来自XML文件错误对象引用的C＃读取元素未设置 [英] C# reading element from XML file error object reference not set

问题描述

我用C＃编写了一个程序来读取XML文件中的设置

I wrote a program in C# to read settings from an XML file

<?xml version="1.0" encoding="UTF-8"?>
-<settings><setting2>4</setting2><setting3> </setting3><setting4> </setting4><setting5> </setting5><setting6> </setting6><setting7> </setting7><setting8> </setting8><setting9> </setting9><setting10> </setting10><setting11> </setting11><setting12> </setting12><setting13> </setting13><setting14> </setting14><setting15> </setting15><setting16> </setting16><setting17> </setting17></settings>

现在我想在程序中加载它

Now i want to load it in program with

string xmlfilename = Path.Combine(Application.StartupPath, filename);
XDocument doc = new XDocument();
 XDocument.Load(xmlfilename);
textBox1.Text + doc.Root.Element("settings").Element("setting2").Value;

但是它将错误对象引用设置为未设置为对象的实例。

But it gives error object reference not set to an instance of an object.

推荐答案

从您的代码中，xml文件未加载到 doc 对象，其次由于根元素而导致错误。请尝试使用以下代码：

From your code, xml file was not loading to doc object and secondly you are getting error due to root element. Please try with below code:

Document doc = XDocument.Load(xmlfilename);
// This is one way to fetch XML data
string temp = textBox1.Text + doc.Root.Element("setting2").Value;
// or
// Another way to fetch XML data
string temp = textBox1.Text + doc.Element("settings").Element("setting2").Value;

1。尝试使用XmlDocument



2.一次一步（XmlElement root = doc.Root; root.Element（settings）等）直到得到返回null



3.而不是去.Element.Element.Element将XPath写入想要的元素（// settings / setting2）



其中一些应该解决问题，玩一下代码。



这是完整的例子：通过XMLDocument和XDocument解析XML文档 [ ^ ]

1. Try with XmlDocument

2. Go one step at a time (XmlElement root = doc.Root; root.Element(settings) etc.) until you get which returns null

3. Instead of going .Element.Element.Element write XPath to wanted element (//settings/setting2)

Some of this should resolve the problem, play a bit with the code.

Here is complete example: Parse XML Documents by XMLDocument and XDocument[^]

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