C# : Early Binding & Late Binding : Part 23

Early Binding

---

• When we have the information of class and method and we use it to get the value at runtime is called early binding.
• Early binding can throw error during runtime
• Early binding is much more better for performance and should be alwats preferred over late binding.

• In following example the information of class is available and as well as of its type member. It is accessed by using Early binding.

 namespace Bindings  
 {  
   class Program  
   {  
     static void Main(string[] args)  
     {  
       //Early Binding  
       Arithmatic Obj = new Arithmatic();  
       Obj.NumberOne = 1;  
       Obj.NumberTwo = 2;  
     }  
   }  
   class Arithmatic  
   {  
     public Arithmatic()  
     {  
       NumberOne = 0;  
       NumberTwo = 0;  
     }  
     public int NumberOne { get; set; }  
     public int NumberTwo { get; set; }  
     public static void addNum(int a, int b)  
     {  
       Console.WriteLine(a + b.ToString() + " val");  
     }  
     public static void subNum(int a, int b)  
     {  
       Console.WriteLine(a + b.ToString() + " val");  
     }  
   }  
 }  

Late Binding

• When there is no information of class or method and we use reflection to get the value is called Late Binding.
• In reflection we send class and method / property name to get value
• With late binding there is risk of runtime exception, as it is possible that the class we are trying to access may not be present.
• Late binding is generally preferred when objects are not available during runtime.

• In following example lets assume that the class Arithmatic is not accessible, so reflection is used to get the value from the method in that class
• Note: It is assumed that the class is not accessible but we know all the properties and method present in the class.

 using System;  
 using System.Collections.Generic;  
 using System.Linq;  
 using System.Text;  
 using System.Reflection;  
 namespace Bindings  
 {  
   class Program  
   {  
     static void Main(string[] args)  
     {  
       //Late Binding  
       //loading executing assembly  
       Assembly execAssem = Assembly.GetExecutingAssembly();  
       Type ArithmaticType = execAssem.GetType("Bindings.Arithmatic");  
       //Creating instance of class  
       object ArithmaticInst = Activator.CreateInstance(ArithmaticType);  
       MethodInfo getResult = ArithmaticType.GetMethod("addNum");  
       //Create array and populate it with integers  
       object[] param = new object[2];  
       param[0] = 8;  
       param[1] = 9;  
       // Invoke the method passing in customerInstance and parameters array  
       int res = (int)getResult.Invoke(ArithmaticInst, param);  
       Console.WriteLine("Result is : ", res);  
     }  
   }  
 }