>
<Setter Property="HorizontalScrollBarVisibility" Value="Auto"/>
<Setter Property="Background" Value="Transparent"/>
<Setter Property="Padding" Value="0"/>
<Setter Property="BorderThickness" Value="0"/>
<Setter Property="BorderBrush" Value="Transparent"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="ScrollViewer">
<Border BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}"
Background="{TemplateBinding Background}">
<VisualStateManager.VisualStateGroups>
<VisualStateGroup x:Name="ScrollStates">
<VisualStateGroup.Transitions>
<VisualTransition GeneratedDuration="00:00:00.5"/>
</VisualStateGroup.Transitions>
<VisualState x:Name="Scrolling">
<Storyboard>
<DoubleAnimation Storyboard.TargetName="VerticalScrollBar"
Storyboard.TargetProperty="Opacity" To="1" Duration="0"/>
<DoubleAnimation Storyboard.TargetName="HorizontalScrollBar"
Storyboard.TargetProperty="Opacity" To="1" Duration="0"/>
</Storyboard>
</VisualState>
<VisualState x:Name="NotScrolling">
</VisualState>
</VisualStateGroup>
<VisualStateGroup x:Name="VerticalCompression">
<VisualState x:Name="NoVerticalCompression"/>
<VisualState x:Name="CompressionTop"/>
<VisualState x:Name="CompressionBottom"/>
</VisualStateGroup>
<VisualStateGroup x:Name="HorizontalCompression">
<VisualState x:Name="NoHorizontalCompression"/>
<VisualState x:Name="CompressionLeft"/>
<VisualState x:Name="CompressionRight"/>
</VisualStateGroup>
</VisualStateManager.VisualStateGroups>
<Grid Margin="{TemplateBinding Padding}">
<ScrollContentPresenter x:Name="ScrollContentPresenter" Content="{TemplateBinding Content}"
ContentTemplate="{TemplateBinding ContentTemplate}"/>
<ScrollBar x:Name="VerticalScrollBar" IsHitTestVisible="False" Height="Auto" Width="5"
HorizontalAlignment="Right" VerticalAlignment="Stretch" Visibility="{TemplateBinding ComputedVerticalScrollBarVisibility}"
IsTabStop="False" Maximum="{TemplateBinding ScrollableHeight}" Minimum="0" Value="{TemplateBinding VerticalOffset}"
Orientation="Vertical" ViewportSize="{TemplateBinding ViewportHeight}" />
<ScrollBar x:Name="HorizontalScrollBar" IsHitTestVisible="False" Width="Auto" Height="5"
HorizontalAlignment="Stretch" VerticalAlignment="Bottom" Visibility="{TemplateBinding ComputedHorizontalScrollBarVisibility}"
IsTabStop="False" Maximum="{TemplateBinding ScrollableWidth}" Minimum="0" Value="{TemplateBinding HorizontalOffset}"
Orientation="Horizontal" ViewportSize="{TemplateBinding ViewportWidth}" />
</Grid>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</Application.Resources>
<Application.ApplicationLifetimeObjects>
<!--Required object that handles lifetime events for the application-->
<shell:PhoneApplicationService
Launching="Application_Launching" Closing="Application_Closing"
Activated="Application_Activated" Deactivated="Application_Deactivated"/>
</Application.ApplicationLifetimeObjects>
</Application>
これが私のMainPage.xaml.csファイルです：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using Microsoft.Phone.Controls;
namespace ScrollWindowBottom
{
public partial class MainPage : PhoneApplicationPage
{
// Constructor
public MainPage()
{
InitializeComponent();
}
private void MainPage_Loaded(object sender, RoutedEventArgs e)
{
if(!App.ViewModel.IsDataLoaded)
{
App.ViewModel.LoadData();
}
if(alreadyHookedScrollEvents)
return;
alreadyHookedScrollEvents = true;
MainListBox.AddHandler(ListBox.ManipulationCompletedEvent, (EventHandler<ManipulationCompletedEventArgs>)LB_ManipulationCompleted, true);
sb = (ScrollBar)FindElementRecursive(MainListBox, typeof(ScrollBar));
sv = (ScrollViewer)FindElementRecursive(MainListBox, typeof(ScrollViewer));
if(sv != null)
{
// Visual States are always on the first child of the control template
FrameworkElement element = VisualTreeHelper.GetChild(sv, 0) as FrameworkElement;
if(element != null)
{
VisualStateGroup group = FindVisualState(element, "ScrollStates");
if(group != null)
{
group.CurrentStateChanging += newEventHandler<VisualStateChangedEventArgs>(group_CurrentStateChanging);
}
VisualStateGroup vgroup = FindVisualState(element, "VerticalCompression");
VisualStateGroup hgroup = FindVisualState(element, "HorizontalCompression");
if(vgroup != null)
{
vgroup.CurrentStateChanging += newEventHandler<VisualStateChangedEventArgs>(vgroup_CurrentStateChanging);
}
if(hgroup != null)
{
hgroup.CurrentStateChanging += newEventHandler<VisualStateChangedEventArgs>(hgroup_CurrentStateChanging);
}
}
}
}
private UIElement FindElementRecursive(FrameworkElement parent, Type targetType)
{
int childCount = VisualTreeHelper.GetChildrenCount(parent);
UIElement returnElement = null;
if (childCount > 0)
{
for (int i = 0; i < childCount; i++)
{
Object element = VisualTreeHelper.GetChild(parent, i);
if (element.GetType() == targetType)
{
return element as UIElement;
}
else
{
returnElement = FindElementRecursive(VisualTreeHelper.GetChild(parent, i) as FrameworkElement, targetType);
}
}
}
return returnElement;
}
private VisualStateGroup FindVisualState(FrameworkElement element, string name)
{
if (element == null)
return null;
IList groups = VisualStateManager.GetVisualStateGroups(element);
foreach (VisualStateGroup group in groups)
if (group.Name == name)
return group;
return null;
}
}
}
これらの2つのコードを配置した状態で、アプリケーションをエミュレーターで実行しようとすると、エラーが大量に発生します。
