How to check if a subKey exists

How would it be possible to check if a subKey exist in the Classes root in Registry Editor. My attemt is like follows:

//Compiler Error
'Microsoft::Win32::RegistryKey' : class does not have a copy-constructor
no conversion from 'nullptr' to 'Microsoft::Win32::RegistryKey'

Code:

---

Microsoft::Win32::RegistryKey ChecksubKey = Microsoft::Win32::Registry::ClassesRoot->OpenSubKey("This\\That");

        if( ChecksubKey != nullptr ) //Does it Exists ?
        {
                        //code here
        }

---

Shouldn't that be:

Microsoft::Win32::RegistryKey^ ChecksubKey = Microsoft::Win32::Registry::ClassesRoot->OpenSubKey("This\\That");

I don't program in C++/CLI, so I could be wrong, but it seems that you want a reference to the created object, not a copy of it.