无限滚动 - 的Windows Phone 7/8Windows、Phone
我试图实施无限滚动内的Windows Phone 7.1的项目。
I'm trying to implement the "infinite scrolling" within a Windows Phone 7.1 project.
大多数其他职位指向这个 MSDN博客链接。
Most other posts point to this MSDN Blog link.
我在努力实现这一点，因为它并没有真正慷慨解囊，以它是如何工作或者把code。此外，当我贴code，它似乎有空间的缺失，所以我一直通过code和补充丢失的空间，并将其编辑尽我的知识。
I'm struggling to implement this though, because it doesn't really give much away as to how it works or where to put the code. Also, when I paste the code, it appears to have spaces missing, so I have been through the code and added missing spaces and editing it to the best of my knowledge.
我已经加入了XAML code到＆LT; Application.Resources＆GT; 的的App.xaml 这是正确的，这是我的的App.xaml 文件的内容：
I have added the XAML code to the <Application.Resources> of the App.xaml is this correct, here is the contents of my App.xaml file:
<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>
下面是我的 MainPage.xaml.cs中文件：
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;
}
}
}
通过这两条code的地方，当我尝试运行我的应用程序到模拟器我只是得到错误的负载：
With these two pieces of code in place, when I try to run my application to the Emulator I just get a load of errors:
推荐答案
看来你缺少所需的主要XAML，即。在 MainPage.xaml中的 MainListBox 元素。您已经添加了code，从这篇文章引用它，但实际上没有得到一个列表框你想使用它的页面上。
It appears that you're missing the main XAML required, ie. the MainListBox element on MainPage.xaml. You have added code that references it from the article, but not actually got a ListBox on the page you're trying to use it on.
我会建议下载从你的链接MSDN博客文章ZIP文件，并采取一看完整的例子，看看有什么code，你需要从那里。
I would recommend downloading the ZIP file from your linked MSDN Blog Article and taking a look at the full example to see what code you'll need from there.
另请注意，这个解决方案是这样做的旧方法，并采用了新的途径 LongListSelector 现在推荐。欲了解更多信息参见从微软LongListSelector 这个博客帖子，也是的Windows Phone工具包弄个 LongListSelector 你自己的项目（注意，包括原生的Windows Phone 8）。
Note also that this solution is the older method of doing it, and a new way using LongListSelector is now recommended. For more reference see this blog post from Microsoft on LongListSelector and also the Windows Phone Toolkit to get hold of LongListSelector for your own projects (note that it is included natively in Windows Phone 8).
