删除XML节点集合中的空/空白元素

Question

我有一个像这样的XML文档:

<magento_api>
    <data_item>
        <code>400</code>
        <message>Attribute weight is not applicable for product type Configurable Product</message>
    </data_item>
    <data_item>
        <code>400</code>
        <message>Resource data pre-validation error.</message>
    </data_item>
    <data_item>
        <code>1</code>
        <message></message>
    </data_item>
    <data_item>
        <code></code>
        <message>No code was given</message>
    </data_item>
</magento_api>

我正在尝试迭代每个节点并执行以下操作:

1. 扔掉任何空/空白的元素.
2. 仅使用包含值的元素生成新节点.
3. 将生成的文档发送到不同的Web服务.

我正在努力的部分是如何遍历每个节点并检查每个元素的空值.

我一直在http://rextester.com/runco​​de上测试这段代码,但似乎无法弄清楚:

Console.WriteLine("Querying tree loaded with XElement.Load");
Console.WriteLine("----");
XElement doc = XElement.Parse(@"<magento_api>
          <data_item>
            <code>400</code>
            <message>Attribute weight is not applicable for product type Configurable Product</message>
          </data_item>
          <data_item>
            <code>400</code>
            <message>Resource data pre-validation error.</message>
          </data_item>
          <data_item>
            <code>1</code>
            <message></message>
          </data_item>
          <data_item>
            <code></code>
            <message>No code was given</message>
          </data_item>
    </magento_api>");

int counter = 1;
IEnumerable<XNode> nodes =
    from nd in doc.Nodes()
    select nd;
foreach (XNode node in nodes)
{
    Console.WriteLine(counter + "-" + node);
    IEnumerable<XElement> elements =
    from el in node //this is where I've been trying various methods, but no dice.
    select el;
    foreach (XElement e in elements)
    {
           Console.WriteLine(counter + "-" + e.Name + "-" + e.Value + "\r\n");
    }
    counter++;
}

根据上面的XML输入,我希望得到以下输出:

<magento_api>
    <data_item>
        <code>400</code>
        <message>Attribute weight is not applicable for product type Configurable Product</message>
    </data_item>
    <data_item>
        <code>400</code>
        <message>Resource data pre-validation error.</message>
    </data_item>
    <data_item>
        <code>1</code>
    </data_item>
    <data_item>
        <message>No code was given</message>
    </data_item>
</magento_api>

我不确定我是否使用正确的方法迭代节点和元素.

Answer 1

单个单行可以完成工作,无需迭代所有元素.在这里:

doc.Descendants().Where(e => string.IsNullOrEmpty(e.Value)).Remove();

测试仪

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

namespace ConsoleApplication1
{
    public class TestRemove
    {
        public static void Main() {
            Console.WriteLine("----OLD TREE STARTS---");
            XElement doc = XElement.Parse(@"<magento_api>
                                              <data_item>
                                                <code>400</code>
                                                <message>Attribute weight is not applicable for product type Configurable Product</message>
                                              </data_item>
                                              <data_item>
                                                <code>400</code>
                                                <message>Resource data pre-validation error.</message>
                                              </data_item>
                                              <data_item>
                                                <code>1</code>
                                                <message></message>
                                              </data_item>
                                              <data_item>
                                                <code></code>
                                                <message>No code was given</message>
                                              </data_item>
                                        </magento_api>");
            Console.Write(doc.ToString());
            Console.WriteLine("");
            Console.WriteLine("----OLD TREE ENDS---");
            Console.WriteLine("");
            doc.Descendants().Where(e => string.IsNullOrEmpty(e.Value)).Remove();
            Console.WriteLine("----NEW TREE STARTS---");
            Console.Write(doc.ToString());
            Console.WriteLine("");
            Console.WriteLine("----NEW TREE ENDS---");
            Console.ReadKey();
        }
    }
}

它也可以在这里测试

Answer 2

doc.Descendants().Where(e => string.IsNullOrEmpty(e.Value)).Remove(); 

这一行不会抛出充满空子标签的空父标签。它只会删除他们的孩子，这可能适合您的情况，也可能不合适。这是一个非常简单的更改，您只需首先从最低级别开始删除即可。就像是

foreach(XElement child in doc.Descendants().Reverse())
{
    if(!child.HasElements && string.IsNullOrEmpty(child.Value) && !child.HasAttributes) child.Remove();
}

感谢Nyerguds提供的属性建议。