c# - .NET XML 序列化错误(反射(reflect)类型错误)

Question

是的，我知道非常通用的标题，但我现在要解释一下。

鉴于下面的类定义，有人可以解释为什么我在调用 Serialize() 方法时会收到此异常。

{“反射(reflect)类型 'FNM.MISMO_3_0.FOREIGN_OBJECT' 时出现错误。”

{“选择标识符‘ItemsElementName’的类型与‘Items’的类型不一致。请使用 System.Collections.Generic.List 数组`1[[MISMO_3_0.ItemsChoiceType, MISMO_3_0, Version=1.0.0.0, Culture=中性，PublicKeyToken=null]]。"

谢谢，斯蒂芬

[System.CodeDom.Compiler.GeneratedCodeAttribute("System.Xml", "4.0.30319.225")]
[System.SerializableAttribute()]
[System.Diagnostics.DebuggerStepThroughAttribute()]
[System.ComponentModel.DesignerCategoryAttribute("code")]
[System.Xml.Serialization.XmlTypeAttribute(Namespace = "http://www.mismo.org/residential/2009/schemas")]
[System.Xml.Serialization.XmlRootAttribute(Namespace = "http://www.mismo.org/residential/2009/schemas", IsNullable = true)]
public partial class FOREIGN_OBJECT
{

    private List<object> itemsField;

    private List<ItemsChoiceType> itemsElementNameField;

    private MISMOresourceLink typeField;

    private bool typeFieldSpecified;

    private string roleField;

    private string titleField;

    private string labelField;

    private string sequenceNumberField;

    private static System.Xml.Serialization.XmlSerializer serializer;

    public FOREIGN_OBJECT()
    {
        this.itemsElementNameField = new List<ItemsChoiceType>();
        this.itemsField = new List<object>();
    }

    [System.Xml.Serialization.XmlElementAttribute("CharacterEncodingSetType", typeof(CharacterEncodingSetEnum), Order = 0)]
    [System.Xml.Serialization.XmlElementAttribute("CharacterEncodingSetTypeOtherDescription", typeof(MISMOString), Order = 0)]
    [System.Xml.Serialization.XmlElementAttribute("EXTENSION", typeof(EXTENSION), Order = 0)]
    [System.Xml.Serialization.XmlElementAttribute("EmbeddedContentXML", typeof(MISMOXML), Order = 0)]
    [System.Xml.Serialization.XmlElementAttribute("MIMETypeIdentifier", typeof(MISMOIdentifier), Order = 0)]
    [System.Xml.Serialization.XmlElementAttribute("ObjectCreatedDatetime", typeof(MISMODatetime), Order = 0)]
    [System.Xml.Serialization.XmlElementAttribute("ObjectDescription", typeof(MISMOString), Order = 0)]
    [System.Xml.Serialization.XmlElementAttribute("ObjectEncodingType", typeof(ObjectEncodingEnum), Order = 0)]
    [System.Xml.Serialization.XmlElementAttribute("ObjectEncodingTypeOtherDescription", typeof(MISMOString), Order = 0)]
    [System.Xml.Serialization.XmlElementAttribute("ObjectName", typeof(MISMOString), Order = 0)]
    [System.Xml.Serialization.XmlElementAttribute("ObjectURI", typeof(string), DataType = "anyURI", Order = 0)]
    [System.Xml.Serialization.XmlElementAttribute("OriginalCreatorDigestValue", typeof(MISMOValue), Order = 0)]
    [System.Xml.Serialization.XmlElementAttribute("REFERENCE", typeof(REFERENCE), Order = 0)]
    [System.Xml.Serialization.XmlChoiceIdentifierAttribute("ItemsElementName")]
    public List<object> Items
    {
        get
        {
            return this.itemsField;
        }
        set
        {
            this.itemsField = value;
        }
    }

    [System.Xml.Serialization.XmlElementAttribute("ItemsElementName", Order = 1)]
    [System.Xml.Serialization.XmlIgnoreAttribute()]
    public List<ItemsChoiceType> ItemsElementName
    {
        get
        {
            return this.itemsElementNameField;
        }
        set
        {
            this.itemsElementNameField = value;
        }
    }

    [System.Xml.Serialization.XmlAttributeAttribute(Form = System.Xml.Schema.XmlSchemaForm.Qualified, Namespace = "http://www.w3.org/1999/xlink")]
    public MISMOresourceLink type
    {
        get
        {
            return this.typeField;
        }
        set
        {
            this.typeField = value;
        }
    }

