无效操作异常，C# XML 错误

Posted 2023-03-31

【中文标题】无效操作异常，C# XML 错误

【英文标题】：Invalid operation exception , C# XML Error

【发布时间】：2017-06-21 04:27:39

【问题描述】：

嘿嘿，我正在为统一游戏制作一个插件（以下错误），所以我可能正在为我的主要插件制作这个插件并阅读排名。我不知道是什么错误，也没有看到任何关于此的帖子。这是我的错误：

[XmlArrayItem(ElementName = "Rank")]
public List<Rank> Ranks;
public void LoadDefaults()

    Ranks = new List<Rank>() 
    new Rank()  RankNumber = 0, GroupID = "Default" ,Messages = new List<Message>()  new Message("yo") , new Message("yo")
    ;

public class Rank

    public Rank()  

    public int RankNumber;
    public string GroupID;
    public List<Message> Messages;

public class Message

    public Message(string Rankmessage)  Rankmessage = RankMessage; 
    [XmlAttribute("RankMessage")]
    public string RankMessage;

错误：

[2/3/2017 7:47:23 PM] [Error] InvalidOperationException: RanksUnlocker.RanksUnlockerConfig+Message cannot be serialized because it does not have a default public constructor - System.Xml.Serialization.ReflectionHelper.CheckSerializableType (System.Type type, Boolean allowPrivateConstructors)
System.Xml.Serialization.XmlReflectionImporter.ImportClassMapping (System.Xml.Serialization.TypeData typeData, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace)
System.Xml.Serialization.XmlReflectionImporter.ImportTypeMapping (System.Xml.Serialization.TypeData typeData, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace)
Rethrow as InvalidOperationException: There was an error reflecting type 'RanksUnlocker.RanksUnlockerConfig+Message'.
System.Xml.Serialization.XmlReflectionImporter.ImportTypeMapping (System.Xml.Serialization.TypeData typeData, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace)
System.Xml.Serialization.XmlReflectionImporter.ImportTypeMapping (System.Type type, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace)
System.Xml.Serialization.XmlReflectionImporter.ImportListMapping (System.Xml.Serialization.TypeData typeData, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace, System.Xml.Serialization.XmlAttributes atts, Int32 nestingLevel)
System.Xml.Serialization.XmlReflectionImporter.ImportListMapping (System.Type type, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace, System.Xml.Serialization.XmlAttributes atts, Int32 nestingLevel)
System.Xml.Serialization.XmlReflectionImporter.CreateMapMember (System.Type declaringType, System.Xml.Serialization.XmlReflectionMember rmember, System.String defaultNamespace)
System.Xml.Serialization.XmlReflectionImporter.ImportClassMapping (System.Xml.Serialization.TypeData typeData, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace)
Rethrow as InvalidOperationException: There was an error reflecting field 'Messages'.
System.Xml.Serialization.XmlReflectionImporter.ImportClassMapping (System.Xml.Serialization.TypeData typeData, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace)
System.Xml.Serialization.XmlReflectionImporter.ImportTypeMapping (System.Xml.Serialization.TypeData typeData, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace)
Rethrow as InvalidOperationException: There was an error reflecting type 'RanksUnlocker.RanksUnlockerConfig+Rank'.
System.Xml.Serialization.XmlReflectionImporter.ImportTypeMapping (System.Xml.Serialization.TypeData typeData, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace)
System.Xml.Serialization.XmlReflectionImporter.ImportTypeMapping (System.Type type, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace)
System.Xml.Serialization.XmlReflectionImporter.ImportListMapping (System.Xml.Serialization.TypeData typeData, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace, System.Xml.Serialization.XmlAttributes atts, Int32 nestingLevel)
System.Xml.Serialization.XmlReflectionImporter.ImportListMapping (System.Type type, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace, System.Xml.Serialization.XmlAttributes atts, Int32 nestingLevel)
System.Xml.Serialization.XmlReflectionImporter.CreateMapMember (System.Type declaringType, System.Xml.Serialization.XmlReflectionMember rmember, System.String defaultNamespace)
System.Xml.Serialization.XmlReflectionImporter.ImportClassMapping (System.Xml.Serialization.TypeData typeData, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace)
Rethrow as InvalidOperationException: There was an error reflecting field 'Ranks'.
System.Xml.Serialization.XmlReflectionImporter.ImportClassMapping (System.Xml.Serialization.TypeData typeData, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace)
System.Xml.Serialization.XmlReflectionImporter.ImportTypeMapping (System.Xml.Serialization.TypeData typeData, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace)
Rethrow as InvalidOperationException: There was an error reflecting type 'RanksUnlocker.RanksUnlockerConfig'.
System.Xml.Serialization.XmlReflectionImporter.ImportTypeMapping (System.Xml.Serialization.TypeData typeData, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace)
System.Xml.Serialization.XmlReflectionImporter.ImportTypeMapping (System.Type type, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace)
System.Xml.Serialization.XmlSerializer..ctor (System.Type type, System.Xml.Serialization.XmlAttributeOverrides overrides, System.Type[] extraTypes, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace)
System.Xml.Serialization.XmlSerializer..ctor (System.Type type, System.Type[] extraTypes)
Rocket.Core.Assets.XMLFileAsset`1[RanksUnlocker.RanksUnlockerConfig]..ctor (System.String file, System.Type[] extraTypes, RanksUnlocker.RanksUnlockerConfig defaultInstance)
Rocket.Core.Plugins.RocketPlugin`1[RocketPluginConfiguration]..ctor ()
RanksUnlocker.RanksUnlocker..ctor ()
UnityEngine.GameObject:.ctor(String, Type[])
Rocket.Core.Plugins.RocketPluginManager:loadPlugins()
Rocket.Core.Plugins.RocketPluginManager:Start()

【问题讨论】：

错误是不言自明的。您的嵌套类型 RanksUnlocker.RanksUnlockerConfig+Message 必须有一个公共 无参数 构造函数。参见例如here。

【参考方案1】：

您需要向Message 类添加一个构造函数。它需要是public，并且需要接受零参数。

您已经拥有的现有构造函数对此不起作用，因为 XML 序列化过程不知道如何处理带参数的构造函数。您也可以保留现有的构造函数，只需添加一个不带参数的新构造函数。

【讨论】：

谢谢！我添加了 public Message()