自动筛选/排序ListBox项(Windows Phone) [英] Automatically filter/order ListBox items (Windows Phone)
问题描述
我想确保添加到列表框中的项目是根据每个项目的序列号升序排列的(例如1个项目，2个项目，4个项目，3个项目应根据其编号自动进行排序) 1.2.3 ....... 10).
I want to ensure, that the items added in my list box are ordered in ascending order according to the serial number of each item (e.g 1 item, 2 item, 4 item, 3 item should be automatically order according to its number 1.2.3.......10).
这是C#来源:
namespace XeroQuiz
{
public partial class MainPage : PhoneApplicationPage
{
IsolatedStorageFile Settings1 = IsolatedStorageFile.GetUserStoreForApplication();
MyDataList listobj = new MyDataList();
public MainPage()
{
InitializeComponent();
this.Loaded += MainPage_Loaded;
this.FavoriteListBox.Visibility = Visibility.Collapsed;
if (Settings1.FileExists("MyStoreItems"))
{
using (IsolatedStorageFileStream fileStream = Settings1.OpenFile("MyStoreItems", FileMode.Open))
{
DataContractSerializer serializer = new DataContractSerializer(typeof(MyDataList));
listobj = (MyDataList)serializer.ReadObject(fileStream);
}
}
FavoriteListBox.ItemsSource = listobj;//binding isolated storage list data
DispatcherTimer timer = new DispatcherTimer { Interval = TimeSpan.FromSeconds(0.5) };
timer.Tick += delegate (object sender, EventArgs e)
{
// var sortedList = listobj.OrderBy(item => item.AnswerName).ToList(); code is correct but no item is sorted in list.
this.FavoriteListBox.ItemsSource = listobj;
this.FavoriteListBox.UpdateLayout();
};
timer.Start();
}
/**************************************************************************/
private void MainPage_Loaded(object sender, RoutedEventArgs e)
{
if (Settings1.FileExists("MyStoreItems"))//loaded previous items into list
{
using (IsolatedStorageFileStream fileStream = Settings1.OpenFile("MyStoreItems", FileMode.Open))
{
DataContractSerializer serializer = new DataContractSerializer(typeof(MyDataList));
listobj = (MyDataList)serializer.ReadObject(fileStream);
}
}
}
private void FavoriteButton_Click(object sender, RoutedEventArgs e)
{
if (listobj.Any(l => l.AnswerName == AnswerTextBlock.Text))
return;
//var sortedList = listobj.OrderBy(item => item.ToString()).ToList();
listobj.Add(new MyData { AnswerName = AnswerTextBlock.Text });
using (IsolatedStorageFileStream fileStream = Settings1.OpenFile("MyStoreItems", FileMode.Create))
{
DataContractSerializer serializer = new DataContractSerializer(typeof(MyDataList));
serializer.WriteObject(fileStream, listobj);
}
}
private void FavoriteRemoveButton_Click(object sender, RoutedEventArgs e)
{
lsitobj.Remove(listobj.FirstOrDefault(l => l.AnswerName == AnswerTextBlock.Text));
using (IsolatedStorageFileStream fileStream = Settings1.OpenFile("MyStoreItems", FileMode.Create))
{
DataContractSerializer serializer = new DataContractSerializer(typeof(MyDataList));
serializer.WriteObject(fileStream, listobj);
}
}
}
private void FavoriteListButton_Click(object sender, RoutedEventArgs e)
{
if (FavoriteListBox.Visibility.Equals(Visibility.Collapsed))
{
FavoriteListBox.Visibility = Visibility.Visible;
}
else if (FavoriteListBox.Visibility.Equals(Visibility.Visible))
{
FavoriteListBox.Visibility = Visibility.Collapsed;
}
}
public class MyData
{
public string AnswerName { get; set; }
}
public class MyDataList : ObservableCollection<MyData>//for storing mydata class items with type of list
{
}
private void FavoriteListBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
MyData selecteddata = (sender as ListBox).SelectedItem as MyData;
if (selecteddata != null)
{
FavoritedData.Text = selecteddata.FrequencyName.ToString();
using (IsolatedStorageFileStream fileStream = Settings1.OpenFile("MySelectedStoreItem", FileMode.Create))
{
DataContractSerializer serializer = new DataContractSerializer(typeof(MyData));
serializer.WriteObject(fileStream, selecteddata);
}
}
}
}
这是XAML代码:
<StackPanel Grid.Column="1" Grid.Row="0" HorizontalAlignment="Center" VerticalAlignment="Top">
