RoleProvider.AddUsersToRoles(String[], String[]) is called by the System.Web.Security.Roles class to associate the specified users with the specified roles at the data source. Roles are added to the configured RoleProvider.ApplicationName.
If any of the specified role names are not found for the configured applicationName, we recommend that your provider throw a System.Configuration.Provider.ProviderException.
If any of the specified user names are not associated with any of the specified role names for the configured applicationName, we recommend that your provider throw a System.Configuration.Provider.ProviderException.
If any of the specified user names is null or is an empty string, we recommend that your provider throw an exception.
If any of the specified role names is null or is an empty string, we recommend that your provider throw an exception.
If your data source supports transactions, we recommend that you include each add operation in a transaction and that you roll back the transaction and throw an exception if any add operation fails.