Question

Right now I’m having it with Guids.

I certainly remember that throughout the code in some places this implicit conversion works, in others it does not. Until now I fail to see the pattern.

How the compiler decides when it cannot? I mean, the type method Guid.ToString() is present, isn’t it called whenever this transformation is needed?

Can someone please tell me under what circumstances this transformation is done automatically and when I have to call myInstance.ToString() explicitly?

Answer 1

In short, when there is an implicit or explicit conversion operator defined:

class WithImplicit {     public static implicit operator string(WithImplicit x) {         return x.ToString();} } class WithExplicit {     public static explicit operator string(WithExplicit x) {         return x.ToString(); } } class WithNone { }  class Program {     static void Main() {         var imp = new WithImplicit();         var exp = new WithExplicit();         var none = new WithNone();         string s1 = imp;         string s2 = (string)exp;         string s3 = none.ToString();     }  }