Reflection in C#

In this article we will learn about Reflection in C#.
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Introduction

The concept of reflection is very simple in C#. Reflection is a process to collecting the information present its assembly. Reflection is a way by which a program is extracting  the metadata from its assembly. A program reflect itself when It is used metadata to modify its own behavior. It is used the  following namespace

Namespace :- System.Reflection

Following are the main classes defined in the System.Reflection namespace

Assembly Description
EventInfo This class holds information for a given event.
FieldInfo This class holds information for a given field.
MemberInfo Class is the abstract base class for classes used to obtain information about all members of a class
MethodInfo This class contains information for a given method.
ConstructorInfo This class contains information for a given constructor.

If you are using attributes in your Program, Reflection enables you to access them. You can learn about attributes in my previous article Attributes In C#

Reflection is  used for performing following task

Viewing metadata

Performing type discovery

Late binding to methods and properties

Example

using System;

using System.Collections.Generic;

using System.Text;

using System.Reflection;

namespace ReflectionExample

{

    class Program

    {

        private static int x = 5, y = 10;

 

        static void Main(string[] args)

        {

            Console.WriteLine("x + y = " + (x + y));

            Console.WriteLine("--------Please enter the name of the variable that you wish to change--------");

            string varName = Console.ReadLine();

            Type t = typeof(Program);

            FieldInfo fieldInfo = t.GetField(varName, BindingFlags.NonPublic | BindingFlags.Static);

            if (fieldInfo != null)

            {

                Console.WriteLine("The current value of " + fieldInfo.Name + " is " + fieldInfo.GetValue(null) + ". You may enter a new value now:");

                string newValue = Console.ReadLine();

                int newInt;

                if (int.TryParse(newValue, out newInt))

                {

                    fieldInfo.SetValue(null, newInt);

                    Console.WriteLine("x + y = " + (x + y));

                }

                Console.ReadLine();

            }

        }

    }

}

 

The output of following program

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Please enter the name of the variable that you wish to change. The variable is x in this example.

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The value of x is 40.

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