Var and object in C#

Question

Hi friends, I want to know that if we have two variable like as var v="10"; object o="10" then what is the difference between both of them please give any explanation?

Pardeep Malik · Answer

Hello Vulpes, you are right. we can put an object to var and also a var to object. it tried both as { static void Main( string [] args) //var a = "10"; //object b; //b = a; //var c = b; //Console.WriteLine(c); //Console.ReadKey(); O var b = a; object c = b; Console .WriteLine(c); Console .ReadKey(); } both gives same result with out an error bject a= "10" ;

Vulpes · Answer

Pardeep, The last of those lines: var c = (var)b; will not compile. If you try, you'll get: "The contextual keyword 'var' may only appear within a local variable declaration". However, this compiles and runs fine: var a = 10; object b = a; var c = (int)b; 'a' is inferred to be of int type because it is being assigned the int literal 10. The value of 'a' is then boxed and assigned to the object variable 'b'. Finally, the value of 'b' is unboxed and, since it's an int, the compiler infers the type of 'c' to be int.

Pardeep Malik · Answer

Var is a data type that is predefine. but object is a root data type we can put a "var" type variable in object type it supports implicit casting in that case as var a=10; object b=a; there is no need to cast but if we retrive this value we have to cast with var type as var c=(var)b;

Vulpes · Answer

In the case of: var v = "10"; the compiler infers the type of 'v' to be string because you're assigning a string to it. 'var' is therefore strongly typed and the above line is exactly equivalent to this: string v = "10"; However, in the case of: object o = "10"; the string literal "10" is being assigned to the object variable 'o'. This is allowed because object (which is a C# alias for System.Object) is the ultimate base class of all types including string. So, here 'o' is not strongly typed (you can only call object methods on 'o', not string methods) and to retrieve the string you have to use a cast: string s = (string)o;

Var and object in C#

Answers (4)