在实体框架中进行复杂的选择

Question

请帮我做出这个选择：

"SELECT t.id, t.Status, t.CardMachine, t.ValueNow, (6371 * acos( cos( radians(" + 
ent.Latitude.ToString().Replace(',', '.') +
") ) * cos( radians( t.LatitudeNow ) ) * cos( radians( t.LongitudeNow ) - " +
" radians(" + ent.Longitude.ToString().Replace(',', '.') + 
") ) + sin( radians(" + 
ent.Latitude.ToString().Replace(',', '.') +
") ) * sin( radians( t.LatitudeNow ) ) ) ) AS distance 
FROM dbo.Delivers t) TMP " + 
" INNER JOIN dbo.Vehicles v ON v.DeliverId = TMP.id " + 
" WHERE distance < 25 AND TMP.Status = 1  AND CardMachine = 1 
AND v.BoxWidth >= " + 
 ent.MostWidthProduct.ToString().Replace(',', '.') + 
" AND v.BoxLength >= " + 
ent.MostLengthProduct.ToString().Replace(',', '.') +  
" AND v.Status = 1 
ORDER BY valueNow, distance"

使用实体框架。

Answer 1

这是一个相当复杂的查询，但是我已经尽力给你一个答案，我很确定可能有更好或更简洁的方法来编写它，或者使用 linq 表达式：

var latitude = ent.Latitude.ToString().Replace(',', '.');
            var longitude = ent.Longitude.ToString().Replace(',', '.');
            var mostWidthProduct = ent.MostWidthProduct.ToString().Replace(',', '.');
            var mostLengthProduct = ent.MostLengthProduct.ToString().Replace(',', '.');

            using (var db = new db())
            {
                var delivers = db.DeliverSet.Include(a => a.Vehicle).
                    Where(o => WherePredicate(o, latitude, longitude, mostWidthProduct, mostLengthProduct)).
                    OrderBy(o => o.ValueNow).ThenBy(o => OrderPredicate(o,latitude,longitude));

                //Do whatever you want with delivers
            }

使用的方法：

private static double OrderPredicate(Deliver o,double latitude, double longitude)
        {
            return GetDistance(o, latitude, longitude);
        }


        private static bool WherePredicate(Deliver o, double latitude, double longitude, double mostWidthProduct, double mostLengthProduct)
        {
            var distance = GetDistance(o, latitude, longitude);

            return
                distance > 25 &&
                o.Status == 1 &&
                o.CardMachine == 1 &&
                o.Vehicle.BoxWidth >= mostWidthProduct &&
                o.Vehicle.BoxLength >= mostLengthProduct &&
                o.Vehicle.Status == 1;
        }

        private static double GetDistance(Deliver o, double latitude, double longitude)
        {
            var distance = 6371*Math.Acos(Math.Cos(ConvertToRadians(latitude))*
                                          Math.Cos(ConvertToRadians(o.LatitudeNow))*
                                          Math.Cos(ConvertToRadians(o.LongitudeNow) - ConvertToRadians(longitude)) +
                                          Math.Sin(ConvertToRadians(latitude)*
                                                   Math.Sin(ConvertToRadians(o.LatitudeNow))));
            return distance;
        }


        public static double ConvertToRadians(double angle)
        {
            return (Math.PI / 180) * angle;
        }