Linq To SQL:按任意属性(列)名称对查询进行排序 [英] Linq To SQL: Sort Query by Arbitrary Property(Column) Name

问题描述

我有一个更大/更复杂的问题，但为简单起见，让我们考虑以下问题:

I have a larger/more complex problem, but for simplicity sake, let us consider the following:

让我们说我在 SQL数据库中有一个名为 Product 的表，该表有两列 ID (int，主要键)和名称((varchar/字符串)).我还有一个简单的 LINQ DataContext .

Let us say that I have table in the SQL DataBase called Product, having two columns, ID (int, primary key) and Name (varchar/string). I also have a simple LINQ DataContext.

我构造了一个查询并将其交给我的"函数.让我们说这就像:(尽管可能会更复杂)

I have a query constructed and handed to "my" function. Let us say it is something like: (though it may be a bit more complex)

IQueryable<Product> query = from p in db.Products select p;

一旦我的方法获得此查询并作为参数传递，它就必须更改排序顺序，例如

Once my method gets this query, passed in as a parameter, it has to change the sort order e.g.

IQueryable<Product> sortedQuery = query.OrderBy(x => x.Name);

我想使它更通用，即指定要排序的字段.通常，我可以执行一个包含字符串的switch语句.但是我想知道是否有一种直接传递参数的方法.我打算将此扩展到其他数据库表，因此这些switch语句将变得乏味.

I would like to make this more generic i.e. to specify the field to sort on. Normally, I can do a switch statement that takes a string. However I would like to know if there is a way to pass the parameter directly. I intend to extend this to other Database tables, so these switch statements would get tedious.

我正在尝试类似的事情:

I was trying something like:

IQueryable<Product> sortedQuery = query.OrderBy(x => (typeof(Product)).GetProperty("Name"));

但这不起作用.我还想确保维护LINQ to SQL，即要在SQL Server上进行的排序.因此，如果我进行调试，则应该从此LINQ查询中获取一个SQL查询.

But this does not work. I also want to ensure that the LINQ to SQL is maintained i.e. the sort to be done on the SQL Server. Hence if I debug, I should get a SQL query from this LINQ query.

预先感谢您的帮助.

推荐答案

您可以为此目的使用Dynamic Linq.

请参见然后您可以像这样拨打电话:

Then you can make calls like this:

var query = DBContext.Users.Where( "Age > 3" ).OrderBy( "Name asc" );

这篇关于Linq To SQL:按任意属性(列)名称对查询进行排序的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！