Question

What is actually the difference between System::String^ ex; and System::String ex1;?
I found out that the one with “^” means that it is top-level. But what does that mean?

Answer 1

System::String^ is a reference to a managed string object, System::String is a managed string object directly on the stack or inline in another class.

As mentioned in What does the caret (‘^’) mean in C++/CLI?, the ^ is a tracking reference, roughly equivalent to * for a pointer in unmanaged code. In the same way you can have unmanagedClass* foo1; and unmanagedClass foo2;, you can have System::String^ str1; and System::String str2;

When used without the ^, it follows the same rules as an unmanaged class without the *: Access methods on it with a . not a ->. Automatically cleaned up when it leaves scope (destructor in unmanaged, dispose method in managed).

One thing that does make working with managed objects without their ^ harder is that most managed objects don’t define a copy constructor or the equals operator. Neither of those would be used in C# or VB, so they generally aren’t implemented. Without them, it’s impossible to assign a new value to a variable without a ^, so you’re generally limited to constructing just a single object.