委托关键字与 lambda 表示法

问题描述

一经编译，有没有区别:

Once it is compiled, is there a difference between:

delegate { x = 0; }

和

() => { x = 0 }

?

推荐答案

简答:没有.

可能不相关的较长答案:

Longer answer that may not be relevant:

• 如果将 lambda 分配给委托类型(例如 Func 或 Action)，您将获得匿名委托.
• 如果将 lambda 分配给 Expression 类型，您将获得表达式树而不是匿名委托.然后可以将表达式树编译为匿名委托.

• If you assign the lambda to a delegate type (such as Func or Action) you'll get an anonymous delegate.
• If you assign the lambda to an Expression type, you'll get an expression tree instead of a anonymous delegate. The expression tree can then be compiled to an anonymous delegate.

这是表达式的一些链接.

Here's some links for Expressions.

• System.Linq.Expression.Expression(TDelegate)(开始在这里).
• Linq in-memory with delegates(例如 System.Func)使用 System.Linq.Enumerable.带有表达式的 Linq to SQL(和其他任何东西)使用 System.Linq.可查询.查看这些方法的参数.
• 一个解释来自 ScottGu.简而言之，Linq in-memory 会产生一些匿名方法来解决您的查询.Linq to SQL 将生成一个表示查询的表达式树，然后将该树转换为 T-SQL.Linq to Entities 将生成一个表示查询的表达式树，然后将该树转换为适合平台的 SQL.

• System.Linq.Expression.Expression(TDelegate) (start here).
• Linq in-memory with delegates (such as System.Func) uses System.Linq.Enumerable. Linq to SQL (and anything else) with expressions uses System.Linq.Queryable. Check out the parameters on those methods.
• An Explanation from ScottGu. In a nutshell, Linq in-memory will produce some anonymous methods to resolve your query. Linq to SQL will produce an expression tree that represents the query and then translate that tree into T-SQL. Linq to Entities will produce an expression tree that represents the query and then translate that tree into platform appropriate SQL.

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