[英]Temporarily Sort WP8 Listbox
我有一個基於本地數據庫示例( http://code.msdn.microsoft.com/wpapps/Local-Database-Sample-57b1614c )構建的WP C#應用程序。
主頁顯示xml數據庫中的項目列表,默認情況下按創建的順序顯示項目。 我希望能夠提供至少一種其他排序順序-顛倒或按“主題”排序。 不幸的是,WP不支持Listbox.Sort。
我已經嘗試過在這里找到各種答案,包括嘗試對xml文件本身進行排序,但是由於超出我的編碼水平,它們不會更改列表的順序(請參閱Templatestorage),但是我懷疑這是由於執行不當所致。
列表框的代碼是:
<ListBox x:Name="Templates" SelectionChanged="OnSelectionChanged" Background="Transparent" Style="{StaticResource ListBoxStyle1}">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel>
<TextBlock Grid.Row="2" Text="{Binding Subject}" Style="{StaticResource PhoneTextLargeStyle}" Margin="12,2" />
<TextBlock Grid.Row="2" Text="{Binding DT}" Style="{StaticResource PhoneTextSmallStyle}" Margin="12,5" />
<Rectangle Height="1" Margin="23,7,50,7" Fill="{StaticResource PhoneAccentBrush}" MinWidth="400" />
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
C#是:
public partial class MainPage
{
private readonly TemplateStorage storage = new TemplateStorage();
public MainPage()
{
InitializeComponent();
Loaded += OnLoaded;
}
private void OnLoaded(object sender, RoutedEventArgs e)
{
Templates.ItemsSource = storage.GetItems();
this.NavigationService.RemoveBackEntry();
}
private void PhoneApplicationPage_GotFocus(object sender, RoutedEventArgs e)
{
Templates.ItemsSource = storage.GetItems();
}
}
Templatestorage顯示了各種排序(注釋)嘗試:
public class TemplateStorage
{
private IList<NanoMemoTemplate> templates;
private const string Filename = "template-list.xml";
protected IList<NanoMemoTemplate> Templates
{
get
{
return templates ?? (templates = LoadTemplates().ToList());
}
set
{
templates = value;
}
}
protected IEnumerable<NanoMemoTemplate> LoadTemplates()
{
using(var applicationStorage = IsolatedStorageFile.GetUserStoreForApplication())
{
if(!applicationStorage.FileExists(Filename))
return Enumerable.Empty<NanoMemoTemplate>();
using(var speedListFile = applicationStorage.OpenFile(Filename, FileMode.Open, FileAccess.Read))
{
var document = XDocument.Load(speedListFile);
return from t in document.Root.Elements("template")
select new NanoMemoTemplate
{
Id = new Guid(t.Attribute("id").Value),
Subject = t.Attribute("subject").Value,
Body = t.Attribute("body").Value,
DT = t.Attribute("dateCreated").Value,
};
}
}
}
//public IEnumerable<NanoMemoTemplate> SortTemplates()
//{
// using (var applicationStorage = IsolatedStorageFile.GetUserStoreForApplication())
// {
// if (!applicationStorage.FileExists(Filename))
// return Enumerable.Empty<NanoMemoTemplate>();
// using (var speedListFile = applicationStorage.OpenFile(Filename, FileMode.Open, FileAccess.ReadWrite))
// {
// var documentSort = XDocument.Load(speedListFile);
// XDocument datatemp = new XDocument(documentSort);
// var subjectSort = from p in datatemp.Descendants("template")
// orderby (string)p.Attribute("subject")
// select p;
// //var subjectSort = datatemp.Elements("template").OrderBy(p => (string)p.Attribute("subject")).ToArray();
// string cleanDataDump = subjectSort.ToString();
// MessageBox.Show(cleanDataDump);
// documentSort.Descendants("template").Remove();
// documentSort.Element("template").Add(subjectSort);
// return Templates;
// }
// }
//}
//public IEnumerable<NanoMemoTemplate> SortItems()
//{
// //Sort XML order so order is saved
// using (var applicationStorage = IsolatedStorageFile.GetUserStoreForApplication())
// {
// if (!applicationStorage.FileExists(Filename))
// return Enumerable.Empty<NanoMemoTemplate>();
// using (var speedListFile = applicationStorage.OpenFile(Filename, FileMode.Open, FileAccess.ReadWrite))
// {
// var documentSort = XDocument.Load(speedListFile);
// IEnumerable<string> codes = from code in documentSort.Elements("template")
// let subs = (string)code.Element("subject")
// orderby subs
// select subs;
// //return Templates as per usual as sorting is done at DB level
// return from t in documentSort.Root.Elements("template")
// select new NanoMemoTemplate
// {
// Id = new Guid(t.Attribute("id").Value),
// Subject = t.Attribute("subject").Value,
// Body = t.Attribute("body").Value,
// DT = t.Attribute("dateCreated").Value,
// };
// }
// }
//}
public IEnumerable<NanoMemoTemplate> GetItems()
{
return Templates;
}
public void Save(NanoMemoTemplate template)
{
Templates.Add(template);
}
public void Delete(NanoMemoTemplate template)
{
Templates.Remove(template);
}
//public void Sort(NanoMemoTemplate template)
//{
// IList<NanoMemoTemplate> list = new List<NanoMemoTemplate>();
// IEnumerable<NanoMemoTemplate> sortedEnum = list.OrderBy(Templates => Templates.Subject);
// IList<NanoMemoTemplate> sortedList = sortedEnum.ToList();
//}
public void SaveChanges()
{
using(var applicationStorage = IsolatedStorageFile.GetUserStoreForApplication())
using(var speedListFile = applicationStorage.OpenFile(Filename, FileMode.Create, FileAccess.Write))
{
var document = new XDocument(new XDeclaration("1.0", "utf-8", "yes"),
new XElement("templates",
from t in Templates
select new XElement("template",
new XAttribute("id", t.Id),
new XAttribute("subject", t.Subject),
new XAttribute("body", t.Body),
new XAttribute("dateCreated", t.DT))));
document.Save(speedListFile);
}
}
}
無需設置Templates.ItemsSource = storage.GetItems();
在您的代碼中,可以將ObservableCollection(或其他可枚舉類型)保留為類級變量:
//StorageTemplates should be a class-level variable
ObservableCollection<NanoMemoTemplate> StorageTemplates;
//You can assign the value to StorageTemplates when the page loads
StorageTemplates = storage.GetItems();
然后,您將在XAML中將ItemsSource="{Binding StorageTemplates}"
數據綁定應用於您的ListBox。 ( 有關綁定的更多信息, 請參見此內容)
<ListBox x:Name="Templates" ItemsSource="{Binding StorageTemplates, UpdateSourceTrigger="PropertyChanged"}" SelectionChanged="OnSelectionChanged" Background="Transparent" Style="{StaticResource ListBoxStyle1}" >
<ListBox.ItemTemplate>
....
</ListBox.ItemTemplate>
</ListBox>
然后,您可以使用ObservableCollection
的內置Sort方法來設置項目的排序順序。 您可能需要實現屬性更改處理程序,可以查看本教程以獲取更多信息。
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