Question

我对Windows Phone的编程很新，我在ListBox中编辑数据时遇到了麻烦我正在将XML文件中的数据加载到列表中，并将它们显示在ListBox中我的XML中的每个条目都附加了一个类型。我想通过选中/取消选中某些CheckBox来删除/添加某些类型的条目。

我发现了这样的事情：
How to remove all ListBox items?

但它并不完全符合我的需要，因为我只想删除部分ListBox项目，然后只需再次勾选复选框就可以取回它。
此外，我不想手动添加每个条目，因为我已经将listbox与包含我的XML条目的列表绑定在一起。

我像这样上传我的XML：

Activity.cs：

namespace ReadXMLfromFile
{
   public class Activity
   {
      public string Type { get; private set; }
      public string Description { get; private set; }

      public Activity(string type, string description)
      {
           Type = type;
           Description = description;
      }

      public static List<Activity> LoadActivities(XDocument doc)
      {
        return doc .Root
                   .Elements("Activity")
                   .Select(el => new Activity((string)el.Attribute("Type"),
                                            el.Value))
                   .ToList();
      }

      public static List<Activity> LoadActivities()
      {
        using (var store = IsolatedStorageFile.GetUserStoreForApplication())
        {
            if (store.FileExists("Activities.xml"))
            {
                 using (var stream = store.OpenFile("Activities.xml",
                                                    FileMode.Open))
                 {
                     return LoadActivities(XDocument.Load(stream));
                 }
            }
        }
        // No user file... load the default activities
        return LoadActivities(XDocument.Load("Assets/Activities.xml"));

      }
   }
}

这是我的页面代码：

namespace ActivityManager
{
    public partial class PivotPage1 : PhoneApplicationPage
    {
        private List<Activity> activities;

        public void ActivityDisplay()
        {
            activities = Activity.LoadActivities();
            listBox1.ItemsSource = activities;
        }

        public PivotPage1()
        {
            InitializeComponent();
            ActivityDisplay();
        }

        private void CookingCheck_Checked(object sender, RoutedEventArgs e)
        {
        }

        private void ArtCheck_Checked(object sender, RoutedEventArgs e)
        {
        }

        private void LanguageCheck_Checked(object sender, RoutedEventArgs e)
        {
        }

        private void ScienceCheck_Checked(object sender, RoutedEventArgs e)
        {
        }

        private void SportCheck_Checked(object sender, RoutedEventArgs e)
        {
        }

ListBox的xaml：

<ListBox Height="347" HorizontalAlignment="Left" Margin="27,243,0,0" 
         Name="listBox1" VerticalAlignment="Top" Width="410" 
         SelectionChanged="listBox1_SelectionChanged" AllowDrop="False" 
         ItemsSource="{Binding activities}">
     <ListBox.ItemTemplate>
         <DataTemplate>
              <StackPanel Margin="10">
                   <TextBlock Text="{Binding Activity}"/>
              </StackPanel>
         </DataTemplate>
     </ListBox.ItemTemplate>
 </ListBox>

此处还有我的XML文件

<?xml version="1.0" encoding="utf-8" ?>
<Activities>
    <Activity Type="Cooking">
      Cook some Mexican food
    </Activity>
    <Activity Type="Art">
      Draw a picture
    </Activity>
    <Activity Type="Language">
      Learn 5 words in Polish you didn't know yet
    </Activity>
    <Activity Type="Science">
      Write a simple program in C
    </Activity>
    <Activity Type="Sport">
      Go to the gym
    </Activity>
  </Activities>

你能帮帮我吗？我很困难，可能会遗漏一些明显的东西。提前谢谢。

Answer 1

你应该这样做：
创建过滤器列表选中/取消选中复选框时更新过滤器列表，并在每次过滤器更改时更新列表

private List<Activity> activities;

public void ActivityDisplay()
{
    activities = Activity.LoadActivities();
    FilterActivities();
}

public ObservableCollection<string> ActivityFilter = new ObservableCollection<string>();

private void FilterActivities()
{
    listbox1.ItemsSource = null; //sometimes it makes the difference;
    listBox1.ItemsSource = activities.Where(activity => ActivityFilter.Any(filter => filter == activity.Type) || ActivityFilter.Count == 0);

}

public PivotPage1()
{
    InitializeComponent();
    ActivityFilter.CollectionChanged += ActivityFilter_CollectionChanged;
    ActivityDisplay();
}

void ActivityFilter_CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
{
    FilterActivities();
}

private void CookingCheck_Checked(object sender, RoutedEventArgs e)
{
    ActivityFilter.Add("Cooking");
}

private void CookingCheck_Unchecked(object sender, RoutedEventArgs e)
{
    ActivityFilter.Remove("Cooking");
}

//Repeat the procedure for each checkbox

我在ItemTemplate中发现了一个使用此问题的问题

 <ListBox.ItemTemplate>
     <DataTemplate>
          <StackPanel Margin="10">
               <TextBlock Text="{Binding Description}"/>
          </StackPanel>
     </DataTemplate>
 </ListBox.ItemTemplate>

使用CheckBoxes过滤ListBox.ItemsSource

1 个答案: