how to feed all methods with one instance of required class

[sim]

there is a class that other classes use it in their methods . I want to give all methods just one instance of the class during a request . update : saying during a request I mean : when a user makes a request to the server to load a webpage (beginRequest) , several events and methods would be called and raised . many of them need my class to save some data into a database . instead of instantiating my class in each method or page and making several transactions to the database , I want all methods to use just one instance that buffers those data and at the end of request insert all data into database once . and these repeat with the next request