This class is the starting point when using the Windows registry, which is the central repository used by most Windows applications for storing user-specific settings and preferences. Each static field of this class represents a root RegistryKey object, which has values and multiple levels of subkeys. These keys are read-only, but can be manipulated using the methods of the RegistryKey class.

Most applications store their settings in CurrentUser (HKEY_CURRENT_USER). The recommended standard is to use the Software subkey, create a subkey for your organization, and then create a subkey for each specific application (for example, Internet Explorer preferences are stored in HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer). Analogous global settings that should affect all users on the current computer can be placed in a similar subkey in LocalMachine (HKEY_LOCAL_MACHINE). For example, setup programs often use this key to store information about installed applications. The full collection of user settings for all the users of the current computer can be retrieved from the Users key, as can the default settings for new users, which are contained in the .DEFAULT subkey of users. CurrentUser is actually a mapped subkey of Users, much as CurrentConfig is a subkey of LocalMachine.

The ClassesRoot key contains information used for Windows 3.1-compatible DDE and OLE support. Information for file viewers, Windows Explorer extensions, and file associations is also stored in this key. You can use the PerformanceData key to retrieve performance-related information. This data is not actually stored in the registry. Instead, it is automatically collected from the appropriate system object managers when this key is accessed. Lastly, the DynData key is used to support Virtual Device Drivers (VxDs) and allow them to provide real-time data to remote Win32 applications. It is used only in Windows 95, 98, and ME systems.

Much more information about the system registry is available from Microsoft's Windows platform documentation.

public sealed class Registry {
// Public Static Fields
   public static readonly RegistryKey ClassesRoot;
// =HKEY_CLASSES_ROOT [0x80000000]
   public static readonly RegistryKey CurrentConfig;
// =HKEY_CURRENT_CONFIG [0x80000005]
   public static readonly RegistryKey CurrentUser;
// =HKEY_CURRENT_USER [0x80000001]
   public static readonly RegistryKey DynData;
// =HKEY_DYN_DATA [0x80000006]
   public static readonly RegistryKey LocalMachine;
   // =HKEY_LOCAL_MACHINE [0x80000002]
   public static readonly RegistryKey PerformanceData;
// =HKEY_PERFORMANCE_DATA [0x80000004]
   public static readonly RegistryKey Users;
// =HKEY_USERS [0x80000003]
}