CODEWITHSUNDEEP
c#
Embedd_0913
Embedd_0913

Reputation: 16555

Casting to string versus calling ToString

object obj = "Hello";
string str1 = (string)obj;
string str2 = obj.ToString();

What is the difference between (string)obj and obj.ToString()?

Upvotes: 45

Views: 47722

Answers (5)

Mac
Mac

Reputation: 8339

  • (string)obj casts obj into a string. obj must already be a string for this to succeed.
  • obj.ToString() gets a string representation of obj by calling the ToString() method. Which is obj itself when obj is a string. This (should) never throw(s) an exception (unless obj happens to be null, obviously).

So in your specific case, both are equivalent.

Note that string is a reference type (as opposed to a value type). As such, it inherits from object and no boxing ever occurs.

Upvotes: 51

Nick Masao
Nick Masao

Reputation: 1108

If its any help, you could use the 'as' operator which is similar to the cast but returns null instead of an exception on any conversion failure.

string str3 = obj as string;

Upvotes: 18

amr osama
amr osama

Reputation: 1149

ToString() is object class method (the main parent class in .net) which can be overloaded in your class which inherits from object class even if you didn't inherited from it.

(string) is casting which can be implemented in the class it self, the string class so you don't have ability on it.

Upvotes: 1

Guillaume
Guillaume

Reputation: 13138

(string)obj cast the object and will fail if obj is not null and not a string.

obj.ToString() converts obj to a string (even if it is not a string), it will fail is obj is null as it's a method call.

Upvotes: 2

ChrisF
ChrisF

Reputation: 137128

At the most basic level:

(string)obj will attempt to cast obj to a string and will fail if there's no valid conversion.

obj.ToString() will return a string that the designer of obj has decided represents that object. By default it returns the class name of obj.

Upvotes: 9

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