.NET XML序列化陷阱？ [英] .NET XML serialization gotchas?

问题描述

我在做C＃XML序列化时遇到一些陷阱
我想我会分享：

I've run into a few gotchas when doing C# XML serialization that I thought I'd share:

• 您不能序列化是只读（如KeyValuePairs）项目


• 您不能序列化一个通用词典。相反，试试这个包装类（从<一个href=\"http://weblogs.asp.net/pwelter34/archive/2006/05/03/444961.aspx\">http://weblogs.asp.net/pwelter34/archive/2006/05/03/444961.aspx):

• You can't serialize items that are read-only (like KeyValuePairs)
• You can't serialize a generic dictionary. Instead, try this wrapper class (from http://weblogs.asp.net/pwelter34/archive/2006/05/03/444961.aspx):

using System;
using System.Collections.Generic;
using System.Text;
using System.Xml.Serialization;

[XmlRoot("dictionary")]
public class SerializableDictionary<TKey, TValue> : Dictionary<TKey, TValue>, IXmlSerializable
{      
    public System.Xml.Schema.XmlSchema GetSchema()
    {
        return null;
    }

    public void ReadXml(System.Xml.XmlReader reader)
    {
        XmlSerializer keySerializer = new XmlSerializer(typeof(TKey));
        XmlSerializer valueSerializer = new XmlSerializer(typeof(TValue));

        bool wasEmpty = reader.IsEmptyElement;
        reader.Read();

        if (wasEmpty)
            return;

        while (reader.NodeType != System.Xml.XmlNodeType.EndElement)
        {
            reader.ReadStartElement("item");

            reader.ReadStartElement("key");
            TKey key = (TKey)keySerializer.Deserialize(reader);
            reader.ReadEndElement();

            reader.ReadStartElement("value");
            TValue value = (TValue)valueSerializer.Deserialize(reader);
            reader.ReadEndElement();

            this.Add(key, value);

            reader.ReadEndElement();
            reader.MoveToContent();
        }
        reader.ReadEndElement();
    }

    public void WriteXml(System.Xml.XmlWriter writer)
    {
        XmlSerializer keySerializer = new XmlSerializer(typeof(TKey));
        XmlSerializer valueSerializer = new XmlSerializer(typeof(TValue));

        foreach (TKey key in this.Keys)
        {
            writer.WriteStartElement("item");

            writer.WriteStartElement("key");
            keySerializer.Serialize(writer, key);
            writer.WriteEndElement();

            writer.WriteStartElement("value");
            TValue value = this[key];
            valueSerializer.Serialize(writer, value);
            writer.WriteEndElement();

            writer.WriteEndElement();
        }
    }
}

任何其他的XML序列化的陷阱了吗？

Any other XML Serialization gotchas out there?

推荐答案

另一个巨大的疑难杂症：通过网页（ASP.NET）输出XML时，你不想包含的Uni$c$c字节顺序标记。当然，方式，使用或不使用BOM的几乎是相同的：

Another huge gotcha: when outputting XML through a web page (ASP.NET), you don't want to include the Unicode Byte-Order Mark. Of course, the ways to use or not use the BOM are almost the same:

XmlTextWriter wr = new XmlTextWriter(stream, new System.Text.Encoding.UTF8);

GOOD：

XmlTextWriter  wr = new XmlTextWriter(stream, new System.Text.UTF8Encoding(false))

您可以明确地传递false，表示你不想要的BOM。注意之间的明确，明显的区别 Encoding.UTF8 和 UTF8Encoding 。

You can explicitly pass false to indicate you don't want the BOM. Notice the clear, obvious difference between Encoding.UTF8 and UTF8Encoding.

在三个额外的BOM字节的开头是：（0xEFBBBF）或（239 187 191）。

The three extra BOM Bytes at the beginning are (0xEFBBBF) or (239 187 191).

参考：<一href=\"http://chrislaco.com/blog/troubleshooting-common-problems-with-the-xmlserializer/\">http://chrislaco.com/blog/troubleshooting-common-problems-with-the-xmlserializer/

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