[英]How to deserialize from XML after adding an attribute?
我有一個與此類似的 class:
public class Script
{
public string Name { get; set; }
public string HomeKey { get; set; } = "";
}
這將從 XML 文件反序列化,如下所示:
<Script>
<Name>ScriptName</Name>
<HomeKey>KeyText</HomeKey>
</Script>
使用以下代碼可以正常工作:
[Test]
public void DeserializeScriptTest()
{
// Arrange
var contents = Helpers.LoadEmbeddedResourceFileContents("test.xml");
var serializer = new XmlSerializer(typeof(Script));
Script s;
// Act
using (var reader = new StringReader(contents))
{
s = (Script)serializer.Deserialize(reader);
}
// Assert
Assert.AreEqual("KeyText", s.HomeKey);
}
而且我有很多使用這些文件的客戶端代碼,並且將來會繼續使用它們。
現在我的 XML 文件略有變化,如下所示:
<Script>
<Name>ScriptName</Name>
<HomeKey KeyId="12345">KeyText</HomeKey>
</Script>
我的老客戶應該仍然能夠反序列化這個文件,因為舊的 HomeKey 仍然在同一個地方。 新客戶端也需要反序列化屬性值。 所以我創建了一個新的 class:
public class ScriptV2 : Script
{
public new HomeKeyV2 HomeKey { get; set; } = new HomeKeyV2();
}
public class HomeKeyV2
{
[XmlAttribute]
public int KeyId { get; set; }
[XmlText]
public string Value { get; set; } = "";
}
舊代碼適用於新文件就好了。 但是,新代碼不起作用。
當我運行這個:
[Test]
public void DeserializeScriptV2Test()
{
// Arrange
var contents = Helpers.LoadEmbeddedResourceFileContents("test.xml");
var serializer = new XmlSerializer(typeof(ScriptV2), new XmlRootAttribute("Script")); // <-- Exception here
ScriptV2 s;
// Act
using (var reader = new StringReader(contents))
{
s = (ScriptV2)serializer.Deserialize(reader);
}
// Assert
Assert.AreEqual("KeyText", s.HomeKey.Value);
}
我在標記線上遇到異常:
System.InvalidOperationException
HResult=0x80131509
Message=There was an error reflecting type 'Project.Classes.ScriptV2'.
Source=System.Xml
StackTrace:
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, XmlAttributeOverrides overrides, Type[] extraTypes, XmlRootAttribute root, String defaultNamespace, String location, Evidence evidence)
at System.Xml.Serialization.XmlSerializer..ctor(Type type, XmlRootAttribute root)
at Project.Tests.DeserializeScriptV2Test() in foobarTests.cs:line 12
Inner Exception 1:
InvalidOperationException: There was an error reflecting property 'HomeKey'.
Inner Exception 2:
InvalidOperationException: Member ScriptV2.HomeKey of type Project.Classes.HomeKeyV2 hides base class member Script.HomeKey of type System.String. Use XmlElementAttribute or XmlAttributeAttribute to specify a new name.
如何更改 ScriptV2 以使其與 xml 文件的新結構一起使用? 我無法更改 Script.cs 或將更新的代碼部署到舊客戶端。 他們都可以正常使用更改后的 XML 文件。
這對我有用
[XmlRoot(ElementName = "HomeKey")]
public class HomeKey
{
[XmlAttribute(AttributeName = "KeyId")]
public string KeyId { get; set; }
[XmlText]
public string Text { get; set; }
}
[XmlRoot(ElementName = "Script")]
public class ScriptV2
{
[XmlElement(ElementName = "Name")]
public string Name { get; set; }
[XmlElement(ElementName = "HomeKey")]
public HomeKey HomeKey { get; set; }
}
用法
var contents = "<Script>\r\n <Name>ScriptName</Name>\r\n <HomeKey KeyId=\"12345\">KeyText</HomeKey>\r\n</Script>";
var serializer = new XmlSerializer(typeof(ScriptV2), new XmlRootAttribute("Script"));
using (var reader = new StringReader(contents))
{
var s = (ScriptV2)serializer.Deserialize(reader);
}
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