我正在尝试序列化ObservableCollection。但我收到以下错误：请告诉我如何解决这个问题？
错误：
{System.InvalidOperationException：反映类型时出错 ＆＃39; {System.Collections.ObjectModel.ObservableCollection {1}} 1.MoveNext（） 在f：\ TFS \ New TFS \ PDFReader \ Posh.PdfReader.Win8 \ ETEXT \ COMMON \ ApplicationSettings.cs：行 16 ---从抛出异常的先前位置开始的堆栈跟踪结束--- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess（任务 任务） System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification（任务 任务）在System.Runtime.CompilerServices.TaskAwaiter.GetResult（）
在eText.ViewModel.MainViewModel.d__a.MoveNext（）中 F：\ TFS \新 TFS \ PDFReader \ Posh.PdfReader.Win8 \ ETEXT \视图模型\ MainViewModel.cs：行 268}
我用于序列化的代码：
书籍课程：
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__0BooksDownloadedData类
[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
}
为BooksDownloadedData创建一个ObservableCollection，然后在序列化后将其保存在本地存储中，但在序列化时出现错误：
/// <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; }
}
答案 0 :(得分：3)
从堆栈跟踪中我看到：
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.
XmlSerializer类的limitations之一是被序列化的类必须具有无参数构造函数。
您是否可以使用DataContractSerializer？
答案 1 :(得分：2)
问题在于Windows.Storage.StorageFile的使用，这显然不适合与序列化（或至少：不是XmlSerializer）。
您可能能够重构您的模型，因此您无需使用StorageFile。您可能能够使用DownloadedBookFileDetails标记该成员（[XmlIgnore]），并在反序列化后手动重新创建StorageFile。您可能能够使用不同的序列化程序（DataContractSerializer，JSON.NET，protobuf-net等）。
然而！在大多数情况下，我看到（并且我经常处理序列化）人们犯的关键错误是试图对抗序列化程序，以便他们可以继续使用现有的域模型。实际上，最简单要做的事情通常是：创建DTO ：一个单独的模型，专门用于表示数据作为序列化的桥梁，然后映射到/来自DTO模型和您的主域模型。
这不仅每次非常容易，而且如果你想要的话，它也会让你处于非常有利的位置：