所以，我还是问到这个主题的问题： - （

So I am still asking questions about this topic :-(

所以，我创建了一个对象，用XML序列化装饰它的属性，从我所看到的我添加一个空的命名空间的XML序列化namepsace集合，以免让多余的属性，我也没打算有。

So I create an object, decorate it with the Xml Serialization Attributes, from what I have seen I add an empty namespace to the xml serialization namepsace collections so as not to get the superfluous attributes I did not intend to have.

编辑：我的意思是属性是这些：

The attribute I mean are these:

<url xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"; xmlns:xsd="http://www.w3.org/2001/XMLSchema"; xmlns="">

所以这给了我两个额外的属性。

so it gives me two extra attributes.

如果我更改文档的开头从经过进一步调查：**

After further investigation if I change the beginning of the document from:**

writer.WriteStartElement("urlset","http://www.sitemaps.org/schemas/sitemap/0.9");

到

writer.WriteStartElement("urlset");

**然后，我没有得到空的xmlns =属性中的URL标记。这是伟大的，但我确实需要的根元素具有的xmlns =htt​​p://www.sitemaps.org/schemas/sitemap/0.9，即：

<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">

但我仍然得到一个空的的xmlns =中的序列化类型属性。

But I still get an empty xmlns="" attribute in the serialized type.

[XmlRoot(ElementName = "url", Namespace="")]
public class SitemapNode
{
    [XmlElement(ElementName = "loc")]
    public string Location { get; set; }
    [XmlElement(ElementName = "lastmod")]
    public DateTime LastModified { get; set; }
    [XmlElement(ElementName = "changefreq")]
    public SitemapChangeFrequency ChangeFrequency { get; set; }
    [XmlElement(ElementName = "priority")]
    public decimal Priority { get; set; }

    public SitemapNode()
    {
        Location = String.Empty;
        LastModified = DateTime.Now;
        ChangeFrequency = SitemapChangeFrequency.monthly;
        Priority = 0.5M;
    }

    public SitemapNode(string location, DateTime lastModified, SitemapChangeFrequency changeFrequency, decimal priority)
    {
        Location = location;
        LastModified = lastModified;
        ChangeFrequency = changeFrequency;
        Priority = priority;
    }
}

然后我用下面的追加到我的XmlWriter：

Then I use the following to append to my XmlWriter:

foreach (uk.co.andrewrea.SitemapNode node in List)
{
    XmlSerializerNamespaces ns = new XmlSerializerNamespaces();
    ns.Add(String.Empty, String.Empty);
    Serializer.Serialize(Writer, node, ns);
}

这工作了罚款只是我留下的EMPTY的的xmlns =像这样

This works out fine except I am left with an emtpy xmlns="" like this

<url xmlns="">

任何人任何想法？再次，我可以用的XmlTextWriter和XmlDocument的做到这一点，但我需要用的XmlWriter去实现它。

Anyone any ideas? Again I can achieve this using the XmlTextWriter and the XmlDocument but I need to achieve it using the XmlWriter.

任何帮助是极大的AP preciated。

Any help is greatly appreciated.

推荐答案

这工作（你只需要他们在同一个命名空间和使用命名空间类，以便在writter不会混淆）：

This works (you just need them to be in the same namespace and you use the namespaces class so the writter doesn't confuse):

[TestMethod]
public void TestMethod3()
{
    var list = new []{new SitemapNode("1", DateTime.Now, 1), new SitemapNode("2", DateTime.Now.AddDays(1), 2)};
    var serializer = new XmlSerializer(typeof(SitemapNode));
    var st = new MemoryStream();
    using (var writer = XmlWriter.Create(st))
    {
        var ns = new XmlSerializerNamespaces();
        ns.Add("", "test");
        writer.WriteStartElement("test", "test");
        foreach (SitemapNode node in list)
        {
            serializer.Serialize(writer, node, ns);
        }
        writer.WriteEndElement();
    }
    st.Position = 0;
    TestContext.WriteLine(new StreamReader(st).ReadToEnd());
}


[XmlRoot(ElementName = "url", Namespace = "test")]
public class SitemapNode
{
    [XmlElement(ElementName = "loc")]
    public string Location { get; set; }
    [XmlElement(ElementName = "lastmod")]
    public DateTime LastModified { get; set; }
    [XmlElement(ElementName = "priority")]
    public decimal Priority { get; set; }

    public SitemapNode()
    {
        Location = String.Empty;
        LastModified = DateTime.Now;
        Priority = 0.5M;
    }

    public SitemapNode(string location, DateTime lastModified, decimal priority)
    {
        Location = location;
        LastModified = lastModified;
        Priority = priority;
    }
}

和输出（根据您的意见，这就是你要找的人）：

And the output is (based on your comments that is what you were looking for):

    <?xml version="1.0" encoding="utf-8"?><test xmlns="test">
<url><loc>1</loc><lastmod>2009-03-05T13:35:54.6468-07:00</lastmod><priority>1</priority></url>
<url><loc>2</loc><lastmod>2009-03-06T13:35:54.6478-07:00</lastmod><priority>2</priority></url></test>