Creates a registry key or modifies an existing registry key.
[ rdx( 
   key, 
   valuename=NULL, 
   regtype 
) ]
Parameters
- key 
 The name of the key to be created or opened.
- valuename(optional) 
 Specifies the value field to be set. If a value field with this name does not already exist in the key, it is added.
- regtype 
 The type of registry key being added. Can be one of the following: text, dword, binary, or CString.
Remarks
The rdx C++ attribute creates or modifies an existing registry key for a COM component. The attribute adds a BEGIN_RDX_MAP macro to the object that implements the target member. RegistryDataExchange, a function injected as a result of the BEGIN_RDX_MAP macro, can be used to transfer data between the registry and the data members
This attribute can be used in conjunction with the coclass, progid, or vi_progid attributes or other attributes that implies one of these.
Requirements
Attribute Context
| Applies to | class or struct member | 
| Repeatable | No | 
| Required attributes | None | 
| Invalid attributes | None | 
For more information about the attribute contexts, see Attribute Contexts.
Example
The following code adds a registry key called MyValue to the system describing the CMyClass COM component.
// cpp_attr_ref_rdx.cpp
// compile with: /LD /link /OPT:NOREF
#define _ATL_ATTRIBUTES
#include "atlbase.h"
[module (name="MyLib")];
class CMyClass {
public:
   CMyClass() {
      strcpy_s(m_sz, "SomeValue");
   }
   [ rdx(key = "HKCR\\MyApp.MyApp.1", valuename = "MyValue", regtype = "text")] 
   char m_sz[256];
};