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  1. using System;
  2. using System.Linq;
  3. using System.Linq.Expressions;
  4.  
  5. public class Test
  6. {
  7.  
  8.             public static Func<T,T,bool> MakeComparator<T>() {
  9.             var lhs = Expression.Parameter(typeof (T), "lhs");
  10.             var rhs = Expression.Parameter(typeof (T), "rhs");
  11.             var allPropChecks = typeof(T)
  12.                 .GetProperties()
  13.                 .Where(p => p.CanRead && p.GetIndexParameters().Length == 0)
  14.                 .Select(p => Expression.Equal(Expression.Property(lhs, p), Expression.Property(rhs, p)))
  15.                 .ToList();
  16.             Expression compare;
  17.             if (allPropChecks.Count == 0) {
  18.                 return (a,b) => true; // Objects with no properties are the same
  19.             } else {
  20.                 compare = allPropChecks[0];
  21.                 compare = allPropChecks
  22.                     .Skip(1)
  23.                     .Aggregate(compare, Expression.AndAlso);
  24.             }
  25.             return (Func<T, T, bool>)Expression.Lambda(compare, new[] { lhs, rhs }).Compile();
  26.         }
  27.        class Point3D {
  28.             public int X { get; set; }
  29.             public int Y { get; set; }
  30.             public int Z { get; set; }
  31.         }
  32.         public static void Main() {
  33.             var cmp = MakeComparator<Point3D>();
  34.             var p1 = new Point3D {X = 1, Y = 2, Z = 3};
  35.             var p2 = new Point3D { X = 1, Y = 2, Z = 3 };
  36.             var p3 = new Point3D { X = 1, Y = 3, Z = 1 };
  37.             Console.WriteLine(cmp(p1, p2));
  38.             Console.WriteLine(cmp(p2, p3));
  39.         }
  40. }
Success #stdin #stdout 0.07s 34488KB
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https://ideone.com/8Slhhm
language:
C# (gmcs 5.20.1)
created:
10 years ago
visibility:
public

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