Better ways for type casting in C#

Question

Case 1: we can convert type by the following ways .....

1. First way

       int someInt = 10;
       double someDouble = (double) someInt;
   

2. Same thing in second way

       int someInt = 10;
       double someDouble = Convert.ToDouble(someInt);
   

Case 2: We can convert somethings into string by the following ways .......

1. First way

       int someInt = 10;
       string someString =  someInt.ToString();
   

2. Second way

       int someInt = 10;
       string someString =  someInt.ToString(CultureInfo.InvariantCulture);
   

Now my question is which one is good?? I am asking this question because ReSharper always gives me suggestion like 2nd way for both cases. I don't which one should I follow.

Answer 1

1. Case 1 - both ways are equal, 1st way being little bit faster.
2. Case 2 - 1st way could be dangerous, since int.ToString() uses Culture.CurrentCulture as an argument (and so results can vary from computer to computer):

as in:

someInt.ToString() == someInt.ToString(CultureInfo.CurrentCulture);