我想将 OservableCollection 中的特定图像绑定到我的视图。我正在尝试为此使用 LINQ，并且我相信我得到了正确的图像，尽管视图没有显示任何内容。到目前为止，我所拥有的如下：
ImagePage.xaml
<Image x:Name="photo" Grid.Row="0" Source="{Binding}" Margin="12"
HorizontalAlignment="Center" VerticalAlignment="Center"
toolkit:TiltEffect.IsTiltEnabled="True"/>
应用程序.xaml.cs
public static PictureRepository PictureList
{
get
{
//Gets the ObservableCollection of images from IsolatedStorage
return PictureRepository.Instance;
}
}
ImagePage.xaml.cs
private void GetImage(string fileDate)
{
//if (fileName != null)
if(fileDate != null)
{
var p = App.PictureList.Pictures.Where(x => x.DateTaken.ToString() == fileDate).FirstOrDefault();
if (p != null)
{
photo.DataContext = p;
}
}
图片库.cs
#region Constants
public const string IsolatedStoragePath = "Pictures";
#endregion
#region Fields
private readonly ObservableCollection<Picture> _pictures = new ObservableCollection<Picture>();
#endregion
#region Properties
public ObservableCollection<Picture> Pictures
{
get { return _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"));
//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);
}
}
图片.cs
[DataMember]
public string Address
{
get { return GetValue(() => Address); }
set { SetValue(() => Address, value); }
}
[DataMember]
public string Note
{
get { return GetValue(() => Note); }
set { SetValue(() => Note, value); }
}
[DataMember]
public DateTime DateTaken
{
get { return GetValue(() => DateTaken); }
set { SetValue(() => DateTaken, value); }
}
[IgnoreDataMember]
public BitmapSource Source
{
get
{
return CreateBitmapSource();
}
}
protected abstract BitmapSource CreateBitmapSource();
//In the Serialize method, store the Position, Address, Note, and DateTaken properties
public virtual void Serialize(BinaryWriter writer)
{
writer.Write(DateTaken.ToString()); //writer.WriteString(DateTaken);
}
//In the Deserialize method, read the data in the same order you’ve written it
public virtual void Deserialize(BinaryReader reader)
{
DateTaken = DateTime.Parse(reader.ReadString());
}
调试时，我可以看到它p包含图像的正确日期并且它不为空，但我在视图中看不到任何内容？