C# 获取 xelement 属性值
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get xelement attribute value
提问by LFurness
I have an XElement that looks like this:
我有一个看起来像这样的 XElement：
<User ID="11" Name="Juan Diaz" LoginName="DN1\jdiaz" xmlns="http://schemas.microsoft.com/sharepoint/soap/directory/" />
How can I use XML to extract the value of the LoginName attribute? I tried the following, but the q2 "Enumeration yielded no results".
如何使用 XML 提取 LoginName 属性的值？我尝试了以下操作，但 q2“枚举没有结果”。
var q2 = from node in el.Descendants("User")
let loginName = node.Attribute(ns + "LoginName")
select new { LoginName = (loginName != null) };
foreach (var node in q2)
{
Console.WriteLine("LoginName={0}", node.LoginName);
}
采纳答案by Sergey Berezovskiy
var xml = @"<User ID=""11""
Name=""Juan Diaz""
LoginName=""DN1\jdiaz""
xmlns=""http://schemas.microsoft.com/sharepoint/soap/directory/"" />";
var user = XElement.Parse(xml);
var login = user.Attribute("LoginName").Value; // "DN1\jdiaz"
回答by LFurness
I ended up using string manipulation to get the value, so I'll post that code, but I would still like to see an XML approach if there is one.
我最终使用字符串操作来获取值，因此我将发布该代码，但我仍然希望看到一种 XML 方法（如果有的话）。
string strEl = el.ToString();
string[] words = strEl.Split(' ');
foreach (string word in words)
{
if (word.StartsWith("LoginName"))
{
strEl = word;
int first = strEl.IndexOf("\"");
int last = strEl.LastIndexOf("\"");
string str2 = strEl.Substring(first + 1, last - first - 1);
//str2 = "dn1\jdiaz"
}
}
回答by sora0419
XmlDocument doc = new XmlDocument();
doc.Load("myFile.xml"); //load your xml file
XmlNode user = doc.getElementByTagName("User"); //find node by tag name
string login = user.Attributes["LoginName"] != null ? user.Attributes["LoginName"].Value : "unknown login";
The last line of code, where it's setting the string login, the format looks like this...
最后一行代码，在那里设置string login，格式看起来像这样......
var variable = condition ? A : B;
It's basically saying that if condition is true, variable equals A, otherwise variable equals B.
基本上是说如果条件是true，变量等于 A，否则变量等于 B。
回答by adgteq
from the docs for XAttribute.Value:
来自 XAttribute.Value 的文档：
If you are getting the value and the attribute might not exist, it is more convenient to use the explicit conversion operators, and assign the attribute to a nullable type such as
stringorNullable<T>ofInt32. If the attribute does not exist, then the nullable type is set to null.
如果您正在获取值并且该属性可能不存在，则使用显式转换运算符并将该属性分配给可空类型（例如
stringorNullable<T>of ）会更方便Int32。如果该属性不存在，则可空类型设置为空。