    [System.Xml.Serialization.XmlIgnoreAttribute()]
    public bool typeSpecified
    {
        get
        {
            return this.typeFieldSpecified;
        }
        set
        {
            this.typeFieldSpecified = value;
        }
    }

    [System.Xml.Serialization.XmlAttributeAttribute(Form = System.Xml.Schema.XmlSchemaForm.Qualified, Namespace = "http://www.w3.org/1999/xlink")]
    public string role
    {
        get
        {
            return this.roleField;
        }
        set
        {
            this.roleField = value;
        }
    }

    [System.Xml.Serialization.XmlAttributeAttribute(Form = System.Xml.Schema.XmlSchemaForm.Qualified, Namespace = "http://www.w3.org/1999/xlink")]
    public string title
    {
        get
        {
            return this.titleField;
        }
        set
        {
            this.titleField = value;
        }
    }

    [System.Xml.Serialization.XmlAttributeAttribute(Form = System.Xml.Schema.XmlSchemaForm.Qualified, Namespace = "http://www.w3.org/1999/xlink", DataType = "NMTOKEN")]
    public string label
    {
        get
        {
            return this.labelField;
        }
        set
        {
            this.labelField = value;
        }
    }

    [System.Xml.Serialization.XmlAttributeAttribute(DataType = "integer")]
    public string SequenceNumber
    {
        get
        {
            return this.sequenceNumberField;
        }
        set
        {
            this.sequenceNumberField = value;
        }
    }

    private static System.Xml.Serialization.XmlSerializer Serializer
    {
        get
        {
            if ((serializer == null))
            {
                serializer = new System.Xml.Serialization.XmlSerializer(typeof(FOREIGN_OBJECT));
            }
            return serializer;
        }
    }

    #region Serialize/Deserialize
    /// <summary>
    /// Serializes current FOREIGN_OBJECT object into an XML document
    /// </summary>
    /// <returns>string XML value</returns>
    public virtual string Serialize(System.Text.Encoding encoding)
    {
        System.IO.StreamReader streamReader = null;
        System.IO.MemoryStream memoryStream = null;
        try
        {
            memoryStream = new System.IO.MemoryStream();
            System.Xml.XmlWriterSettings xmlWriterSettings = new System.Xml.XmlWriterSettings();
            xmlWriterSettings.Encoding = encoding;
            System.Xml.XmlWriter xmlWriter = XmlWriter.Create(memoryStream, xmlWriterSettings);
            Serializer.Serialize(xmlWriter, this);
            memoryStream.Seek(0, System.IO.SeekOrigin.Begin);
            streamReader = new System.IO.StreamReader(memoryStream);
            return streamReader.ReadToEnd();
        }
        finally
        {
            if ((streamReader != null))
            {
                streamReader.Dispose();
            }
            if ((memoryStream != null))
            {
                memoryStream.Dispose();
            }
        }
    }

    public virtual string Serialize()
    {
        return Serialize(Encoding.UTF8);
    }

    /// <summary>
    /// Deserializes workflow markup into an FOREIGN_OBJECT object
    /// </summary>
    /// <param name="xml">string workflow markup to deserialize</param>
    /// <param name="obj">Output FOREIGN_OBJECT object</param>
    /// <param name="exception">output Exception value if deserialize failed</param>
    /// <returns>true if this XmlSerializer can deserialize the object; otherwise, false</returns>
    public static bool Deserialize(string xml, out FOREIGN_OBJECT obj, out System.Exception exception)
    {
        exception = null;
        obj = default(FOREIGN_OBJECT);
        try
        {
            obj = Deserialize(xml);
            return true;
        }
        catch (System.Exception ex)
        {
            exception = ex;
            return false;
        }
    }

    public static bool Deserialize(string xml, out FOREIGN_OBJECT obj)
    {
        System.Exception exception = null;
        return Deserialize(xml, out obj, out exception);
    }

    public static FOREIGN_OBJECT Deserialize(string xml)
    {
        System.IO.StringReader stringReader = null;
        try
        {
            stringReader = new System.IO.StringReader(xml);
            return ((FOREIGN_OBJECT)(Serializer.Deserialize(System.Xml.XmlReader.Create(stringReader))));
        }
        finally
        {
            if ((stringReader != null))
            {
                stringReader.Dispose();
            }
        }
    }

