反序列化到子类的问题
本文关键字：问题 子类 反序列化 | 更新日期: 2023-09-27 17:50:32
我一直在尝试将一些XML反序列化为一个类，该类是另一个类的子类。当我尝试反序列化到基类时，它工作了。然而，当类被反序列化到任何子类时，它将失败。
我想知道为什么会这样。这是否违反了OOP设计，或者我只是遗漏了一些东西。由于
代码如下:
基类:Shape.cs
namespace Shape
{
using System.Xml.Serialization;
/// <remarks/>
[System.CodeDom.Compiler.GeneratedCodeAttribute("xsd", "4.0.30319.1")]
[System.SerializableAttribute()]
[System.Diagnostics.DebuggerStepThroughAttribute()]
[System.ComponentModel.DesignerCategoryAttribute("code")]
[System.Xml.Serialization.XmlTypeAttribute(AnonymousType = true)]
[System.Xml.Serialization.XmlRootAttribute(IsNullable = false)]
[KnownType(typeof(Rectangle))]
[KnownType(typeof(Square))]
public partial class Shape
{
private string widthField;
private string heightField;
private string colorField;
/// <remarks/>
[System.Xml.Serialization.XmlElementAttribute(Form = System.Xml.Schema.XmlSchemaForm.Unqualified)]
public string Width
{
get
{
return this.widthField;
}
set
{
this.widthField = value;
}
}
/// <remarks/>
[System.Xml.Serialization.XmlElementAttribute(Form = System.Xml.Schema.XmlSchemaForm.Unqualified)]
public string Height
{
get
{
return this.heightField;
}
set
{
this.heightField = value;
}
}
/// <remarks/>
[System.Xml.Serialization.XmlElementAttribute(Form = System.Xml.Schema.XmlSchemaForm.Unqualified)]
public string Color
{
get
{
return this.colorField;
}
set
{
this.colorField = value;
}
}
}
/// <remarks/>
[System.CodeDom.Compiler.GeneratedCodeAttribute("xsd", "4.0.30319.1")]
[System.SerializableAttribute()]
[System.Diagnostics.DebuggerStepThroughAttribute()]
[System.ComponentModel.DesignerCategoryAttribute("code")]
[System.Xml.Serialization.XmlTypeAttribute(AnonymousType = true)]
[System.Xml.Serialization.XmlRootAttribute(Namespace = "", IsNullable = false)]
public partial class NewDataSet
{
private Shape[] itemsField;
/// <remarks/>
[System.Xml.Serialization.XmlElementAttribute("Shape")]
public Shape[] Items
{
get
{
return this.itemsField;
}
set
{
this.itemsField = value;
}
}
}
}
子类#1:Rectangle.cs
namespace Shape
{
public class Rectangle : Shape
{
}
}
子类#2:Square.cs
namespace Shape
{
public class Square : Shape
{
}
}
试图将XML反序列化为矩形(子类#1)的类
string xmlSample = "<?xml version='"1.0'" ?><Shape xmlns:xs='"http://www.w3.org/2001/XMLSchema'"><Width>2</Width><Height>5</Height><Color>Red</Color></Shape>";
//Shape.Shape shape = Utilities.ByteArrayToObject<Shape.Shape>(Utilities.XmlStringToBytes(xmlSample)); <-- Works OK
Shape.Rectangle rect = Utilities.ByteArrayToObject<Shape.Rectangle>(Utilities.XmlStringToBytes(xmlSample)); //<-- Will fail
<?xml version="1.0" encoding="utf-8"?>
<xs:schema id="NewDataSet" xmlns="" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
<xs:element name="Shape">
<xs:complexType>
<xs:sequence>
<xs:element name="Width" type="xs:string" minOccurs="0" />
<xs:element name="Height" type="xs:string" minOccurs="0" />
<xs:element name="Color" type="xs:string" minOccurs="0" />
</xs:sequence>
</xs:complexType>
</xs:element>
<xs:element name="NewDataSet" msdata:IsDataSet="true" msdata:UseCurrentLocale="true">
<xs:complexType>
<xs:choice minOccurs="0" maxOccurs="unbounded">
<xs:element ref="Shape" />
</xs:choice>
</xs:complexType>
</xs:element>
</xs:schema>
见下面的代码。我发现了一些问题。一个XML只能有一个根节点，但是您有一个Shape[]数组作为根节点。所以我添加到你的xml NewDataSet。类中对象的名称与xml中的标记不匹配。因此，我将XmlElement添加到类中。我还将XmlAttribute更改为XmlElement。XML属性在XML中有一个等号。在尖括号之间的Xml中有TEXT。
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml;
using System.Xml.Serialization;
using System.IO;
using System.Data;
namespace Shape
{
class Program
{
static void Main(string[] args)
{
string xmlSample = "<?xml version='"1.0'"?><NewDataSet xmlns:xsi='"http://www.w3.org/2001/XMLSchema-instance'" xmlns:xsd='"http://www.w3.org/2001/XMLSchema'"><Shape xsi:type='"Rectangle'"><Width>2</Width><Height>5</Height><Color>Red</Color></Shape></NewDataSet>";
StringReader reader = new StringReader(xmlSample);
XmlSerializer xs = new XmlSerializer(typeof(NewDataSet));
NewDataSet ds = (NewDataSet)xs.Deserialize(reader);
}
}
/// <remarks/>
[System.CodeDom.Compiler.GeneratedCodeAttribute("xsd", "4.0.30319.1")]
[System.SerializableAttribute()]
[System.Diagnostics.DebuggerStepThroughAttribute()]
[System.ComponentModel.DesignerCategoryAttribute("code")]
[System.Xml.Serialization.XmlTypeAttribute(AnonymousType = true)]
[XmlInclude(typeof(Rectangle))]
[XmlInclude(typeof(Square))]
[XmlRoot("Shape")]
public partial class Shape
{
private string widthField;
private string heightField;
private string colorField;
/// <remarks/>
[XmlElement("Width")]
public string Width
{
get
{
return this.widthField;
}
set
{
this.widthField = value;
}
}
/// <remarks/>
[XmlElement("Height")]
public string Height
{
get
{
return this.heightField;
}
set
{
this.heightField = value;
}
}
/// <remarks/>
[XmlElement("Color")]
public string Color
{
get
{
return this.colorField;
}
set
{
this.colorField = value;
}
}
}
[XmlRoot("Rectangle")]
public class Rectangle : Shape
{
}
[XmlRoot("Square")]
public class Square : Shape
{
}
/// <remarks/>
[System.CodeDom.Compiler.GeneratedCodeAttribute("xsd", "4.0.30319.1")]
[System.SerializableAttribute()]
[System.Diagnostics.DebuggerStepThroughAttribute()]
[System.ComponentModel.DesignerCategoryAttribute("code")]
[System.Xml.Serialization.XmlTypeAttribute(AnonymousType = true)]
//[System.Xml.Serialization.XmlRootAttribute(Namespace = "", IsNullable = false)]
[XmlRoot("NewDataSet")]
public partial class NewDataSet
{
private Shape[] itemsField;
/// <remarks/>
[XmlElement("Shape")]
public Shape[] Items
{
get
{
return this.itemsField;
}
set
{
this.itemsField = value;
}
}
}
}
找到了解决方案。修复是添加一个[XmlRoot("Shape")]到子类修复这个问题。
的例子:
[XmlRoot("Shape")]
public class Rectangle : Shape
{ .. }
对于'Square'类也是一样
转换为基类型在c#中被认为是安全的隐式类型转换。