我希望能够按升序或降序对绑定到 LongListSelector 的数据进行排序。我无法将排序后的数据绑定到我的 LongListSelector。最初，我的解决方案没有尝试实现排序，而是有效的，但我相信在涉及排序时我遗漏了一些东西。我也尝试过如何使用 CollectionViewSource 对 LongListSelector 进行排序 https://stackoverflow.com/questions/18709361/how-to-sort-a-longlistselector-using-collectionviewsource?noredirect=1#comment27573580_18709361没有运气。对 LongListSelector 进行排序的最佳方法是什么？
主页.xaml
<phone:LongListSelector x:Name="Recent" Margin="0,0,0,72"
LayoutMode="Grid" GridCellSize="108,108"
SelectionChanged="recent_SelectionChanged">
MainPage.xaml.cs（旧）
protected override void OnNavigatedTo(NavigationEventArgs e)
{
Recent.ItemsSource = App.PictureList.Pictures; //works!
if (Settings.AscendingSort.Value)
{
//Recent.ItemsSource = App.PictureList.Pictures.OrderBy(x => x.DateTaken); //Error stating Cannot implicityly convert type 'SYstem.Linq.IOrderedEnumerable to System.Collections.IList
Recent.ItemsSource = App.PictureList.Pictures.OrderBy(x => x.DateTaken) as System.Collections.IList; //No error but nothing is displayed
}
else
{
//Recent.ItemsSource = App.PictureList.Pictures.OrderByDescending(x => x.DateTaken);
Recent.ItemsSource = App.PictureList.Pictures.OrderByDescending(x => x.DateTaken) as System.Collections.IList;
}
}
**EDIT
MainPage.xaml.cs（新）
protected override void OnNavigatedTo(NavigationEventArgs e)
{
//Recent.ItemsSource = App.PictureList.Pictures; //Works with deleting, not sorted.
if (Settings.AscendingSort.Value)
{
//Recent.ItemsSource = App.PictureList.Pictures.OrderBy(x => x.DateTaken).ToList();
//Recent.ItemsSource = new ObservableCollection<Models.Picture>(App.PictureList.Pictures.OrderBy(x => x.DateTaken));
App.PictureList.Pictures = new ObservableCollection<Models.Picture>(App.PictureList.Pictures.OrderBy(x => x.DateTaken)); //Error
Recent.ItemsSource = App.PictureList.Pictures;
}
else
{
//Recent.ItemsSource = App.PictureList.Pictures.OrderByDescending(x => x.DateTaken).ToList();
//Recent.ItemsSource = new ObservableCollection<Models.Picture>(App.PictureList.Pictures.OrderByDescending(x => x.DateTaken));
App.PictureList.Pictures = new ObservableCollection<Models.Picture>(App.PictureList.Pictures.OrderByDescending(x => x.DateTaken)); //Error
Recent.ItemsSource = App.PictureList.Pictures;
}
}
应用程序.xaml.cs
public static PictureRepository PictureList
{
get
{
return PictureRepository.Instance;
}
}
图片库.cs
#region Constants
public const string IsolatedStoragePath = "Pictures";
#endregion
#region Fields
//private readonly ObservableCollection<Picture> _pictures = new ObservableCollection<Picture>();
private ObservableCollection<Picture> _pictures = new ObservableCollection<Picture>();
#endregion
#region Properties
public ObservableCollection<Picture> Pictures
{
//get { return _pictures; }
get { return _pictures; }
set { new ObservableCollection<Picture>(_pictures); }
}
#endregion
#region Singleton Pattern
private PictureRepository()
{
LoadAllPicturesFromIsolatedStorage();
}
public static readonly PictureRepository Instance = new PictureRepository();
#endregion
/// <summary>
/// Saves to local storage
/// This method gets two parameters: the captured picture instance and the name of the pictures folder in the isolated storage
/// </summary>
/// <param name="capturedPicture"></param>
/// <param name="directory"></param>
public void SaveToLocalStorage(CapturedPicture capturedPicture, string directory)
{
//call IsolatedStorageFile.GetUserStoreForApplication to get an isolated storage file
var isoFile = IsolatedStorageFile.GetUserStoreForApplication();
//Call the IsolatedStorageFile.EnsureDirectory extension method located in the Common IsolatedStorageFileExtensions class to confirm that the pictures folder exists.
isoFile.EnsureDirectory(directory);
//Combine the pictures folder and captured picture file name and use this path to create a new file
string filePath = Path.Combine(directory, capturedPicture.FileName);
using (var fileStream = isoFile.CreateFile(filePath))
{
using (var writer = new BinaryWriter(fileStream))
{
capturedPicture.Serialize(writer);
}
}
}
/// <summary>
/// To load all saved pictures and add them to the pictures list page
/// </summary>
public CapturedPicture LoadFromLocalStorage(string fileName, string directory)
{
//To open the file, add a call to the IsolatedStorageFile.GetUserStoreForApplication
var isoFile = IsolatedStorageFile.GetUserStoreForApplication();
//Combine the directory and file name
string filePath = Path.Combine(directory, fileName);
//use the path to open the picture file from the isolated storage by using the IsolatedStorageFile.OpenFile method
using (var fileStream = isoFile.OpenFile(filePath, FileMode.Open, FileAccess.Read))
{
//create a BinaryReader instance for deserializing the CapturedPicture instance
using (var reader = new BinaryReader(fileStream))
{
var capturedPicture = new CapturedPicture();
//create a new instance of the type CapturedPicture called CapturedPicture.Deserialize to deserialize the captured picture and return it
capturedPicture.Deserialize(reader);
return capturedPicture;
}
}
}
/// <summary>
/// To load all the pictures at start time
/// </summary>
private void LoadAllPicturesFromIsolatedStorage()
{
//add call to the IsolatedStorageFile.GetUserStoreForApplication to open an isolated storage file
var isoFile = IsolatedStorageFile.GetUserStoreForApplication();
//Call the IsolatedStorageFile.EnsureDirectory extension method located in the Common IsolatedStorageFileExtensions class to confirm that the pictures folder exists
isoFile.EnsureDirectory(IsolatedStoragePath);
//Call the IsolatedStorageFile.GetFileNames using the pictures directory and *.jpg as a filter to get all saved pictures
var pictureFiles = isoFile.GetFileNames(Path.Combine(IsolatedStoragePath, "*.jpg"));
//var pictureFiles = isoFile.GetFileNames(Path.Combine(IsolatedStoragePath, ""));
//Iterate through all the picture files in the list and load each using the LoadFromLocalStorage you created earlier
foreach (var pictureFile in pictureFiles)
{
var picture = LoadFromLocalStorage(pictureFile, IsolatedStoragePath);
_pictures.Add(picture);
}
}
