delegate in c# .what its purpose?

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what is the main purpose of delegates in .net?we dont have another approch in place of delegates.what its job?

thanx for ur answers

Posted 16-Nov-11 1:45am

syedkhaleel

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Rob Philpott · Answer 1 · 2011-11-16T01:52:00

Solution 1

You need to read a book Sir! Really, there's no point spouting on about it here, there's so much on the net already.

You could start here:

http://msdn.microsoft.com/en-us/magazine/cc301810.aspx[^]

Posted 16-Nov-11 1:52am

Rob Philpott

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Sergey Alexandrovich Kryukov 16-Nov-11 8:00am

I was afraid even to open this page :-) Right, there is no point, my 5.
--SA

Sergey Alexandrovich Kryukov 16-Nov-11 8:12am

Even though I voted 5, I want to add a note: this article does not explain important things.

I actually did not see a single Microsoft article which tells all the truth about delegates. Please see my comment to the solution (pretty much incorrect) by Rais. I put some interesting detail in my article: "Dynamic Method Dispatcher", http://www.codeproject.com/KB/dotnet/DynamicMethodDispatcher.aspx. Please see -- there are some facts which are easy to check up but most developers did not suspect about.
--SA

Rob Philpott 16-Nov-11 8:27am

Didn't read it to be honest, but the title sounded like a starting point. When I started with .NET the first book I read was.. can't remember, but the second edition of it was called CLR via C# by Jeffrey Richter. I think its now in its third revision. Should be compulsary reading. Also, C# in a nutshell by Josepth Albahari is an awesome read and deadly concise. If anybody wants to learn about things like delegates you couldn't do better than reading those two. Will check your link out too. :)

RaisKazi · Answer 2 · 2011-11-16T01:59:00

Solution 3

Delegate is a Pointer to a Function/Method, which holds the reference of the Function/Method. (I know its too theoretical :))

Information of Delegates on MSDN.
http://msdn.microsoft.com/en-us/library/ms173171.aspx

CodeProject Article on Delegates.
Events and Delegates simplified

Posted 16-Nov-11 1:59am

RaisKazi

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Sergey Alexandrovich Kryukov 16-Nov-11 8:07am

(Sight) Rais, this is not true. If here is some truth in it, but only in zero approximation. Do you know that an instance of a delegate is a class (surprise!)? It provides access to a container called invocation list. That is, each delegate instance is potentially multicast. And each single handler can be a pointer only for static members. For non-static members, it's at least two pointers: one points to code, another one references "this". But in fact it's even more complex.
Pretty far from you explanation, isn't it? How about your understanding?
--SA

Sergey Alexandrovich Kryukov 16-Nov-11 8:13am

I put some interesting detail in my article: "Dynamic Method Dispatcher", http://www.codeproject.com/KB/dotnet/DynamicMethodDispatcher.aspx. Please see -- there are some facts which are easy to check up but most developers did not suspect about.
--SA

RaisKazi 16-Nov-11 8:26am

Sure, will go through it.

RaisKazi 16-Nov-11 8:23am

It's a wide topic altogether. Agree, its a complex concept(which is becoming more complex day by day :)), Microsoft has introduced "Predicate Delegates" from .Net Framework 2.0. I think, that CodeProject Article may help OP to begin with.(Ideally Google/MSDN would have revealed all, if OP would know how to search on Google/MSDN.)

Sergey Alexandrovich Kryukov 16-Nov-11 15:00pm

This is a very advanced matter (but I don't say "complex", just advanced; main problem is lack of detailed documentation) which is not, strictly speaking, required to be known in detail just for using delegates, but the main ideas must be understood.
--SA

Paulo Zemek · Answer 3 · 2011-11-16T02:19:00

The main purpose is to hold information on how to call a method (or group of methods) with a given signature (parameter types and result type).
Alternatives? Sure. You can always create an interface with a Run method.
But delegates are still faster than interfaces.

They are largely used on Events, but you can use them every time you want to receive a "function" as a parameter. One of the overloads of List.Sort method receives a delegate, so you can do your on comparison.

rempackraja · Answer 4 · 2011-11-16T03:17:00

Delegates have the following properties:

Delegates are similar to C++ function pointers, but are type safe.

Delegates allow methods to be passed as parameters.

Delegates can be used to define callback methods.

Delegates can be chained together; for example, multiple methods can be called on a single event.

Methods don't need to match the delegate signature exactly. For more information, see Covariance and Contravariance

C# version 2.0 introduces the concept of Anonymous Methods, which permit code blocks to be passed as parameters in place of a separately defined method.

nsk_saravana · Answer 5 · 2011-11-16T01:52:00

Solution 2

Delegate will be useful whenever r going to use USER CONTROL in the aspx page.This the real time usage.
You can search in this way and you can find more code with examples.

Posted 16-Nov-11 1:52am

nsk_saravana

Comments

Rob Philpott 16-Nov-11 7:55am

Hmm. Delegates have nothing to do with USER CONTROLS, aspx or real time usage, so I don't think that's helpful to be honest.

[no name] 16-Nov-11 7:56am

Delegates have no connection with user controls. Perhaps you need to do research also.

[no name] 16-Nov-11 7:58am

dont provide wrong answers please

Sergey Alexandrovich Kryukov 16-Nov-11 8:03am

Agree with you and others. This is easier to claim than to meet, but at least it's good to avoid answering in the fields which a person is not comfortable with. There are delusions though...
--SA

delegate in c# .what its purpose?

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