在XML中查找多个属性 [英] Find through multiple attributes in XML

问题描述

我正在尝试搜索XML中的多个属性:

I'm trying to search multiple attributes in XML :

<APIS>
  <API Key="00001">
    <field Username="username1" UserPassword="password1" FileName="Filename1.xml"/>
    <field Username="username2" UserPassword="password2" FileName="Filename2.xml"/>
    <field Username="username3" UserPassword="password3" FileName="Filename3.xml"/>
  </API>
</APIS>

我需要检查字段"中的用户名和UserPassword值是否都是我要与数据集值进行比较的值，有没有一种方法可以检查多个属性(AND条件)而无需编写自己的使用逻辑标志和中断循环.

I need to check if in the "field" the Username AND UserPassword values are both what I am comparing with my Dataset values, is there a way where I can check multiple attributes (AND condition) without writing my own logic of using Flags and breaking out of loops.

有XMLDoc的内置函数吗?任何帮助，将不胜感激！

Is there a built in function of XMLDoc that does it? Any help would be appreciated!

推荐答案

要在提供的XML代码段中搜索所需内容，您需要以下XPath表达式:

To search for what you want in the snippet of XML you provided, you would need the following XPath expression:

/APIS/API/field[@Username='username1' and @UserPassword='password1']

如果用户名和密码匹配，这将返回某些内容，否则将返回

This would either return something, if user name and password match - or not if they don't.

当然，XPath表达式只是一个字符串-例如，您可以使用在表单字段中输入的值来动态构建它.

Of couse the XPath expression is just a string - you can build it dynamically with values that were entered into a form field, for example.

如果您告诉您所使用的语言/环境，此处发布的代码示例可能会变得更加具体.

If you tell what language/environment you are in, code samples posted here will likely get more specific.

这是在C#中执行此操作的一种方法(VB.NET是类似的):

This is a way to do it in C# (VB.NET is analogous):

// make sure the following line is included in your class
using System.Xml;

XmlDocument xmldoc = new XmlDocument();
xmldoc.Load("your XML string or file");

string xpath = "/APIS/API/field[@Username='{0}' and @UserPassword='{1}']";
string username = "username1";
string password = "password1";

xpath = String.Format(xpath, username, password);
XmlNode userNode = xmldoc.SelectSingleNode(xpath);

if (userNode != null)
{
  // found something with given user name and password
}
else
{
  // username or password incorrect
}

请注意，用户名和密码都不能包含单引号，否则以上示例将失败.这是有关此特殊性的一些信息.

Be aware that neither user names nor passwords can contain single quotes, or the above example will fail. Here is some info on this peculiarity.

还有Microsoft提供的操作方法:如何:使用System.Xml.XmlDocument类在Visual C#.NET中执行XPath查询

There is also a How-To from Microsoft available: HOW TO: Use the System.Xml.XmlDocument Class to Execute XPath Queries in Visual C# .NET

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