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我正在尝试在 Windows Phone 7.1 项目中实现“无限滚动”。

大多数其他帖子都指向此MSDN 博客链接。

不过，我正在努力实现这一点，因为它并没有真正说明它是如何工作的或将代码放在哪里。另外，当我粘贴代码时，它似乎缺少空格，所以我浏览了代码并添加了缺少的空格并尽我所知对其进行了编辑。

我已经将 XAML 代码添加到了<Application.Resources>这App.xaml是正确的，这是我的App.xaml文件的内容：

<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>

这是我的MainPage.xaml.cs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; 
       }
    }
}

有了这两段代码，当我尝试将我的应用程序运行到模拟器时，我只会收到很多错误：

在此处输入图像描述

4

1 回答 1

1

您似乎缺少所需的主要 XAML，即。上的MainListBox元素MainPage.xaml。您添加了从文章中引用它的代码，但实际上并没有ListBox在您尝试使用它的页面上获得。

我建议您从链接的 MSDN 博客文章中下载 ZIP 文件并查看完整示例以了解您需要从那里获得哪些代码。

另请注意，此解决方案是较旧的方法，LongListSelector现在建议使用新方法。如需更多参考，请参阅Microsoft 在 LongListSelector 上的这篇博文，以及Windows Phone Toolkit以获取LongListSelector您自己的项目（请注意，它本机包含在 Windows Phone 8 中）。

于 2013-01-09T12:15:20.540 回答