Each application settings class defines a group of application settings properties that represent information that persists between executions of the application. However, it is a settings provider—a class derived from System.Configuration.SettingsProvider—that actually provides the storage mechanism.

The System.Configuration.SettingsProviderAttribute specifies the settings provider used to provide storage for application settings properties. This attribute can be applied to the entire application settings class or individual application settings properties. A System.Configuration.SettingsProviderAttribute set at the property level will override the class-level attribute. If a settings provider is not explicitly specified, the default provider is used. For client applications, the default provider is System.Configuration.LocalFileSettingsProvider.

Setting providers cannot be determined at run time. Any run-time determination of storage methods must be coded into the settings provider class itself.