Questions tagged [delegates]

Delegates can refer to several concepts. An object can rely on another (a delegate) to perform a function. Delegation can also refer to programming language feature making use of the method lookup rules for dispatching self-calls. In C#, a delegate defines which method to call when an event is triggered.

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Wait, is this… LINQ?

Context I'm working on a little project that consists in a series of Microsoft Excel add-ins (.xlam). The code being submitted for review here, is located in the ...
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using <T> in generic delegates? [closed]

Here is my problem. Do I need to give a new identifier to each delegate I write of the following delegate type? like so: or could i use one delegate that accounts for any Datatype I need to use so i ...
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Generating and calling code on the fly

Delegate This class module defines what I'm calling, in this context, a Delegate - here a function that can take a number of parameters, evaluate a result, and ...
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A custom Undo Manager

I am working on building an UndoManager in C#. The concept is to store events and property changes in a ...
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Is this a correct use of using protocols and delegate pattern in Swift?

I am trying to grasp the concept of delegates and protocols in Swift. So I have implemented my own PlayableMedia protocol with two concrete classes ...
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383 views

Delegate and Observer pattern implementation for an embedded system - copy and assignment operations

This is a follow-up to this question, which resulted in major confusion on my side regarding forwarding of arguments. Advice regarding that should probably be given in my question on SO. Overview ...
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Game passive skill system

I'm trying to create some easily accessible database of different skills. General idea is that every skill should do something different and be able to act on different things (ex. one skill which ...
7
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1answer
679 views

iOS delegation design pattern

I am working on a project that has a Model-View-Presenter structure and use the delegation design pattern that has the following structure/implementation. I would love feedback. The ViewController ...
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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: ...
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Type-Safe Event System

I have recently started writing C# from a strong JavaScript background, and found myself wanting to do something I do all the time in JavaScript: events. Since I have a type system at my disposal, I ...
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C# program that uses events

I am trying to learn C#. Please tell me if the following code respects coding standards and naming conventions because I want to write beautiful code. The purpose of this program was to help me ...
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437 views

Shopping cart using events and delegates

I am trying to learn events and delegates in C#. To do that I am trying to create a hypothetical console project where when some user submits the orders in his/her shopping cart, I need the Billing ...
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Is my Delegate defined the right way and does it need to transform to a pretty Event butterfly?

I have read so many bed time stories and ins and outs of how delegates work and why events are to be replaced with delegates (surely not all the time) and just couldn't get my head around it. I am ...
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Retry logic for delegates

I created this class which supposed to take a method and try to execute it. If it fails lets say 10 times, it will throw the original exception thrown by the delegate. Do you have any ideas for ...
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Generic method for database calls

Background Breaking from MVC, I've implemented the following architecture: POST/GET ➤ PHP ➤ Database Calls ➤ XML ➤ XSLT ➤ HTML All database interactions are ...
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Polling loop to run in a background thread

I came up with the idea of a small utility class that will poll some delegate until the response received meets some condition, upon which it will notify the main thread which can take the appropriate ...
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Delegate and Observer pattern implementation for an embedded system

I'm writing a set of simple widgets for a microcontroller application. I'd like to use the observer pattern to pass around events: when a button is clicked, when a timeout occurs - there are many uses ...
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Measuring method execution time

I want to easily measure method's execution time. Of course instead of doing something like this: ...
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1answer
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Simulate a person who is working in a quarry with classes

I build my first "bigger" program with classes. Does this look good? Or do you see something, which I could do better? Do you think I could use a delegate for changing the stones to money here? And ...
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Lock-free multiple producer single consumer message queue

For a while now I've been after a lock-free, simple and scalable implementation of a multiple producer, single consumer queue for delegates in C#. I think I finally have it. I've run basic tests on it ...
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713 views

Financial app for retrieving data over a set of dates

I'm writing a financial app that has to get data over a set of dates. The user specifies the start date, end date, and frequency from a list of choices. (daily, weekly, monthly, quarterly, semi, ...
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Several approaches to a logging class

I'm making a personal logger and so far I have come up with 3 solutions. I have them simplified in this example to highlight my dilemma. I want to know the pros and cons of my approaches and ways to ...
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Unit test if an event has been raised or not

Given the following event dispatcher code ...
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1answer
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.NET WCF Activator for sync and async calls

I decided to re-write my code responsible for WCF calls, as all of my methods had try-catch-...
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Command-line program for applying several operations on a PDF file

I am building a command-line .exe that can apply several operations on a PDF file (add text, images, resize, crop, etc). Currently, my Program.cs looks a bit like this (it uses CommandLineParser): <...
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How to simplify these delegate functions?

