A delegate is a type-safe pointer that points to a method. It encapsulates method references, allows methods to be passed as parameters, and provides type safety guarantees, forcing method signatures to match delegate definitions.
The essence of delegation
A delegate is essentially a type-safe pointer that points to a method.
Detailed explanation
In C#, a delegate is a class that encapsulates a reference to a method. It allows methods to be passed as parameters to other methods and used as callback functions. Delegates also provide type safety because it enforces that method signatures match the delegate definition.
The syntax of a delegate is as follows:
<code class="c#">public delegate <return type> <delegate name>(<parameter list>);</code>
Where:
<return type>
is the return type of the delegate method. <delegate name>
is the name of the delegate. <parameter list>
is the parameter list of the delegate method. For example, to create a delegate pointing to a method named PrintMessage
, you can write:
<code class="c#">public delegate void MessagePrinter(string message);</code>
Using delegates, we can pass the method as a parameter passed to other methods. For example:
<code class="c#">public void PrintMessageWithDelegate(MessagePrinter printer, string message) { printer(message); }</code>
In this example, the PrintMessageWithDelegate
method accepts a MessagePrinter
delegate as a parameter and calls the method pointed to by the delegate to print the message.
Delegates also allow the creation of anonymous methods using lambda expressions. For example:
<code class="c#">MessagePrinter printer = (message) => Console.WriteLine(message);</code>
In this example, the lambda expression creates a delegate pointing to an anonymous method that prints the given message to the console.
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