ObservableCollection をシリアライズしようとしています。しかし、次のエラーが表示されます: Let me know how can I fix this?
エラー：
{System.InvalidOperationException: タイプ 'System.Collections.ObjectModel.ObservableCollection 1.MoveNext() を f:\TFS\New TFS\PDFReader\Posh.PdfReader.Win8\eText\Common\ApplicationSettings.cs:line に反映するエラーが発生しました16 --- 例外がスローされた前の場所からのスタック トレースの終了 --- System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) で System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) で System.Runtime .CompilerServices.TaskAwaiter.GetResult() at eText.ViewModel.MainViewModel.d__a.MoveNext() in f:\TFS\New TFS\PDFReader\Posh.PdfReader.Win8\eText\ViewModel\MainViewModel.cs:line 268}
1[eText.DataModel.BooksDownloadedData]'. ---> System.InvalidOperationException: There was an error reflecting type 'eText.DataModel.BooksDownloadedData'. ---> System.InvalidOperationException: Cannot serialize member 'eText.DataModel.BooksDownloadedData.DownloadedBookFileDetails' of type 'Windows.Storage.StorageFile', see inner exception for more details. ---> System.InvalidOperationException: Windows.Storage.StorageFile cannot be serialized because it does not have a parameterless constructor. --- End of inner exception stack trace --- at System.Xml.Serialization.StructModel.CheckSupportedMember(TypeDesc typeDesc, MemberInfo member, Type type) at System.Xml.Serialization.StructModel.GetPropertyModel(PropertyInfo propertyInfo) at System.Xml.Serialization.StructModel.GetFieldModel(MemberInfo memberInfo) at System.Xml.Serialization.XmlReflectionImporter.InitializeStructMembers(StructMapping mapping, StructModel model, Boolean openModel, String typeName, RecursionLimiter limiter) at System.Xml.Serialization.XmlReflectionImporter.ImportStructLikeMapping(StructModel model, String ns, Boolean openModel, XmlAttributes a, RecursionLimiter limiter) at System.Xml.Serialization.XmlReflectionImporter.ImportTypeMapping(TypeModel model, String ns, ImportContext context, String dataType, XmlAttributes a, Boolean repeats, Boolean openModel, RecursionLimiter limiter) --- End of inner exception stack trace --- at System.Xml.Serialization.XmlReflectionImporter.ImportTypeMapping(TypeModel model, String ns, ImportContext context, String dataType, XmlAttributes a, Boolean repeats, Boolean openModel, RecursionLimiter limiter) at System.Xml.Serialization.XmlReflectionImporter.CreateArrayElementsFromAttributes(ArrayMapping arrayMapping, XmlArrayItemAttributes attributes, Type arrayElementType, String arrayElementNs, RecursionLimiter limiter)
at System.Xml.Serialization.XmlReflectionImporter.ImportArrayLikeMapping(ArrayModel model, String ns, RecursionLimiter limiter) at System.Xml.Serialization.XmlReflectionImporter.ImportTypeMapping(TypeModel model, String ns, ImportContext context, String dataType, XmlAttributes a, Boolean repeats, Boolean openModel, RecursionLimiter limiter) --- End of inner exception stack trace --- at System.Xml.Serialization.XmlReflectionImporter.ImportTypeMapping(TypeModel model, String ns, ImportContext context, String dataType, XmlAttributes a, Boolean repeats, Boolean openModel, RecursionLimiter limiter) at System.Xml.Serialization.XmlReflectionImporter.ImportElement(TypeModel model, XmlRootAttribute root, String defaultNamespace, RecursionLimiter limiter) at System.Xml.Serialization.XmlReflectionImporter.ImportTypeMapping(Type type, XmlRootAttribute root, String defaultNamespace) at System.Xml.Serialization.XmlSerializer..ctor(Type type, String defaultNamespace) at System.Xml.Serialization.XmlSerializer..ctor(Type type) at eText.Common.Xml.Serialize[T](Object obj, Type[] extraTypes) in f:\TFS\New TFS\PDFReader\Posh.PdfReader.Win8\eText\Common\Utility.cs:line 81
at eText.Common.ApplicationSettings.<SaveDataToFileAsync>d__0
シリアル化に使用しているコード:
書籍クラス:
[DataContract]
public class Book : ViewModelBase
{
#region Constructor
/// <summary>
/// Initializes a new instance of the <see cref="Book" /> class.
/// </summary>
public Book(){}
/// <summary>
/// Initializes a new instance of the <see cref="Book" /> class.
/// </summary>
/// <param name="BookTitle">The book title.</param>
/// <param name="BookCategory">The book category.</param>
/// <param name="DownloadURL">The download URL.</param>
/// <param name="TotalNumberOfPages">The total number of pages.</param>
/// <param name="BookAuthor">The book author.</param>
/// <param name="ImageURL">The image URL.</param>
public Book(string BookTitle,string BookCategory,string DownloadURL, string TotalNumberOfPages, string BookAuthor, string ImageURL)
{
this.BookCategory = BookCategory;
this.BookTitle = BookTitle;
this.BookAuthor = BookAuthor;
this.TotalNumberOfPages = TotalNumberOfPages;
this.DownloadURL = DownloadURL;
this.ImageURL = ImageURL;
}
#endregion
}
BooksDownloadedData クラス
/// <summary>
/// Class to store downloaded books metaData
/// </summary>
[DataContract]
public class BooksDownloadedData
{
/// <summary>
/// The downloaded books detail
/// </summary>
[DataMember]
public Book DownloadedBooks { get; set; }
/// <summary>
/// Gets or sets a value indicating whether this instance is downloaded completed.
/// </summary>
/// <value>
/// <c>true</c> if this instance is downloaded completed; otherwise, <c>false</c>.
/// </value>
[DataMember]
public bool IsDownloadedCompleted { get; set; }
}
BooksDownloadedData の ObservableCollection を作成し、シリアル化後にローカル ストレージに保存しましたが、シリアル化時にエラーが発生しました。
// Create object to get the saved meta data of files
ObservableCollection<BooksDownloadedData> downLoadedFiles;
// Save the data to the local storage
await ApplicationSettings.SaveDataToFileAsync<ObservableCollection<BooksDownloadedData>>(fileName, downLoadedFiles);
public static async Task SaveDataToFileAsync<T>(string key, T value, bool roaming = false, Type[] extraTypes = null)
{
var file = roaming ? await ApplicationData.Current.RoamingFolder.CreateFileAsync(key + ".xml", CreationCollisionOption.ReplaceExisting) :
await ApplicationData.Current.LocalFolder.CreateFileAsync(key + ".xml", CreationCollisionOption.ReplaceExisting);
var xml = Xml.Serialize<T>(value, extraTypes);
await FileIO.WriteTextAsync(file, xml, UnicodeEncoding.Utf8);
}
public static string Serialize<T>(object obj, Type[] extraTypes = null)
{
using (var sw = new StringWriter())
{
var serializer = extraTypes == null ? new XmlSerializer(typeof(T)) : new XmlSerializer(typeof(T), extraTypes);
serializer.Serialize(sw, obj);
return sw.ToString();
}
}