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Articles by Nizamuddin Siddiqui
Page 189 of 196
How to subscribe to an Event in C# and can we have multiple subscribers to one Event in a C#?
Events enable a class or object to notify other classes or objects when something of interest occurs.The class that raises the event is called the publisher and the classes that handle the event are called subscribers.In the EventAn event can have multiple subscribers. A subscriber can handle multiple events from multiple publishers.Events that have no subscribers are never raised.The publisher determines when an event is raised; the subscribers determine what action is taken in response to the event.Exampleclass Program { static void Main() { var video = new MP4() { Title = "Eminem" }; ...
Read MoreWhat is #if DEBUG and How to use it in C#?
In Visual Studio Debug mode and Release mode are different configurations for building your .Net project.Select the Debug mode for debugging step by step their .Net project and select the Release mode for the final build of Assembly file (.dll or .exe).The Debug mode does not optimize the binary it produces because the relationship between source code and generated instructions is more complex.This allows breakpoints to be set accurately and allows a programmer to step through the code one line at a time.The Debug configuration of your program is compiled with full symbolic debug information which help the debugger figure ...
Read MoreWhat is bin and obj folder in C#?
Whenever we write a C# code and build or run the solution it generates 2 folders −binobjThese bins and obj has the compiled codeWhy do we have 2 folders?The reason is the compilation process goes through 2 stepscompilinglinkingIn the compiling every individual file is compiled into individual unitsThese compiled files will be later linked into one unit which can be a dll or an exeWhatever happens in the compiled phase will be added into obj folderThe final compilation that is the linked phase will go into bin folderThis obj folder is used in Conditional compilation or incremental compilationEx − I ...
Read MoreWhat is the difference between IEnumerable and IQueryable in C#?
IEnumerable exists in System.Collections Namespace.IQueryable exists in System. Linq Namespace.Both IEnumerable and IQueryable are forward collection.IEnumerable doesn’t support lazy loadingIQueryable support lazy loadingQuerying data from a database, IEnumerable execute a select query on the server side, load data in-memory on a client-side and then filter data.Querying data from a database, IQueryable execute the select query on the server side with all filters.IEnumerable Extension methods take functional objects.IQueryable Extension methods take expression objects means expression tree.ExampleIEnumerabledbContext dc = new dbContext (); IEnumerable list = dc.SocialMedias.Where(p => p.Name.StartsWith("T")); list = list.Take(1); Sql statement generated for the above querySELECT [t0].[ID], [t0].[Name] FROM ...
Read MoreHow to create Guid value in C#?
A Globally Unique Identifier or GUID represents a gigantic identification number — a number so large that it is mathematically guaranteed to be unique not only in a single system like a database, but across multiple systems or distributed applications.The total number of unique keys (3.40282366×1038) is so large that the probability of the same number being generated twice is very small. For an application using 10 billion random GUIDs, the probability of a coincidence is approximately 1 in a quintillion.(1030)For example, in Retail domain if we want to generate a unique for each transaction so that a customer can ...
Read MoreHow to update the value stored in a Dictionary in C#?
In C#, Dictionary is a generic collection which is generally used to store key/value pairs. In Dictionary, the key cannot be null, but value can be. A key must be unique. Duplicate keys are not allowed if we try to use duplicate key then compiler will throw an exception.As mentioned above a value in a dictionary can be updated by using its key as the key is unique for every value.myDictionary[myKey] = myNewValue;ExampleLet’s take a dictionary of students having id and name. Now if we want to change the name of the student having id 2 from "Mrk" to "Mark". Live ...
Read MoreWhat is the difference between Foreach and Parallel.Foreach in C#?
Foreach loop in C# runs upon a single thread and processing takes place sequentially one by one. Whereas Parallel.Foreach loop in C# runs upon multiple threads and processing takes place in a parallel way. Which means it is looping through all items at once without waiting for the previous item to complete.The execution of Parallel.Foreach is faster than normal ForEach. To use Parallel.ForEach loop we need to import System.Threading.Tasks namespace.Example Live Demousing System; using System.Collections.Generic; using System.Diagnostics; using System.Threading; using System.Threading.Tasks; namespace DemoApplication{ class Demo{ static void Main(string[] args){ var animals = new ...
Read MoreHow to make a method deprecated in C#?
The Obsolete Attribute marks elements like classes, methods, properties, fields, delegates, and many others within our code as deprecated or obsolete. The attribute is read at compile time and it is used to generate a warning or an error to the developer.This attribute can help if we have ever wanted to make sure programmers use newer versions of methods. It also makes it easier when we are transitioning from older methods to newer ones. Marking an item as obsolete warns users that program elements will be removed in future versions of the code base.This attribute is found in the System ...
Read MoreWhat is an Optional parameter in C#?
By default, all parameters of a method are required. A method that contains optional parameters does not force to pass arguments at calling time. It means we call method without passing the arguments.The optional parameter contains a default value in function definition. If we do not pass optional argument value at calling time, the default value is used.Thera are different ways to make a parameter optional.Using Default ValueExample Live Demousing System; namespace DemoApplication{ class Demo{ static void Main(string[] args){ OptionalMethodWithDefaultValue(5); //Value2 is not passed as it is optional ...
Read MoreWhat is the difference between List and IList in C#?
The main difference between List and IList in C# is that List is a class that represents a list of objects which can be accessed by index while IList is an interface that represents a collection of objects which can be accessed by index. The IList interface implemented from two interfaces and they are ICollection and IEnumerable.List and IList are used to denote a set of objects. They can store objects of integers, strings, etc. There are methods to insert, remove elements, search and sort elements of a List or IList. The major difference between List and IList is that ...
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