Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [delegates]

The tag has no usage guidance.

0
votes
2answers
49 views

Turn an asynchronous delegate pattern into a blocking method

I have to use a built-in API that works like this class MyAPIWrapper { func callAPI() { apiObj.delegate = self apiObj.doWork() // returns immediately, eventually calls self.delegate....
0
votes
2answers
151 views

Design issue with delegation, inheritance and dependency injection

My question relates to usage of delegation together with inheritance and dependency injection. I have a MailerService class that requires a delegate in order to do its job. Furthermore, I have a ...
2
votes
2answers
812 views

Fundamental differences between a List<Action> vs Action

Is there any fundamental difference between to using an action and a list of actions? Seeing that action is a delegate and therefore is a list itself. For instance: List<Action> ...
0
votes
1answer
193 views

How to generalize which delegate is being used from an interface

I currently have the following set up where I have 2 or 3 classes implementing IZoneController and I have a set of conditions determining which function they need to execute when called. I first ...
-1
votes
3answers
238 views

Refactoring - Resolve dependencies between legacy code used by third parties

I am developing two libraries in .Net Firs one it's a library with core functionality (named it Library.Core.dll) Let's focus in User class public class User { //set of constructors and ...
4
votes
2answers
320 views

Is there an Ideal way of storing namespace-related elements?

In the title, with namespace-related elements, I refer to Enums, Delegates and other elements that do not belong to a single class, but to the whole namespace, or application. I know that I can cram ...
11
votes
5answers
3k views

Using Func instead of interfaces for IoC

Context: I am using C# I designed a class, and in order to isolate it, and make unit testing easier, I am passing in all its dependencies; it does no object instantiation internally. However, instead ...
3
votes
1answer
857 views

Is it possible to method-inject an object call?

Consider this example of method injection: static void SaveEmail(Func<string> getEmailFunction) { dbcontext.SaveEmail(getEmailFunction()); } static string GetEmail() { var frmUser = ...
1
vote
2answers
143 views

What is 'better' - An event that tells you that something happened or accepting a delegate to be called when the event triggers internally?

I am writing a collection that accepts a time parameter, the purpose is that after that specified amount of time have passed the element won't be present in the collection. I want the user of this ...
0
votes
0answers
51 views

If a delegate contains a tail call request, what happens?

Simply put, what happens when I have a delegate, that delegate contains a method with a tail call request, and then I call it from a non-tail position? If I called the method directly, it would ...
8
votes
3answers
2k views

Why aren't properties implicitly convertible to delegates

We all know that properties in C# get compiled to actual plain old methods. But unlike method(-group)s, they can't be given as arguments to other methods that expect a delegate like a Func<T> or ...
0
votes
1answer
194 views

Is it a good practice to use a Service without Delegate?

I have a simple REST application with a single controller. The application needs to fetch data from a Database, convert it to JSON and return this to the caller. I need to decide what layers I should ...
4
votes
1answer
131 views

Using delegates as named lambdas

Suppose we have a domain in which we can generalise some operation by passing in a function, like the Select \ map functions. Now suppose that the function we pass in has some domain specific name, ...
5
votes
3answers
2k views

Differences between “first-class function” mechanisms

Some languages (Javascript, Python) have the notion that a function is an object: //Javascript var fn = console.log; This means that functions can be treated like any other object (first-class ...
3
votes
1answer
867 views

Strategy Pattern not sufficient for my problem?

Let me sketch the situation: I have multiple users, with certain properties (2 enums) For each user I need to fetch data, for some with some basic filtering, for some extended filtering (= basic ...
0
votes
1answer
3k views

What is the difference between Adapter and Delegation design pattern?

I am very confused about Adapter and Delegation design pattern. In Adapter pattern we bring an intermediate class to interact with another class. And in Delegation pattern we also bring an ...
2
votes
1answer
125 views

how to split up a delegate class

I have a communication class that incapsulates all the apis of a remote application. This class happens to be a delegate class because it is interchangeable with another one (the remote application ...
1
vote
3answers
889 views

Using delegates to avoid duplicate creation of resources

I'm writing a PCL that uses an HttpClient to go visit a few sites and extract data from them. My initial code looked like this: public static class Download { public async static Task<byte[]&...
2
votes
3answers
239 views

Many different classes that need similar functionality. Best approach?

I have many (at the moment around 30) different message classes in an application I am creating. Each of these messages need to be serialized and deserialized. However, the process of serializing and ...
3
votes
2answers
348 views

Why aren't field-like events implemented as a list of delegates?

tl;dr: Why are field-like events implemented as a single delegate field? Wouldn't it be more straight-forward to use a list of delegates, thereby eliminating the null special case and avoiding all the ...
2
votes
1answer
874 views

Avoiding closures

I have a data structure in the form of a tree. Each node represents a cardboard box. The boxes can contain child boxes. public class CardboardBox { public int Id {get; set;} public int ...
0
votes
1answer
96 views

Is it ok for a for a View to dismiss itself?

Currently, I'm working on a project in which a view is dismissing itself. While talking to another programmer on the team for this project, he said that it's fine (in that it behaves correctly), but ...
2
votes
1answer
695 views

Generic delegates (C#) in Scala?

