See Also: RegistryKey Members
The registry acts as a central repository of information for the operating system and the applications on a computer. The registry is organized in a hierarchical format, based on a logical ordering of the elements stored within it (please see Microsoft.Win32.Registry for the base-level items in this hierarchy). When storing information in the registry, select the appropriate location based on the type of information being stored. Be sure to avoid destroying information created by other applications, because this can cause those applications to exhibit unexpected behavior, and can also have an adverse effect upon your own application.
Registry keys are the base unit of organization in the registry, and can be compared to folders in File Explorer. A particular key can have subkeys, just as a folder can have subfolders. Each key can be deleted, as long as the user has the appropriate permissions to do so, and the key is not a base key or at the level directly under the base keys. Each key can also have multiple values associated with it (a value can be compared to a file), which are used to store the information — for example, information about an application installed on the computer. Each value holds one particular piece of information, which can be retrieved or updated when required. For instance, you can create a Microsoft.Win32.RegistryKey for your company, under the key HKEY_LOCAL_MACHINE\Software, and then a subkey for each application that your company creates. Each subkey holds the information specific to that application, such as color settings, screen location and size, or recognized file extensions.
Note that information stored in the registry is available to other applications and users, and therefore should not be used to store security data or critical application information.
Do not expose Microsoft.Win32.RegistryKey objects in such a way that a malicious program could create thousands of meaningless subkeys or key/value pairs. For example, do not allow callers to enter arbitrary keys or values.
Starting in the net_v40_long, the length of a registry key is no longer limited to 255 characters.