为什么 System.TimeSpan 不是 XML 可序列化的？

Question

当我尝试将 TimeSpan 值存储到 ApplicationData 设置中时，我收到一个错误，因为 TimeSpan 无法序列化。这个 SO 问题显示了如何处理它：How to serialize a TimeSpan to XML

为什么 TimeSpan 不容易序列化？

还有，有不能序列化的数据类型列表吗？

Answer 1

它不会序列化的原因是XmlCustomFormatter没有实现序列化的功能。

来自XmlCustomFormatter 类，这里是支持的可序列化数据列表（来自FromDefaultValue 方法）：

DateTime

Date

Time

如果您查看源参考中的 XmlSerializationWriter 类，您可以看到它是如何用于序列化所有内容的：

请参阅WriteTypedPrimitive 方法以获取有关 primites 等的更多详细信息。

    /// <include file='doc\XmlSerializationWriter.uex' path='docs/doc[@for="XmlSerializationWriter.WriteTypedPrimitive"]/*' /> 
    protected void WriteTypedPrimitive(string name, string ns, object o, bool xsiType) {

关于对象和 xml 序列化的详细信息：

    /// <include file='doc\XmlSerializationWriter.uex' path='docs/doc[@for="XmlSerializationWriter.FromByteArrayBase64"]/*' /> 
    protected static byte[] FromByteArrayBase64(byte[] value) {
        // Unlike other "From" functions that one is just a place holder for automatic code generation. 
        // The reason is performance and memory consumption for (potentially) big 64base-encoded chunks
        // And it is assumed that the caller generates the code that will distinguish between byte[] and string return types
        //
        return value; 
    }

    /// <include file='doc\XmlSerializationWriter.uex' path='docs/doc[@for="XmlSerializationWriter.FromByteArrayHex"]/*' /> 
    protected static string FromByteArrayHex(byte[] value) {
        return XmlCustomFormatter.FromByteArrayHex(value); 
    } 

    /// <include file='doc\XmlSerializationWriter.uex' path='docs/doc[@for="XmlSerializationWriter.FromDateTime"]/*' /> 
    protected static string FromDateTime(DateTime value) {
        return XmlCustomFormatter.FromDateTime(value);
    }

    /// <include file='doc\XmlSerializationWriter.uex' path='docs/doc[@for="XmlSerializationWriter.FromDate"]/*' />
    protected static string FromDate(DateTime value) { 
        return XmlCustomFormatter.FromDate(value); 
    }

    /// <include file='doc\XmlSerializationWriter.uex' path='docs/doc[@for="XmlSerializationWriter.FromTime"]/*' />
    protected static string FromTime(DateTime value) {
        return XmlCustomFormatter.FromTime(value);
    } 

    /// <include file='doc\XmlSerializationWriter.uex' path='docs/doc[@for="XmlSerializationWriter.FromChar"]/*' /> 
    protected static string FromChar(char value) { 
        return XmlCustomFormatter.FromChar(value);
    } 

    /// <include file='doc\XmlSerializationWriter.uex' path='docs/doc[@for="XmlSerializationWriter.FromEnum"]/*' />
    protected static string FromEnum(long value, string[] values, long[] ids) {
        return XmlCustomFormatter.FromEnum(value, values, ids, null); 
    }

    /// <include file='doc\XmlSerializationWriter.uex' path='docs/doc[@for="XmlSerializationWriter.FromEnum1"]/*' /> 
    protected static string FromEnum(long value, string[] values, long[] ids, string typeName) {
        return XmlCustomFormatter.FromEnum(value, values, ids, typeName); 
    }

    /// <include file='doc\XmlSerializationWriter.uex' path='docs/doc[@for="XmlSerializationWriter.FromXmlName"]/*' />
    protected static string FromXmlName(string name) { 
        return XmlCustomFormatter.FromXmlName(name);
    } 

    /// <include file='doc\XmlSerializationWriter.uex' path='docs/doc[@for="XmlSerializationWriter.FromXmlNCName"]/*' />
    protected static string FromXmlNCName(string ncName) { 
        return XmlCustomFormatter.FromXmlNCName(ncName);
    }

    /// <include file='doc\XmlSerializationWriter.uex' path='docs/doc[@for="XmlSerializationWriter.FromXmlNmToken"]/*' /> 
    protected static string FromXmlNmToken(string nmToken) {
        return XmlCustomFormatter.FromXmlNmToken(nmToken); 
    } 

    /// <include file='doc\XmlSerializationWriter.uex' path='docs/doc[@for="XmlSerializationWriter.FromXmlNmTokens"]/*' /> 
    protected static string FromXmlNmTokens(string nmTokens) {
        return XmlCustomFormatter.FromXmlNmTokens(nmTokens);
    }