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  1. using System;
  2. using System.Collections.Generic;
  3. using System.Linq;
  4.  
  5. public class Test
  6. {
  7.     public static void Main()
  8.     {
  9.         var foos = Enumerable.Range(1, 1000).Select(_ => new Foo()).ToList();
  10.  
  11.         new Test().GroupChanges(foos);
  12.     }
  13.  
  14.     public void GroupChanges<TResult>(List<TResult> changes)
  15.     {
  16.         const string KeyPropertyName = "TransactionSequence";
  17.  
  18.         var changeSet = changes
  19.             .GroupBy(change => /*change.TransactionSequence */ 
  20.                 (byte[])change.GetType().GetProperty(KeyPropertyName).GetValue(change)
  21.                 , new ArrayComparer<byte>())
  22.             .ToList();
  23.  
  24.         Console.WriteLine(changeSet.Count);
  25.     }
  26. }
  27.  
  28. public class Foo
  29. {
  30.     private static readonly byte[][] Keys = new[] {
  31.             Guid.NewGuid().ToByteArray(),
  32.             Guid.NewGuid().ToByteArray(),
  33.             Guid.NewGuid().ToByteArray()
  34.         };
  35.  
  36.     private static readonly Random rand = new Random();
  37.  
  38.     public Foo()
  39.     {
  40.         this.TransactionSequence = Keys[rand.Next(3)];
  41.     }
  42.  
  43.     public byte[] TransactionSequence { get; private set; }
  44. }
  45.  
  46. public class ArrayComparer<T> : IEqualityComparer<T[]>
  47. {
  48.     public bool Equals(T[] x, T[] y)
  49.     {
  50.         return x.SequenceEqual(y);
  51.     }
  52.  
  53.     public int GetHashCode(T[] obj)
  54.     {
  55.         return obj.GetHashCode();
  56.     }
  57. }
Success #stdin #stdout 0.02s 132800KB
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stdout 
3
https://ideone.com/YWAz7Y
language:
C# (gmcs 5.20.1)
created:
8 years ago
visibility:
public

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