    /// <summary>
    /// Serializes current FOREIGN_OBJECT object into file
    /// </summary>
    /// <param name="fileName">full path of outupt xml file</param>
    /// <param name="exception">output Exception value if failed</param>
    /// <returns>true if can serialize and save into file; otherwise, false</returns>
    public virtual bool SaveToFile(string fileName, System.Text.Encoding encoding, out System.Exception exception)
    {
        exception = null;
        try
        {
            SaveToFile(fileName, encoding);
            return true;
        }
        catch (System.Exception e)
        {
            exception = e;
            return false;
        }
    }

    public virtual bool SaveToFile(string fileName, out System.Exception exception)
    {
        return SaveToFile(fileName, Encoding.UTF8, out exception);
    }

    public virtual void SaveToFile(string fileName)
    {
        SaveToFile(fileName, Encoding.UTF8);
    }

    public virtual void SaveToFile(string fileName, System.Text.Encoding encoding)
    {
        System.IO.StreamWriter streamWriter = null;
        try
        {
            string xmlString = Serialize(encoding);
            streamWriter = new System.IO.StreamWriter(fileName, false, Encoding.UTF8);
            streamWriter.WriteLine(xmlString);
            streamWriter.Close();
        }
        finally
        {
            if ((streamWriter != null))
            {
                streamWriter.Dispose();
            }
        }
    }

    /// <summary>
    /// Deserializes xml markup from file into an FOREIGN_OBJECT object
    /// </summary>
    /// <param name="fileName">string xml file to load and deserialize</param>
    /// <param name="obj">Output FOREIGN_OBJECT object</param>
    /// <param name="exception">output Exception value if deserialize failed</param>
    /// <returns>true if this XmlSerializer can deserialize the object; otherwise, false</returns>
    public static bool LoadFromFile(string fileName, System.Text.Encoding encoding, out FOREIGN_OBJECT obj, out System.Exception exception)
    {
        exception = null;
        obj = default(FOREIGN_OBJECT);
        try
        {
            obj = LoadFromFile(fileName, encoding);
            return true;
        }
        catch (System.Exception ex)
        {
            exception = ex;
            return false;
        }
    }

    public static bool LoadFromFile(string fileName, out FOREIGN_OBJECT obj, out System.Exception exception)
    {
        return LoadFromFile(fileName, Encoding.UTF8, out obj, out exception);
    }

    public static bool LoadFromFile(string fileName, out FOREIGN_OBJECT obj)
    {
        System.Exception exception = null;
        return LoadFromFile(fileName, out obj, out exception);
    }

    public static FOREIGN_OBJECT LoadFromFile(string fileName)
    {
        return LoadFromFile(fileName, Encoding.UTF8);
    }

    public static FOREIGN_OBJECT LoadFromFile(string fileName, System.Text.Encoding encoding)
    {
        System.IO.FileStream file = null;
        System.IO.StreamReader sr = null;
        try
        {
            file = new System.IO.FileStream(fileName, FileMode.Open, FileAccess.Read);
            sr = new System.IO.StreamReader(file, encoding);
            string xmlString = sr.ReadToEnd();
            sr.Close();
            file.Close();
            return Deserialize(xmlString);
        }
        finally
        {
            if ((file != null))
            {
                file.Dispose();
            }
            if ((sr != null))
            {
                sr.Dispose();
            }
        }
    }
    #endregion

    #region Clone method
    /// <summary>
    /// Create a clone of this FOREIGN_OBJECT object
    /// </summary>
    public virtual FOREIGN_OBJECT Clone()
    {
        return ((FOREIGN_OBJECT)(this.MemberwiseClone()));
    }
    #endregion
}

Answer 1

XmlChoiceIdentifierAttribute 中的多个元素仅在 ChoiceIdentifier 是数组而不是通用列表时才受支持。

[System.Xml.Serialization.XmlElementAttribute("ItemsElementName", Order = 1)]
[System.Xml.Serialization.XmlIgnoreAttribute()]
public ItemsChoiceType[] ItemsElementName
{
    // ...
}

该错误令人困惑，因为它假设 Items 是类数组(列表)并且您选择的标识符不是数组，您在标识符选择的类型之前错过了数组限定符。但事实并非如此，因此该建议完全具有误导性。

注意:从理论上看代码(来自微软源服务器)Items 不需要是数组...实际上临时序列化类的生成完全爆炸，因为 List.Length 不是公开(已明确实现)