UnrealEngineUWP/Engine/Source/Programs/Windows/CompileTimeAnalyzer/CompileTimeAnalyzer/TreeGridElementComparer.cs

// Copyright 1998-2019 Epic Games, Inc. All Rights Reserved.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;

namespace Timing_Data_Investigator
{
	public class PropertyComparer<TClassType> : IComparer<TClassType>
    {
        private string sCompareProperty;
        private bool bSortDescending;

        public PropertyComparer(string CompareProperty, bool SortDescending)
        {
            sCompareProperty = CompareProperty;
            bSortDescending = SortDescending;
        }

        public int Compare(TClassType x, TClassType y)
        {
			PropertyInfo ComparePropertyInfo = typeof(TClassType).GetProperties().FirstOrDefault(p => p.Name == sCompareProperty);
            if (ComparePropertyInfo == null)
            {
                throw new InvalidOperationException($"Class '{nameof(TClassType)}' does not contain a property named '{sCompareProperty}'!");
            }

            if (!ComparePropertyInfo.PropertyType.GetInterfaces().Any(i => i.Name.Contains("IComparable")))
            {
                throw new InvalidOperationException($"Property type '{ComparePropertyInfo.PropertyType.Name}' is not an IComparable!");
            }

			IComparable xPropValue = ComparePropertyInfo.GetValue(x) as IComparable;
			IComparable yPropValue = ComparePropertyInfo.GetValue(y) as IComparable;
            if (bSortDescending)
            {
                return yPropValue.CompareTo(xPropValue);
            }

            return xPropValue.CompareTo(yPropValue);
        }
    }
}