LINQ to XML后代和元素之间有什么区别？

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最佳答案

Elements finds only those elements that are direct descendents, i.e. immediate children.

Descendants finds children at any level, i.e. children, grand-children, etc...

Here is an example demonstrating the difference:

<?xml version="1.0" encoding="utf-8" ?>
<foo>
<bar>Test 1</bar>
<baz>
<bar>Test 2</bar>
</baz>
<bar>Test 3</bar>
</foo>

Code:

XDocument doc = XDocument.Load("input.xml");
XElement root = doc.Root;


foreach (XElement e in root.Elements("bar"))
{
Console.WriteLine("Elements : " + e.Value);
}


foreach (XElement e in root.Descendants("bar"))
{
Console.WriteLine("Descendants : " + e.Value);
}

Result:

Elements : Test 1
Elements : Test 3
Descendants : Test 1
Descendants : Test 2
Descendants : Test 3

If you know that the elements you want are immediate children then you will get better performance if you use Elements instead of Descendants.