I wanted to know if there is an equivalent of the C# generic delegates in Scala. The reference website is: http://msdn.microsoft.com/en-us/library/dd233060.aspx I'm trying to make a complete ...
2
votes
2answers
1k views

Understanding C# Delegates Structure

I've been trying to understand C# delegates using Pro C# 5. In short, the author describes the motivation for delegates as a structured way of dealing with function pointers and callbacks or two-way ...
0
votes
0answers
50 views

Own Exception or Delegation design pattern to exit a program?

I am writing an application in Java which use MVC pattern design. I have 4 major classes: Main, Controller, Model, View. Main initialize the other three and run launchMenu() in a infinite loop, a ...
0
votes
0answers
403 views

Delegate method privately called from delegate itself?

One has established design patterns so ingrained in their brain, that when sometimes somebody does something unexpected, it is a revelation. My colleague in an iOS project did call the delegate ...
0
votes
1answer
64 views

Is it fine for a class that creates objects to delegate them?

I have a large list of intercommunicating components; so I decided to have one class create all of them and then subsequently delegate them to other classes to facilitate finer tweaking and wiring ...
2
votes
0answers
148 views

Run a function when a function in a list is executed?

Goal: I'm currently doing an MVC project and I have this method to update the ViewBag (based on previous actions of the user). I would like to call this function whenever a certain list of MVC Actions ...
8
votes
4answers
3k views

C# Delegates are immutable - but why does that matter?

This is a followup question to this other question. Background Working from the MSDN Delegates Tutorial (C#), I see the following: Note that once a delegate is created, the method it is ...
25
votes
7answers
18k views

Why would I ever use delegates if I'm not doing events? [duplicate]

I am trying to learn how to do events in C#, and according to the MSDN Events tutorial, Events are declared using delegates. If you have not yet studied the Delegates Tutorial, you should do so ...
5
votes
6answers
3k views

Do delegates defy OOP

I'm trying to understand OOP so I can write better OOP code and one thing which keeps coming up is this concept of a delegate (using .NET). I could have an object, which is totally self contained (...
3
votes
3answers
3k views

Why use protocol, not call the method directly?

I was asked this question in an interview. For eg: UITableviewDelegate protocol has CellForRowAtIndexpath. Why make it a delegate method in a protocol not a method in the UITableView class and call it ...
11
votes
2answers
22k views

What is Delegation and why is it important in iOS programming?

At the moment I am teaching myself iOS programming, and one concept I find really hard to wrap my head around is delegation. What is it? Why and how is it used? What is the advantage? The technical ...
3
votes
2answers
850 views

Template method within one class without subclasses or inheritance

I have an algorithm with mostly invariant parts that needs to be reused within one class so as to stay DRY. Code duplication with repeating method structure public void save(String key, int value) {...
9
votes
5answers
20k views

What are the advantages of the delegate pattern over the observer pattern?

In the delegate pattern, only one object can directly listen to another object's events. In the observer pattern, any number of objects can listen to a particular object's events. When designing a ...
7
votes
2answers
4k views

MVC and delegation

I am a beginning iOS programmer and use the Model-View-Controller model as a design pattern: my model doesn't know anything about my view (in order to make it compatible with any view), my view doesn'...
4
votes
2answers
3k views

Strategy vs Delegates

Can the Strategy design pattern entirely replace delegates? In Java, for example, there are no delegates. Is it possible to gain all the features of delegates by using Strategy design pattern? Edit:...
5
votes
1answer
1k views

Need to process 2 million 100k messages per second and route them to a particular event, delegate or multicast delegate

I need to process 2 million messages per second (perhaps in a scale out configuration) and route each message to a N delegates or multicast delegates. Question How should I structure my application ...
6
votes
2answers
594 views

Delegates and events

What is the difference between public delegate void SecondChangedHandler(Object clock, TimeInfoEventArgs ti); public event SecondChangedHandler OnSecondChanged; and public event EventHandler<...
4
votes
2answers
2k views

How do delegates fit into ASP.NET?

A developer told me they used delegates to bind most of their events in ASP.NET. Until then, I did not even know it was possible to use delegates in ASP.NET in a meaningful way. My understanding ...
7
votes
4answers
701 views

Can you overuse delegates and events

I've just started getting to grips with event driven programming and I'm finding delegates and events to be very useful. Since starting to see the potential I've began using them all the time to solve ...
2
votes
5answers
668 views

Delegate vs Method

Is there any advantige using delegates instead of methods? For example: public void LoginAuthenticate(object sender, AuthenticateEventArgs e) { if (Membership.ValidateUser(lgUserLogin.UserName, ...
2
votes
2answers
703 views

Delegate pattern for retrieving data v.s. using simple setters

I am considering using the Delegate Pattern to get some data necessary for an operation. There are a few different pieces of data that the algorithm needs to run, but they all have default values that ...
14
votes
10answers
51k views

Real world use of C# Delegates [closed]

I think that I conceptually understand C# delegates, however, I am struggling to find a real world example where they would be useful. Can you provide some answers detailing how C# delegates were ...