C# - LINQ - 通过GPS纬度和经度的最短距离 [英] C# - LINQ - shortest distance by GPS latitude and longitude
问题描述
我认为应该是这样(我在这里找到很多示例代码,像这样):
var coord = new GeoCoordinate(纬度,经度);
var nearest =(from h in db.hotels
let geo = new GeoCoordinate(h.gps.lat,h.gps.lng)
orderby geo.GetDistanceTo(coord)
选择h)。
问题是我尝试搜索某些东西时出现此错误:
只有无参数的构造函数和初始值设置在LINQ
中支持实体
我试图google,我发现将linq分成两个可以帮助我,但我不知道如何。感谢您的帮助。
您可以使用对象初始化器而不是参数化构造函数:
var nearest =(from h in db.hotels
let geo = new GeoCoordinate {Latitude = h.gps.lat,Longitude = h.gps.lng}
orderby geo.GetDistanceTo(coord)
select h).Take(10);
但是您可能会遇到由GetDistanceTo方法引起的问题,您可以提供该方法的实现吗?
I have database and in it I have class hotel with gps coordinates. I want to get closest places to coordinates which I choose.
I think It should look like this (I found many example codes here and like this one):
var coord = new GeoCoordinate(latitude, longitude);
var nearest = (from h in db.hotels
let geo = new GeoCoordinate(h.gps.lat, h.gps.lng)
orderby geo.GetDistanceTo(coord)
select h).Take(10);
The problem is that I have this error when I tried to search for something:
Only parameterless constructors and initializers are supported in LINQ to Entities
I tried to google it and I found that dividing that linq into two can help me but I am not sure how. Thanks for help.
You can use the object initializer instead of parameterized constructor:
var nearest = (from h in db.hotels
let geo = new GeoCoordinate{ Latitude = h.gps.lat, Longitude = h.gps.lng}
orderby geo.GetDistanceTo(coord)
select h).Take(10);
But you will likely have problems caused by the GetDistanceTo method, could you provide the implementation of that method?
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