EF核心多对多获取查询 、 get; set; } public Category Category { get; set;}我正在使用IQueryable<Profile> query = _context.Profiles.Include(p => p.Categories).Include(p => p.Platforms); if 浏览1提问于2016-12-02得票数4 回答已采纳 ...
EF Core是Entity Framework Core的简称,是一个用于.NET平台的对象关系映射(ORM)框架。它提供了一种简单、灵活且高效的方式来访问数据库,并将数据库中的数据映射到.NET对象中。 在EF Core中,可以使用选择操作符(Select)来指定要从数据库中检索的特定列或属性。而过滤操作符(Where)用于根据特定条件筛选数据。...
if (String.IsNullOrEmpty(path)) throw new ArgumentNullException("path can not empty"); // var query = queryable as ObjectQuery<TEntity>;//ObjectContext時用 var query = queryable as DbQuery<TEntity>;//DbContext時用 if (query != null)//if is a EF ObjectQuery object return query.Include(...
var res = db.HT_REZ.AsQueryable(); if (condition) { res = res.Include(r => r.CF) .Include(r => r.HT_ROOM) .Include(r => r.HT_GRUPS); } res = await res.FirstOrDefaultAsync(r => r.ID == id); but got: Cannot implicitly convert type 'Rez.Models.HT_REZ' to 'System.L...
If possible, you should always try to put Skip/Take/Distinct as the last operation when using EF Core (at least until we address the current limitations). 在我们这个项目中的确存在将 Skip/Take 放在 Select 之前的 LINQ 查询代码,修改之后问题立马解决。而发生全表查询的数据库表所对应的实体,是在 ...
Besides, you can check the related EF core package, make sure you are using the correct package, in Asp.net core application, you should use Microsoft.EntityFrameworkCore. More detail information, see Tutorial: Get started with EF Core in an ASP.NET MVC web app. Finally, if still not ...
您可以使用自己的扩展方法来执行此操作，该方法显式调用适当的扩展方法：
//check if exists using(varctx =newModelContext(options)) { //exception here boolisExists = ctx.Model1.Include(m1 => m1.Model2).Contains(myModel1); Console.WriteLine(isExists); } } finally { connection.Close(); } Console.ReadKey(); ...
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最初接触EF延时加载时，以为只存在这种性能低下的⽅案，在了解include⽅法后，才知道这种神奇的⽅案，它与linq to sql中的DataLoadOptions⽐较类似，译为⽴即加载关联对象。在这⾥，我对include说⼀声，对不起，是我冤枉你了，呵呵。实验代码如下：Infrastructure层： public IQueryable<WebManageUsers>...