Lambda expression vs anonymous methods

Question

I would like to know what is the difference. Currently I am learning this stuff and it seems to me like these are just the same:

delegate void X();

X instanceOfX;

instanceOfX = delegate() { code };

instanceOfX = () => { code };

Also if the lambda are newer, should I just use lambda and forget on anonymous methods?

Think in terms of evolution of the language. In C# 1, we had delegates. In C# 2, they added anonymous methods. C# 3 added lambdas. Easier ways to accomplish similar tasks. For more on the evolution, I would encourage you to check out the book *C# In Depth*. — Anthony Pegram, Feb 08 '11 at 14:58

score 19 · Accepted Answer · answered Feb 08 '11 at 14:55

19

Yes, lambda expressions are just very special anonymous methods.

However, there are some deep differences. Start with Eric Lippert's Lambda Expression vs. Anonymous Methods, Part One and continue to the rest of the series.

answered Feb 08 '11 at 14:55

jason

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So what's special about them? – recursive Feb 08 '11 at 14:57
What is special about them thanks – lojol Feb 08 '11 at 14:57
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@recursive for a start, one MAJOR difference is that single line Lambdas can be assigned to an Expression tree whereas Anonymous methods cannot. – Doctor Jones Feb 08 '11 at 15:06
I prefer anonymous method, I'm not always using linq otherwise I like use FindAll from List. – BlaShadow Jul 08 '13 at 17:10

score 4 · Answer 2 · edited Aug 26 '20 at 14:45

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The only difference is the lambda can be easily cast to Expression<Func<void>>. The delegates are purely just methods/closures, but the lambda can also be broken down into an expression tree:

Expression<Func<int, int>> expr = x => x*2; // Expression tree
Func<int, int> fun = x => x*2;              // Function
delegate int MyDelegate(int x);             // Delegate
MyDelegate del = x => x*2;                  // Same as Function and Delegate

edited Aug 26 '20 at 14:45

Paul F. Wood

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answered Feb 08 '11 at 15:03

kelloti

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Note that this is only possible for a subset of lamdas: Expression-lamdas but not statement lamdas. – CodesInChaos Feb 08 '11 at 15:06
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Note that "Delegate" is a terrible name for a delegate type because it will be easily confused with System.Delegate, its base class. – Eric Lippert Feb 08 '11 at 15:20
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I apologize. I'm still drinking coffee this morning and I honestly couldn't think of another name – kelloti Feb 08 '11 at 15:22

Lambda expression vs anonymous methods

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