Search results
Results from the WOW.Com Content Network
There is a list of delegates maintained internally, and when the multicast delegate is invoked, the list of delegates is executed. In C#, delegates are often used to implement callbacks in event driven programming. For example, a delegate may be used to indicate which method should be called when the user clicks on some button.
C# provides type-safe object-oriented function pointers in the form of delegates. class Program { // Delegate type: delegate int Operation ( int a , int b ); static int Add ( int i1 , int i2 ) { return i1 + i2 ; } static int Sub ( int i1 , int i2 ) { return i1 - i2 ; } static void Main () { // Instantiate the delegate and assign the method to it.
As a precursor to the lambda functions introduced in C# 3.0, C#2.0 added anonymous delegates. These provide closure-like functionality to C#. [3] Code inside the body of an anonymous delegate has full read/write access to local variables, method parameters, and class members in scope of the delegate, excepting out and ref parameters.
Translating the implicit this into an explicit parameter, the call (in B, with a a delegate) a.foo() translates to A.foo(b), using the type of a for method resolution, but the delegating object b for the this argument. Using inheritance, the analogous code (using capital letters to emphasize that resolution is based on classes, not objects) is:
In the delegate pattern, this is instead accomplished by explicitly passing the original object to the delegate, as an argument to a method. [1] " Delegation" is often used loosely to refer to the distinct concept of forwarding , where the sending object simply uses the corresponding member on the receiving object, evaluated in the context of ...
Delegate (CLI), a form of type-safe function pointer used by the Common Language Infrastructure (CLI), specifying both a method to call and optionally an object to call the method on. See also [ edit ]
C# has support for strongly-typed function pointers via the keyword delegate. Like the Qt framework's pseudo-C++ signal and slot, C# has semantics specifically surrounding publish-subscribe style events, though C# uses delegates to do so.
A new pseudo-type dynamic is introduced into the C# type system. It is treated as System.Object, but in addition, any member access (method call, field, property, or indexer access, or a delegate invocation) or application of an operator on a value of such type is permitted without any type checking, and its resolution is postponed until run-time.