C# – delegate keyword vs. lambda notation

.netanonymous-methodsc++delegateslambda

Once it is compiled, is there a difference between:

delegate { x = 0; }

and

() => { x = 0 }

?

Best Solution

Short answer : no.

Longer answer that may not be relevant:

  • 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.

Edit: Here's some links for Expressions.

  • 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.