var settings = new XmlWriterSettings
{
    Indent = true,
    IndentChars = "  ",
    NewLineChars = "\n",
    Encoding = Encoding.UTF8
};
<p>using (var writer = XmlWriter.Create("output.xml", settings))
{
// 开始写入 XML 内容
}</p>

using (var writer = XmlWriter.Create("invoice.xml", settings))
{
    // 写入 XML 声明
    writer.WriteStartDocument();
<pre class='brush:php;toolbar:false;'>// 添加注释
writer.WriteComment("Generated invoice data");

// 写入根元素并声明命名空间
writer.WriteStartElement("Invoice");
writer.WriteAttributeString("xmlns", "inv", null, "http://example.com/invoice");
writer.WriteAttributeString("xmlns:xsi", null, "http://www.w3.org/2001/XMLSchema-instance");
writer.WriteAttributeString("xsi:schemaLocation", null,
    "http://example.com/invoice invoice.xsd");

// 写入头部信息
writer.WriteElementString("InvoiceNumber", "INV-2025-001");
writer.WriteElementString("IssueDate", DateTime.Today.ToString("yyyy-MM-dd"));

// 写入客户信息（嵌套元素）
writer.WriteStartElement("Customer");
writer.WriteAttributeString("type", "Retail");
writer.WriteElementString("Name", "张三");
writer.WriteElementString("Phone", "138-0000-0000");

writer.WriteStartElement("Address");
writer.WriteElementString("Street", "北京市朝阳区某街123号");
writer.WriteElementString("City", "北京");
writer.WriteElementString("Country", "中国");
writer.WriteEndElement(); // Address
writer.WriteEndElement(); // Customer

// 写入多个商品项
writer.WriteStartElement("Items");
var items = new[]
{
    new { Name = "笔记本电脑", Price = 8999.00, Qty = 1 },
    new { Name = "鼠标", Price = 199.00, Qty = 2 }
};

foreach (var item in items)
{
    writer.WriteStartElement("Item");
    writer.WriteAttributeString("id", Guid.NewGuid().ToString("N").Substring(0, 8));

    writer.WriteElementString("ProductName", item.Name);
    writer.WriteElementString("UnitPrice", item.Price.ToString("F2"));
    writer.WriteElementString("Quantity", item.Qty.ToString());
    writer.WriteElementString("Total", (item.Price * item.Qty).ToString("F2"));

    writer.WriteEndElement(); // Item
}
writer.WriteEndElement(); // Items

// 写入总计
writer.WriteStartElement("Totals");
writer.WriteElementString("Subtotal", "9397.00");
writer.WriteElementString("Tax", "1127.64");
writer.WriteElementString("GrandTotal", "10524.64");
writer.WriteEndElement(); // Totals

// 关闭根元素
writer.WriteEndElement();

// 写入结束文档（可选，Dispose 时会自动处理）
writer.WriteEndDocument();

}