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User-settings class for ATL/WTL projects

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3 Apr 2001 96.7K   458   38   12
A helper class for storing user settings in the Registry, similar to MFC's CWinApp

User-settings class for ATL/WTL Projects

WTL is a great framework for putting together small, lightweight applications, but I miss some of the helpful features of MFC. One of these is the ability to save user settings in the registry. So I made this class to save me the hassle of calling the registry API by hand. All you need to do is derive your main user-interface class (either your frame window or view) from CAppSettings, like so:

class CMainFrame : public CAppSettings, CFrameWindowImpl<CMainFrame>, ...

After that, one call to specify the name of the key your settings will be stored under and you're away. You can set and retrieve strings, DWORDs and structs, and they can be stored under HKEY_LOCAL_MACHINE or HKEY_CURRENT_USER. In either case, your settings will be stored in a subkey of Software.

Functions

Use this function to specify the root key for your settings. Typically you will want to use something like "companyname\\appname".

  • void SetRegKey(LPCTSTR lpszKey)

Use these functions for storing values in the registry. Replace XXX with "Machine" or "User", depending on whether you want them stored under HKEY_LOCAL_MACHINE or HKEY_CURRENT_USER. In each of the functions below, lpszSection is the name of a further subkey which will be added to the string you specified in SetRegKey. So the entire key path will look like this:

[HKLM / HKCU]\Software\keyname\section
name\value

  • BOOL WriteXXXProfileDword(LPCTSTR lpszSection, LPCTSTR lpszEntry, DWORD dwVal)
  • BOOL WriteXXXProfileString(LPCTSTR lpszSection, LPCTSTR lpszEntry, LPCTSTR lpszVal)
  • template <class T> BOOL WriteXXXProfileStruct(LPCTSTR lpszSection, LPCTSTR lpszEntry, T& obj)

Use these functions to retrieve a value from the registry, or a default value if it isn't there. The function to store a user-defined struct cannot retrieve a default value, and only returns TRUE or FALSE to indicate whether or not the call succeeded.

  • DWORD GetXXXProfileDword(LPCTSTR lpszSection, LPCTSTR lpszEntry, DWORD dwDefault = 0)
  • CString GetXXXProfileString(LPCTSTR lpszSection, LPCTSTR lpszEntry, LPCTSTR lpszDefault = NULL)
  • template <class T> BOOL GetXXXProfileStruct(LPCTSTR lpszSection, LPCTSTR lpszEntry, T& obj)

That's it! I hope you find it useful.

License

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Comments and Discussions

 
GeneralUpdated for VC++ .NET Pin
negotiator22-Jun-03 19:50
negotiator22-Jun-03 19:50 
GeneralRe: Updated for VC++ .NET Pin
Rob Staveley7-May-04 2:14
Rob Staveley7-May-04 2:14 
GeneralMFC Pin
2-Oct-01 0:27
suss2-Oct-01 0:27 
GeneralOoouuuccchhh Pin
Tomaz Stih4-Mar-01 23:33
Tomaz Stih4-Mar-01 23:33 
GeneralRe: Ooouuuccchhh - damn parser ate most important characters Pin
Tomaz Stih4-Mar-01 23:36
Tomaz Stih4-Mar-01 23:36 
GeneralRe: Ooouuuccchhh Pin
Peter Kenyon5-Mar-01 11:57
Peter Kenyon5-Mar-01 11:57 
Thanks for your comments.

> Using inheritance in a way you do in C++ means establishing IS-A relationship. This
> means that your main frame is an app setting. Nedless to say, this is extremely ugly,
> plus you use multiple inheritance.
>
> Instead you should use HAS-A relationship and bind it to your application, not your main
> frame.

Actually it doesn't matter what class you bind it to, it doesn't have to be the main frame at all. You could derive a class from CComModule and associate it with that.

You don't need to use multi inheritance, although if you are using ATL/WTL most of your classes will be multi inheritance anyway. You can make CAppSettings a member of a containing class. So you can use whatever methodology you prefer.

> I had this neat idea about implementing registry values based on templates (if anyone
> cares to play with it?). Compliant with ATL/WTL philosophy one could have something like:
>
> UserSetting<int> iNrOfOpenedWindows;
> MachineSetting<std::string> sCustomerIdForAutoUpdate;
>
> Then one could say iNrOfOpenedWindows=1 (treat it as integer) and
> iNrOfOpenedWindows.Save("MyCompanyName/MyAppKey"). You could provide different Save/Load
> pre-implementations for some known types using C++ traits...

I like this idea. Why not have something like this:

UserSetting<int, _T("MyCompany\\Screen")> iNrOfOpenedWindows

Then put the code to load the value in the constructor and the code to save the value in the destructor. That way the value is loaded when the app starts up and saved when it terminates.

Peter

GeneralRe: Ooouuuccchhh Pin
Tomaz Stih5-Mar-01 23:52
Tomaz Stih5-Mar-01 23:52 
GeneralRe: Ooouuuccchhh Pin
Peter Kenyon6-Mar-01 11:51
Peter Kenyon6-Mar-01 11:51 
QuestionArchaic? Pin
DBJ22-Aug-00 10:03
DBJ22-Aug-00 10:03 
AnswerRe: Archaic? Pin
Peter31-Aug-00 19:11
Peter31-Aug-00 19:11 
AnswerRe: Archaic? Pin
aaa28-Oct-00 10:54
aaa28-Oct-00 10:54 
GeneralHas a dependency on CString Pin
Peter Kenyon6-Jul-00 20:02
Peter Kenyon6-Jul-00 20:02 

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