Updated Linq to Sql (markdown)

AlexLEWIS
2021-09-27 14:06:08 +08:00
parent 6c81d4d94f
commit 64d12d8e62

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[中文](LinqToSql) | **English**
原本不支持 IQueryable 主要出于使用习惯的考虑编写代码的智能总会提示出现一堆你不想使用的方法对不起我有强迫症IQueryable 自身提供了一堆没法实现的方法,还有外部入侵的扩展方法,严重影响编码体验。如下图:
Originally not supporting IQueryable is mainly due to the consideration of usage habits. The intelligence of writing code will always prompt a bunch of methods you don't want to use. IQueryable itself provides a bunch of methods that cannot be implemented, as well as external intrusion extension methods, which seriously affect Coding experience. As shown below:
![image](https://user-images.githubusercontent.com/16286519/57295126-5dd7bd00-70fc-11e9-99c0-d1c46423afa2.png)
v1.4.0+ 版本请使用以下命令安装(老版本不需要安装):
For FreeSql v1.4.0+ version, please use the following items to install with commands (old version does not need to be installed):
> dotnet add package FreeSql.Extensions.Linq
## 特别说明
## Special Note
* 请尽量不要在 ISelect 模式下的使用 Linq 方法GroupJoin、Select、SelectMany、Join、DefaultIfEmpty
* Please try not to use the following Linq methods in `ISelect` mode: `GroupJoin`, `Select`, `SelectMany`, `Join` and `DefaultIfEmpty`.
* 如果一定要在 ISelect 中使用 .Select() 方法,请务必在 .ToList() 之前调用它;
* If you must use the `.Select()` method in `ISelect`, be sure to call it before `.ToList()`.
## IQueryable
FreeSql 提供强大的数据查询对象 ISelect
FreeSql provides a powerful data query object: ISelect.
FreeSql.Extensions.Linq v1.4.0+ 实现了 IQueryable 查询对象常用功能,以便在各框架中交互使用。
FreeSql.Extensions.Linq v1.4.0+ implements the common functions of IQueryable query objects for interactive use in various frameworks.
```csharp
// ISelect 转为 IQueryable
//Convert ISelect to IQueryable
IQueryable<Student> queryable = fsql.Select<Student>().AsQueryable();
//Linq 方法查询
//Linq Query
var t1 = queryable.Where(a => a.id == 1).FirstOrDefault();
// IQueryable 还原为 ISelect
//Restore IQueryable to ISelect
ISelect<Studeng> select = queryable.RestoreToSelect();
```
注意IQueryable 的实现目前不支持 GroupBy可以考虑使用 RestoreSelect 方法转回 ISelect 进行查询
Note: The implementation of IQueryable does not currently support `GroupBy`. You can consider using the `RestoreSelect` method to switch back to `ISelect` for query.
## Where
```csharp