What is the App_Data folder used for in Visual Studio?

Question

App_Data is essentially a storage point for file-based data stores (as opposed to a SQL server database store for example). Some simple sites make use of it for content stored as XML for example, typically where hosting charges for a DB are expensive.

in IIS, highlight the machine, double-click "Request Filtering", open the "Hidden Segments" tab. "App_Data" is listed there as a restricted folder. Yes i know this thread is really old, but this is still applicable.

The intended use of App_data is to store application data for the web process to acess. It should not be viewable by the web and is a place for the web app to store and read data from.

It's a place to put an embedded database, such as Sql Server Express, Access, or SQLite.

The App_Data folder is a folder, which your asp.net worker process has files sytem rights too, but isn't published through the web server.

For example we use it to update a local CSV of a contact us form. If the preferred method of emails fails or any querying of the data source is required, the App_Data files are there.

It's not ideal, but it it's a good fall-back.

From the documentation about ASP.NET Web Project Folder Structure in MSDN:

You can keep your Web project's files in any folder structure that is convenient for your application. To make it easier to work with your application, ASP.NET reserves certain file and folder names that you can use for specific types of content.

App_Data contains application data files including .mdf database files, XML files, and other data store files. The App_Data folder is used by ASP.NET to store an application's local database, such as the database for maintaining membership and role information. For more information, see Introduction to Membership and Understanding Role Management.