I'm looking for a way to simplify this code, because I could develop more overloads for TryThis I made the string and int both of class ...
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Thread-safety and delegates with generated numbers

In the main class, loops generate numbers (0~100), and when its generated number is > 20, its value is passed to the thread where it simulates some work with this number. Meanwhile, while this number ...
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Improve my Task Loops

How can I improve up this code? Is it ok to write code using Invoke and Action so liberally or is this bad? Performance is not ...
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1answer
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Stop Watch Application 2.1

After the tips from my previous review. I have come up with these changes: Separation of Concerns Use Delegates I'm asking you guys if this looks good. Other then separate out the ...
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State Machine for Character

I come today with a state machine I'm currently working on. Problem: Given any State that the Character is in, a button press or combination of button presses can modify that state in a different ...
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WeakAction Implementation

Here's my first attempt at creating a WeakAction using Expressions and Delegates. I would like it to be clear that this code was written after reading serveral blogs and taking snippets from various ...
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Asynchronous API calls with delegates and event handlers

I'm making a WindowsPhone 8 app in C#. With this an API so I can convert JSON data into useful objects. I've found a method but am wondering if it is any good at all. The problem is it's been a while ...
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Test questions - Number Generator, Linq, Delegates, Sequences

I have recently been asked to do a test prior to an interview to test my C# skills. I am fairly new to C# (6 months) and I think this showed with me producing an overly complex answer to their ...
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Cancelable thread worker

My goal was to create class, that can run external method in non blocking manner. Second requirement was to be able to abort method run if it is needed (i.e. running user script). I decided to do that ...
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1answer
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Event delegation without jQuery

I created event delegation like concept which is present in jQuery. AFAIK, event delegation is used to register an event for an element which is supposed to be added dynamically. So, in jQuery we do ...
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1answer
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Mixing Watir::Browser into RSpec

In my previous Watir question I was making a module with session_FF accepting a block. Now I want to make the same but via RSpec. Here is my try: ...
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follow-up review of a custom Undo Manager

This is a follow up review of question 'a custom Undo Manager'. After reviewing all the comments and answers, my code has been revised (completely rewritten) based on the review. Summary The ...
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Validating CSV headers against an expected list

My application (legacy code) reads a CSV input file with an expected format with regards to Column names as follows: 1st column - Should say "Marker" 2nd column - Should say "Category" 3rd column ... ...
3
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1answer
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Managing a wish list from an API

I have a class that I use to manage a list to/from an API in Swift. Using a clean code approach, I'm wondering if, how, and why I should change it when I have a class that uses it for just one or two ...
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1answer
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Sending a HttpRequest Message, and retrying in case of unauthorised

This code simply sends a HttpRequest message and, if it comes back Unauthorized, gets a new login and tries again. This code is meant to deal with the moment a ...
3
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1answer
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Removing all delegates from an event dispatcher

Given a class which is an event dispatcher whose underlying store is a dictionary of events whose key is the event type ...
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1answer
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Invoking only the last registered event handler

We are building a game and we have a dialog system. Dialogs may open and stack on top of one another. When every dialog opens, it registers itself to handle the BackButtonPressed event: ...
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1answer
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C++ delegate implementation with member functions

I have been implementing a delegate class with C++11 that supports class member functions. I am interested in knowing if there are any potential problems with this implementation. My main concern is ...
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1answer
403 views

Anything I'm missing on this delegate implementation?

Just as the question states and to be sure, am I missing anything on this? Something important/obvious that I overlooked? As is, I can save any functor, function pointer and member function pointer ...
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0answers
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Java - propagating a threadlocal by wrapping a runnable

My aim is to use a thread pool together with a thread local. I cannot use InheritableThreadLocal because the thread data is different per user and there a couple of ...
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2answers
750 views

Implementation of delegates for flight operations

I borrowed the code from this question. I'm trying to implement the delegate in that code. Below is my outcome so far. What else can be done to improve this code? Any suggestions? I would appreciate ...
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1answer
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Is it correct to use delegates as properties?

I need to create a class with two properties: LogOutput ExceptionOutput These properties (of type ...
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2answers
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Counting quiz for children

I made a game for children. This game tests the ability to count (i.e. compare numbers based on magnitude). First you must select the age of the child in the upper menu, then you need to select blocks ...
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1answer
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Delegate that selects a writable property on a generic

In the following contrived example, I have a collection of PropertyManagers that each contains selector and assigner delegates to read from and write to a property ...
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Writing strings to the screen over time

The following methods just write strings to the screen over time to make it look like a typing effect, instead of all at once. The only difference is the argument in the ...