Extensions.cs

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

namespace Schneegans.Unattend;

public static class Extensions
{
  public static XmlNode SelectSingleNodeOrThrow(this XmlNode node, string xpath, XmlNamespaceManager nsmgr)
  {
    return node.SelectSingleNode(xpath, nsmgr) ?? throw new NullReferenceException($"No node matches XPath '{xpath}'.");
  }

  public static XmlNode SelectSingleNodeOrThrow(this XmlNode node, string xpath)
  {
    return node.SelectSingleNode(xpath) ?? throw new NullReferenceException($"No node matches XPath '{xpath}'.");
  }

  public static IEnumerable<XmlNode> SelectNodesOrEmpty(this XmlNode node, string xpath)
  {
    XmlNodeList? result = node.SelectNodes(xpath);
    return result == null ? [] : result.Cast<XmlNode>();
  }

  public static IEnumerable<XmlNode> SelectNodesOrEmpty(this XmlNode node, string xpath, XmlNamespaceManager nsmgr)
  {
    XmlNodeList? result = node.SelectNodes(xpath, nsmgr);
    return result == null ? [] : result.Cast<XmlNode>();
  }

  public static void RemoveSelf(this XmlNode node)
  {
    node.ParentNode!.RemoveChild(node);
  }

  public static IImmutableDictionary<string, T> ToKeyedDictionary<T>(this IEnumerable<T>? enumerable) where T : IKeyed
  {
    if (enumerable == null)
    {
      throw new NullReferenceException();
    }
    return enumerable.ToImmutableDictionary(
      keySelector: value => value.Id,
      keyComparer: StringComparer.OrdinalIgnoreCase
    );
  }

  public static string JoinString<T>(this IEnumerable<T> enumerable, string separator)
  {
    return string.Join(separator, enumerable);
  }

  public static string JoinString<T>(this IEnumerable<T> enumerable, char separator)
  {
    return string.Join(separator, enumerable);
  }
}