How to convert types

Good thread ! 

Hi S,

Why don't you update your profile name with a meaningful name.

It depends on the type of expression you're converting.

In the case of numbers and other simple types, there is no implicit or explicit conversion to string. So you need to use Convert.ToString - or just ToString(). A simple cast will not work:

string st = Convert.ToString(5); // works fine

string st = 5.ToString(); // also works fine

string st = (string)5; // doesn't compile

Otherwise, the overload of Convert.ToString() which takes an 'object' parameter is used. This just returns the result of applying the ToString() method to the object or, if the parameter is null, returns an empty string.

The only cases where a cast will work for objects in general is if there is a used-defined explicit (or implicit) conversion to string for the object's type.

As the string type is sealed and inherits directly from object, there is no possibility of any sub-types or super-types (except object) existing.

Vulpes, since it seems you are an expert on this could you explain me something,.

What is the difference between 

string st = (string)...
and
string st = convert.tostring(...)

Thank you,

Again understood Vulpes and many thanks indeed!

I am aware the examples I gave were not "true to life" or "true to coding practice" they were simply intended as demos.

Two more quick points:

1. You never need to call int's constructor which always returns 0. Just  do:

  int i = 0;

2. There's no point casting or converting something which is already a string, or returns a string, to a string. Just do:

  string s = i.ToString();

 

Hi Vulpes

Think ive figured it out for example:-

int i;
i = new int();

string str;
str = (int)i.ToString(); // doesnt compile as errors with same "Cannot convert type string to int"

However...

str = (string)i.ToString(); // compiles fine as the method ToString is of type string obviously.

Thanks

on the example you gave it should've been

int i = new int();
string str = (string)i.somemethod();

and not.

int i = new int();
string str = (int)i.somemethod();

Hi Vulpes, thanks

Apologies but my explanation of the question probably wasnt the best example I could of given to get my point across...

I was enquiring re the cast conversion in a more generic way of implementation...

Am I right in saying that usual practice of implementing a cast would require putting (type) followed by the variable of the "to be" casted type, followed by the dot notation for function member access ie:-

int i = new int();
string str = (int)i.somemethod();

Thanks

S

The Encrypt method returns a byte array rather than a single byte, so you want:

byte[] enc = rsa.Encrypt();