How do you use delegates?

How do you use delegates?

You can pass methods as parameters to a delegate to allow the delegate to point to the method. Delegates are used to define callback methods and implement event handling, and they are declared using the “delegate” keyword. You can declare a delegate that can appear on its own or even nested inside a class.

What is type reflection?

Reflection provides objects (of type Type) that describe assemblies, modules, and types. You can use reflection to dynamically create an instance of a type, bind the type to an existing object, or get the type from an existing object and invoke its methods or access its fields and properties.

What does delegate mean in programming?

A delegate is a type that represents references to methods with a particular parameter list and return type. When you instantiate a delegate, you can associate its instance with any method with a compatible signature and return type.

What is CreateDelegate?

CreateDelegate(Type, Object, MethodInfo) Creates a delegate of the specified type that represents the specified static or instance method, with the specified first argument. CreateDelegate(Type, Type, String) Creates a delegate of the specified type that represents the specified static method of the specified class.

Why do we need delegates?

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.

What do you call a person who delegates?

A delegated person is a delegatee. A deputized person is a deputy. An appointed person is an appointee. A delegate is mostly an appointed or elected representative.

What is a reflection system?

Contains types that retrieve information about assemblies, modules, members, parameters, and other entities in managed code by examining their metadata. These types also can be used to manipulate instances of loaded types, for example to hook up events or to invoke methods. To dynamically create types, use the System.

What is Delegates in?

In the . NET environment, a delegate is a type that defines a method signature and it can pass a function as a parameter. The delegate object can then be passed to code which can call the referenced method, without having to know at compile time which method will be invoked.

What is delegation with example?

The definition of a delegation is a group of people who have been tasked with a specific job or given a specific purpose, or the act of assigning a specific task or purpose to a person or group of people. When a boss assigns tasks to his employees, this is an example of delegation.

What is MethodInfo C#?

The MethodInfo class represents a method of a type. You can execute a method on a class instance by calling the Invoke method. You can instantiate a MethodInfo object that represents a constructed generic method from one that represents a generic method definition by calling the MakeGenericMethod method.

What is anonymous delegate in C#?

Anonymous methods provide a technique to pass a code block as a delegate parameter. Anonymous methods are the methods without a name, just the body. You need not specify the return type in an anonymous method; it is inferred from the return statement inside the method body.

How do I get the return type of a delegate?

To construct an event handler, you need the return type and parameter types of the delegate. These can be obtained by examining the delegate’s Invoke method. The following code uses the GetDelegateReturnType and GetDelegateParameterTypes methods to obtain this information.

How to get the type of a delegate in an assembly?

(Reflection allows you to get the types in an assembly without knowing their names in advance.) Get an EventInfo object representing the event, and use the EventHandlerType property to get the type of delegate used to handle the event.

How do I add a delegate to an existing event?

Create an instance of the delegate, using the CreateDelegate method. This method is static ( Shared in Visual Basic), so the delegate type must be supplied. Using the overloads of CreateDelegate that take a MethodInfo is recommended. Get the add accessor method and invoke it to hook up the event.

Is it possible to create a delegate for a class?

Unfortunately, creating the delegate is a slow operation. We need to cache it and reuse it if we want to be super-fast. Additionally, if we are going to use this optimization technique with different classes, we need to make it more abstract. The following PropertyHelper class is a good enough solution.