如何从字符串更新/替换XElement的元素？ [英] How can I update/replace an element of an XElement from a string?

问题描述

所以这里是我的情况。

我有一个XElement，我们称它为root，它有后代，它有后代等。我使用LINQ XML，使用 .ToString（）将其加载到备忘录编辑器中，并进行编辑。现在我想用已编辑的版本更新/替换原始的后代元素。

I have an XElement, let's call it root, which has descendents, which have descendents, etc. I pull a descendent using LINQ to XML, load it into a memo editor using .ToString() and edit it. Now I want to update/replace the original descendent element with the edited version.

让我提到这是一个简单的XML文件，没有模式，不使用DOM，我只需要能够编辑和更新/替换一个元素。

Let me mention that this is a simple XML file, with no schema, not using DOM, etc. I only need to be able to edit and update/replace an element.

这里是我的XML模型：

Here's a mockup of my XML:

<Root>
  <Genre Name="Rock">
    <Artist Name="Pink Floyd">
      <BandMembers>
        <Member>Nick Mason</Member>
        <Member>Syd Barret</Member>
        <Member>David Gilmour</Member>
        <Member>Roger Water</Member>
        <Member>Richard Wright</Member>
      </BandMembers>
      <Category>Favorite band of all time</Category>
    </Artist>
    <Artist Name="Led Zepelin">
      <Category>Love the band</Category>
    </Artist>
  </Genre>
  <Genre Name="Blues">
    <Artist Name="Muddy Waters">
      <Instrument>Harmonica</Instrument>
    </Artist>
    <Artist Name="Howling Wolf">
      <Instrument>Guitar</Instrument>
    </Artist>
  </Genre>
</Root>

现在我想编辑Pink Floyd元素来纠正Roger Waters的姓氏。我得到那个元素，将其转换为字符串，将其加载到我的编辑器中，进行所需的更改，然后使用 .Parse（）将其转换回XElement。

Now say I want to edit "Pink Floyd" element to correct Roger Waters' last name. I get that element, convert it to a string, load it into my editor, make the changes that I want, and convert it back to an XElement using .Parse().

现在，如何更新/替换原始XML中的Pink Floyd节点？

Now, how can I update/replace the "Pink Floyd" node in my original XML?

推荐答案

您可以使用 XElement.ReplaceWith 方法：

You could use the XElement.ReplaceWith method:

// input would be your edited XML, this is just sample data to illustrate
string input = @"<Artist Name=""Pink Floyd"">
  <BandMembers>
    <Member>Nick Mason</Member>
    <Member>Syd Barret</Member>
    <Member>David Gilmour</Member>
    <Member>Roger Waters</Member>
    <Member>Richard Wright</Member>
  </BandMembers>
  <Category>Favorite band of all time</Category>
</Artist>";

var replacement = XElement.Parse(input);
var pinkFloyd = xml.Elements("Genre")
                   .Where(e => e.Attribute("Name").Value == "Rock")
                   .Elements("Artist")
                   .Single(e => e.Attribute("Name").Value == "Pink Floyd");

pinkFloyd.ReplaceWith(replacement);
Console.WriteLine(xml);

您应该添加一些错误检查。我使用 Single ，因为我确定节点存在，但如果有机会，不是你应该使用 SingleOrDefault 并在使用结果之前检查 null 。

You should add some error checking though. I used Single since I'm sure the node exists, but if there's a chance it isn't you should use SingleOrDefault and check for null before using the result.

此外，如果输入无效，将上述代码包装在try / catch中并处理可能抛出的任何 XmlException 。

Also, if the input is invalid you'll need to wrap the above code in a try/catch and handle any XmlException that might be thrown.

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