基于C#中XmlWriter写入Xml的深入分析

假定创建了xmlwriter的实例变量xmlwriter，下文中将使用此实例变量写xml
1.如何使用xmlwriter写xml文档声明

// writestartdocument方法可以接受一个bool参数（表示standalone，是否为独立文档）或者不指定参数standalone保持默认值
xmlwriter.writestartdocument(false|true);

注意在使用writestartdocument方法后最好调用xmlwrite.writeenddocument()方法来关闭所有可能未关闭标签
2.如何使用xmlwriter写xml节点以及属性

//写节点
xmlwriter.writestartelement("cat");
//给节点添加属性
xmlwriter.writeattributestring("color", "white");
//给节点内部添加文本
xmlwriter.writestring("i'm a cat");
xmlwriter.writeendelement();

或者通过writeelementstring(string,string)方法写xml节点同时写下节点值，如下

//通过writeelementstring可以添加一个节点同时添加节点内容
xmlwriter.writeelementstring("pig", "pig is great");

3.如何写cdata

xmlwriter.writestartelement("dog");
//写cdata
xmlwriter.writecdata("<strong>dog is dog</strong>");
xmlwriter.writeendelement();

4.如何使用xmlwriter添加注释

xmlwriter.writecomment("this is an example writed by //www.jb51.net ");

5.如何设置xmlwriter的输出格式，解决输出utf-16问题
设置xml输出格式，需要通过xmlwritersettings类，如下代码

xmlwritersettings settings = new xmlwritersettings();
//要求缩进
settings.indent = true;
//注意如果不设置encoding默认将输出utf-16
//注意这儿不能直接用encoding.utf8如果用encoding.utf8将在输出文本的最前面添加4个字节的非xml内容
settings.encoding = new utf8encoding(false);

//设置换行符
settings.newlinechars = environment.newline;

完整的代码示例如下：

using system;
using system.collections.generic;
using system.text;
using system.io;
using system.xml;

namespace usexmlwriter
{
    class program
    {
        static void main(string[] args)
        {
            using (memorystream ms = new memorystream())
            {
                xmlwritersettings settings = new xmlwritersettings();
                //要求缩进
                settings.indent = true;
                //注意如果不设置encoding默认将输出utf-16
                //注意这儿不能直接用encoding.utf8如果用encoding.utf8将在输出文本的最前面添加4个字节的非xml内容
                settings.encoding = new utf8encoding(false);

                //设置换行符
                settings.newlinechars = environment.newline;

                using (xmlwriter xmlwriter = xmlwriter.create(ms, settings))
                {

                    //写xml文件开始<?xml version="1.0" encoding="utf-8" ?>
                    xmlwriter.writestartdocument(false);
                    //写根节点
                    xmlwriter.writestartelement("root");
                    //写字节点
                    xmlwriter.writestartelement("cat");
                    //给节点添加属性
                    xmlwriter.writeattributestring("color", "white");
                    //给节点内部添加文本
                    xmlwriter.writestring("i'm a cat");
                    xmlwriter.writeendelement();

 
                    //通过writeelementstring可以添加一个节点同时添加节点内容
                    xmlwriter.writeelementstring("pig", "pig is great");

 
                    xmlwriter.writestartelement("dog");
                    //写cdata
                    xmlwriter.writecdata("<strong>dog is dog</strong>");
                    xmlwriter.writeendelement();

                    xmlwriter.writecomment("this is an example writed by  //www.jb51.net ");

                    xmlwriter.writeendelement();
                    xmlwriter.writeenddocument();

                }

                //将xml内容输出到控制台中
                string xml = encoding.utf8.getstring(ms.toarray());
                console.writeline(xml);
            }
            console.read();

        }
    }
}