Question

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> 

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.

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

Answer 1

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'] 

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

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.

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

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 } 

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.

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