// ***********************************************************************
// Assembly : FCS.Lib.Utility
// Author : fhdk
// Created : 2022 12 17 13:33
//
// Last Modified By: fhdk
// Last Modified On : 2023 03 14 09:16
// ***********************************************************************
//
// Copyright (C) 2022-2023 FCS Frede's Computer Services.
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as
// published by the Free Software Foundation, either version 3 of the
// License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see [https://www.gnu.org/licenses]
//
//
// ***********************************************************************
using System;
using System.Linq;
using System.Linq.Expressions;
using System.Reflection;
namespace FCS.Lib.Utility;
///
/// Class QueryHelper.
///
public static class QueryHelper
{
// https://stackoverflow.com/a/45761590
///
/// OrderBy
///
///
///
///
///
///
public static IQueryable OrderBy(this IQueryable q, string name, bool desc)
{
var entityType = typeof(TModel);
var p = entityType.GetProperty(name);
var m = typeof(QueryHelper)
.GetMethod("OrderByProperty")
?.MakeGenericMethod(entityType, p.PropertyType);
return (IQueryable)m.Invoke(null, new object[] { q, p, desc });
}
///
/// ThenBy
///
///
///
///
///
///
public static IQueryable ThenBy(this IQueryable q, string name, bool desc)
{
var entityType = typeof(TModel);
var p = entityType.GetProperty(name);
var m = typeof(QueryHelper)
.GetMethod("OrderByProperty")
?.MakeGenericMethod(entityType, p.PropertyType);
return (IQueryable)m.Invoke(null, new object[] { q, p, desc });
}
///
/// OrderByProperty
///
///
///
///
///
///
///
public static IQueryable OrderByProperty(IQueryable q, PropertyInfo p, bool desc)
{
var pe = Expression.Parameter(typeof(TModel));
Expression se = Expression.Convert(Expression.Property(pe, p), typeof(object));
var exp = Expression.Lambda>(se, pe);
return desc ? q.OrderByDescending(exp) : q.OrderBy(exp);
}
}