Difference Between Var And Dynamic Type Variables

In this blog, you will learn the difference between var and dynamic variable.

You might have been  asked the difference between var and dynamic variable in an interview.

Thus, I am listing the differences given below.

1. The basic difference between var and dynamic variable is that if we declare a variable with var keyword, then its type checking is done at the time of compilation due to which if you write
   

   var i; //You will get compile time error

   You need to specify the type at the time of the declaration
   

   var dummy = string.Empty;

   Dynamic is checked at the time of runtime, due to which, even if you don’t assign any value at the time of the declaration, you won’t get any compiler error.
   

dynamic test; // No Error

2. We can pass dynamic type as a part of method parameterdeclaring.
   

   public void IsValidInput(dynamic input) //Correct
   Public void IsValidInput(var input) //Error

3. If you need to write a generic method, you can make use of dynamic type to defer the type check until run time
   

   Public string GenericAdd(dynamic input) {
       input.Message = ”Generic Add Method”; //No error as your parameter type is dynamic
       return input.Message;
   }
   Suppose I have two different classes having Message properties
   Public class Test1 {
       Public string Message {
           get;
           set;
       }
       Public int counter {
           get;
           set;
       }
   }
   Public class Test2 {
       Public string Message {
           get;
           set;
       }
   }
   //Call GenericAdd method
   Console.WriteLine(GenericAdd(new Test1()));
   Console.WriteLineGenericAdd(new Test2());

I believe the above explanation will help you.