What is an application object?
Application object is used when we want data to be shared across users globally in an ASP.NET application.
What is the use of cache object?
It also does the same thing as the application object i.e. sharing and caching global data across ASP.NET pages in a web application.
What is the difference between Cache object and application object?
The main difference between the Cache and Application objects is that the Cache object provides features, such as dependencies and expiration policies.
How can get access to cache object?
The Cache object is defined in the ‘System.Web.Caching’ namespace. You can get a reference to the Cache object by using the Cache property of the HttpContext class in the ‘System.Web’ namespace or by using the Cache property of the Page object.
What are dependencies in cache and types of dependencies?
When you add an item to the cache, you can define dependency relationships that can force that item to be removed from the cache under specific activities of dependencies.Example if the cache object is dependent on file and when the file data changes you want the cache object to be update. Following are the supported dependency: -
- File dependency: - Allows you to invalidate a specific cache item when a disk based file or files change.
- Time-based expiration: - Allows you to invalidate a specific cache item depending on predefined time.
- Key dependency:- Allows you to invalidate a specific cache item depending when another cached item changes.
Can you show a simple code showing file dependency in cache?
Above given method displayAnnouncement() displays banner text from Announcement.txt file which is lying in application path of the web directory. Above method, first checks whether the Cache object is nothing, if the cache object is nothing then it moves further to load the cache data from the file. Whenever the file data changes the cache object is removed and set to nothing.
See following video on ASP.NET Authentication, Authorization, Principal and Identity objects: -
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