What is Dependency in C#?

Question

How a class dependent to another class? Any example so that clearly explain in interview. Now what is Dependency injection? they reduces tightly coupled to loosley coupled so code maintaince is easy so how any example?

Manas Mohapatra · Answer

Dependency Injection (DI) is a design pattern that allow us to develop loosely coupled code. DI is a great way to reduce tight coupling between software components. It can be implemented in following ways: Through Constructor Through Method Through Property We will implement Dependancy Injectio using constructor: public class ExcpetionLogger { private ILogger _logger; public ExcpetionLogger(ILogger aLogger) { this ._logger = aLogger; } public void LogException(Exception aException) { this ._logger.WriteToLog(aException.Message); } } public interface ILogger { void WriteToLog( string text); } public class LogToFile : ILogger { public void WriteToLog( string text) { Console.WriteLine( Writing data in text file:  + text); } } public class LogToDB : ILogger { public void WriteToLog( string text) { Console.WriteLine( Writing data in DB:  + text); } } Let's call the method: try { //code to export data from files to database. } catch (IOException ex) { ExcpetionLogger excpetion1 = new ExcpetionLogger( new LogToFile()); excpetion1.LogException(ex); // Writing data in text file: ExcpetionLogger excpetion2 = new ExcpetionLogger( new LogToDB()); excpetion2.LogException(ex); // Writing data in DB: } In preceding code we are passing the instance of Loggerer class through constructor. And it logs the the exception message based object instance. First we are passing to log the messge and secondly we are passing to log message in DB. It is totally independent. You can also implement dependency injection using third party library like autofac microsoft Ninject etc. .

Sandeep Singh Shekhawat · Answer

Dependency Injection (DI) is a pattern where objects are not responsible for creating their own dependencies. Dependency injection is a way to remove hard-coded dependencies among objects making it easier to replace an object's dependencies either for testing (using mock objects in unit test) or to change run-time behavior. There are three types of dependency injections: Constructor Dependency Injection Setter Dependency Injection Interface Dependency Injection There are some articles which explained dependencyinjection and Inversion of control. Please have a look on below. 1.http://www.c-sharpcorner.com/UploadFile/3d39b4/constructor-dependency-injection-pattern-implementation-in-c/ 2. http://www.c-sharpcorner.com/UploadFile/3d39b4/crud-operations-using-the-generic-repository-pattern-and-dep/ 3.http://www.c-sharpcorner.com/article/dependency-inject-using-ninject-ioc-in-console-application/ You can download source code as well to follow below links: 1.https://gallery.technet.microsoft.com/CRUD-Operations-Using-0aa46470 2.https://code.msdn.microsoft.com/Dependency-Injection-in-e7adb082

Vinay Singh · Answer

When you use use interface class in a class at that time you need to use the implement the interface. Now what is Dependency injection ? Dependency injection is used to create a single instance for a class at the time of accessing the application. so no requirement of creating instance again and again

Sandeep Singh Shekhawat · Answer

Ashish Follow the link mentioned in theprevious thread in which mentioned practical andreal life example.

Ashish Verma · Answer

Hi I know what is dependency Injection and how many type we can implement but i want to know easy example so can explain it better way.