<ListBox x:Name="FavoriteListBox" Visibility="Collapsed"
SelectionChanged="FavoriteListBox_SelectionChanged"
HorizontalAlignment="Stretch"
VerticalAlignment="Top" Opacity="1"
Background="{StaticResource PhoneBackgroundBrush}" Foreground="{StaticResource PhoneForegroundBrush}"
Height="300" Width="250">
<ListBox.ItemTemplate>
<DataTemplate>
<TextBlock Visibility="Visible" x:Name="FavoriteListBoxTextBlock"
FontSize="35" Foreground="Black" Text="{Binding AnswerName}"/>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</StackPanel>
<StackPanel Grid.Row="0" Grid.Column= "0" HorizontalAlignment= "Left" VerticalAlignment= "Top" >
< Button x:Name= "FavoriteButton" FontFamily= "Segoe MDL2 Assets"
Content= "" BorderBrush= "Transparent" FontSize= "28"
Foreground= "{StaticResource PhoneForegroundBrush}"
Style= "{StaticResource ButtonStyle1}" Click= "FavoriteButton_Click" />
</ StackPanel >
<StackPanel Grid.Row="0" Grid.Column= "2" HorizontalAlignment= "Left" VerticalAlignment= "Top" >
< Button x:Name= "FavoriteListButton" FontFamily= "Segoe MDL2 Assets"
Content= "" BorderBrush= "Transparent" FontSize= "28"
Foreground= "{StaticResource PhoneForegroundBrush}"
Style= "{StaticResource ButtonStyle1}" Click= "FavoriteListButton_Click" />
</StackPanel>
推荐答案
在MainPage构造函数中，您具有排序代码，但未将内容设置为列表框，因此未显示该列表框
In the MainPage constructor you have the sort code, but you don't set the content to the list box, which is why it didn't display in sorted order.
var sortedList = listobj.OrderBy(item => item.AnswerName).ToList();
this.FavoriteListBox.ItemsSource = sortedList; //you were using listobj, which isn't sorted
对于FavoriteButton_Click处理程序，您遇到类似的情况-您正在将排序的结果排序并将其保存到新列表中，这不会影响原始的listobj实例. OrderBy是LINQ扩展，不会影响原始实例，因此您只能手动清除这些项目并将其重新添加到原始实例.
For the FavoriteButton_Click handler, you have a similar situation - you were sorting and saving the sorted results into a new list, which did not affect the original listobj instance. OrderBy is a LINQ extension which does not affect the original instance, so you can only clear and re-add the items to the original instance manually.
private void FavoriteButton_Click(object sender, RoutedEventArgs e)
{
if (listobj.Any(l => l.AnswerName == AnswerTextBlock.Text))
return;
//add
listobj.Add(new MyData { AnswerName = AnswerTextBlock.Text });
//sort (does not modify the original listobj instance!)
var sortedList = listobj.OrderBy(item => item.ToString()).ToList();
//clear and re-add all items in the sorted order
listobj.Clear();
foreach( var item in sortedList )
{
listobj.Add( item );
}
using (IsolatedStorageFileStream fileStream = Settings1.OpenFile("MyStoreItems", FileMode.Create))
{
DataContractSerializer serializer = new DataContractSerializer(typeof(MyDataList));
serializer.WriteObject(fileStream, listobj);
}
}
还有一个建议-您不必使用MyDataList类型，您可以在任何地方直接使用ObservableCollection<MyData>.
Also as a suggestion - you don't have to use MyDataList type, you can directly use ObservableCollection<MyData> everywhere.
如您所见，此代码很难维护和保持功能.因此，建议您阅读一些有关设计模式或Windows应用程序开发的书，尤其是要了解 MVVM 模式，数据绑定和 INotifyPropertyChanged >.这些对于构建可维护和稳定的Windows应用程序非常重要.
As you can see this code is getting quite hard to maintain and keep functional. For that reason I suggest you to read some book on design patterns or Windows app development, especially to learn about MVVM pattern, data-binding and INotifyPropertyChanged. These are quite essential in building maintainable and stable Windows applications.
另外，我认为学习一些更好的C#代码约定将很有帮助-使用更一致的变量命名(避免使用Settings1，listobj之类的东西)，注释和代码结构来提高可读性.这需要时间，但最终结果值得付出努力:-).
Also I think it would be helpful to learn some better C# code conventions - for better readability with more consistent variable naming (avoiding things like Settings1, listobj), commenting and code structure. It takes time but the end result is well worth the effort :-) .
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