Remove duplicates of XNodes

Question

I'd like to merge XML files, but without duplicates of the same XNodes. At this point if I have two identical XML files - with the same Privilege nodes - then my merge will have duplicates like this:

Input 1:

<SecurityPrivileges>
   <SecurityPrivilege Principal="Jack Smith">
      <Privilege Type="FileSystem" AccessType="read">c:\log</Privilege>
      <Privilege Type="FileSystem" AccessType="write">c:\log</Privilege>
   </SecurityPrivilege>
</SecurityPrivileges>

Input 2:

<SecurityPrivileges>
   <SecurityPrivilege Principal="Jack Smith">
      <Privilege Type="FileSystem" AccessType="write">c:\log</Privilege>
   </SecurityPrivilege>
</SecurityPrivileges>

Expected output:

<SecurityPrivileges>
   <SecurityPrivilege Principal="Jack Smith">
      <Privilege Type="FileSystem" AccessType="read">c:\log</Privilege>
      <Privilege Type="FileSystem" AccessType="write">c:\log</Privilege>
   </SecurityPrivilege>
</SecurityPrivileges>

Current output:

<SecurityPrivileges>
   <SecurityPrivilege Principal="Jack Smith">
      <Privilege Type="FileSystem" AccessType="read">c:\log</Privilege>
      <Privilege Type="FileSystem" AccessType="write">c:\log</Privilege>
      <Privilege Type="FileSystem" AccessType="write">c:\log</Privilege>
   </SecurityPrivilege>
</SecurityPrivileges>

I try to use the Distinct to remove duplicates, but I can't get it right. I should check the attributes and the innertext of the XNodes. This is where I'm now:

XElement mergeSecurityPrivilege = new XElement(SECURITY_PRIVILEGES, result.Descendants(SECURITY_PRIVILEGE)
 .GroupBy(x => x.Attribute(PRINCIPAL)?.Value)
  .Select(x => new XElement(SECURITY_PRIVILEGE, new XAttribute(x.First().Attribute(PRINCIPAL)), x.Elements())).Distinct());

Could you provide a [mcve]? I'd probably use MoreLINQ and its `DistinctBy` with an anonymous type, but it's hard to give a complete example of that without a complete example of the original code. — Jon Skeet, Apr 03 '18 at 09:20

score 0 · Answer 1 · answered Apr 03 '18 at 08:58

I create a custom class implementing Equals to do the comparison :

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml;
using System.Xml.Linq;

namespace ConsoleApplication1
{
    class Program
    {

        static void Main(string[] args)
        {
            string xml1 = 
             "<SecurityPrivileges>" +
               "<SecurityPrivilege Principal=\"Jack Smith\">" +
                  "<Privilege Type=\"FileSystem\" AccessType=\"read\">c:\\log</Privilege>" +
                  "<Privilege Type=\"FileSystem\" AccessType=\"write\">c:\\log</Privilege>" +
               "</SecurityPrivilege>" +
            "</SecurityPrivileges>";

            string xml2 =
             "<SecurityPrivileges>" +
               "<SecurityPrivilege Principal=\"Jack Smith\">" +
                  "<Privilege Type=\"FileSystem\" AccessType=\"write\">c:\\log</Privilege>" +
               "</SecurityPrivilege>" +
            "</SecurityPrivileges>";

            XDocument doc1 = XDocument.Parse(xml1);
            XElement securityPrivilege1 = doc1.Descendants("SecurityPrivilege").FirstOrDefault();
            XDocument doc2 = XDocument.Parse(xml2);
            XElement securityPrivilege2 = doc2.Descendants("SecurityPrivilege").FirstOrDefault();

            List<XElement> children = securityPrivilege1.Elements().ToList();
            children.AddRange(securityPrivilege2.Elements().ToList());

            var childs = children.Select(x => new { element = x, attributes = x.Attributes().Select(y => new KeyValuePair<string, string>(y.Name.LocalName, (string)y)).OrderBy(z => z.Key).ToList() }).ToList();

            var groups = childs.GroupBy(x => new KeyValuePairCompare() { values = x.attributes }).ToList();

            securityPrivilege1.ReplaceNodes(groups.Select(x => x.FirstOrDefault().element));

        }
    }
    public class KeyValuePairCompare : IEquatable<KeyValuePairCompare>
    {
        public List<KeyValuePair<string, string>> values { get; set; }


        public Boolean Equals(KeyValuePairCompare other)
        {
            Boolean match = (values.Count == other.values.Count) && values.Select((x, i) => new { x = x, i = i }).All(x => (x.x.Key == other.values[x.i].Key) && (x.x.Value == other.values[x.i].Value)); 
            return match;
        }
        public override int GetHashCode()
        {
            return 1;
        }
    }
}

Remove duplicates of XNodes

1 Answers1