public static Func <T, T, int> BuildComparerFunc(SortCriteria sortCriteria)
{
string sortField = sortCriteria.SortField;
if (!SortComparerFactory <T> .s_ComparerCache.TryGetValue(sortField, out Func <T, T, int> comparerFunc))
{
comparerFunc = (x, y) =>
{
object?valueX = SortComparerReflectionHelper.FindPropertyGetMethod(x !.GetType(), sortField)?.Invoke(x, null);
object?valueY = SortComparerReflectionHelper.FindPropertyGetMethod(y !.GetType(), sortField)?.Invoke(y, null);
if (!TryEnsureValidReferences(valueX, valueY, out int referenceComparisonResult))
{
return(referenceComparisonResult);
}
Type targetType = SortComparerReflectionHelper.ResolveTargetType(valueX.GetType());
if (targetType == SortComparerReflectionHelper.ResolveTargetType(valueY.GetType()))
{
MethodInfo?compareToMethodInfo = SortComparerReflectionHelper.FindCompareToMethodInfo(targetType);
if (compareToMethodInfo != null)
{
return((int)compareToMethodInfo.Invoke(valueX, new object[] { valueY }));
}
}
return(Comparer <object> .Default.Compare(valueX, valueY));
};
SortComparerFactory <T> .s_ComparerCache.TryAdd(sortField, comparerFunc);
}
return(comparerFunc);
}
internal static Func <T, T, int> BuildPropertyComparer(Type typeX, Type typeY, string sortField)
{
MethodInfo?propertyX = SortComparerReflectionHelper.FindPropertyGetMethod(typeX, sortField);
MethodInfo?propertyY = SortComparerReflectionHelper.FindPropertyGetMethod(typeY, sortField);
if (propertyX == null && propertyY == null)
{
return((x, y) => 0);
}
if (propertyX == null || propertyY == null)
{
return(BuildOneSidedComparer((propertyX ?? propertyY) !, propertyX != null, sortField));
}
Type targetType = SortComparerReflectionHelper.ResolveTargetType(propertyX.ReturnType);
if (targetType != SortComparerReflectionHelper.ResolveTargetType(propertyY.ReturnType))
{
return(BuildDefaultComparer(propertyX, propertyY, sortField));
}
bool isEnum = targetType.IsEnum;
if (isEnum)
{
targetType = typeof(long);
}
MethodInfo?compareToMethodInfo = SortComparerReflectionHelper.FindCompareToMethodInfo(targetType);
return(compareToMethodInfo == null
? BuildDefaultComparer(propertyX, propertyY, sortField)
: !targetType.IsValueType
? BuildReferenceTypePropertyComparer(propertyX, propertyY, sortField, targetType, compareToMethodInfo)
: BuildValueTypePropertyComparer(propertyX, propertyY, sortField, typeof(Nullable <>).MakeGenericType(targetType), targetType, compareToMethodInfo, isEnum));
}
