问题
What is the point of having App_code & App_data folders?
Why doesn't my objectDataSource detect classes unless files are in App_Code?
Please provide as much detail as you can, I'm new to ASP.Net
回答1:
These folders have special purpose. From this article - ASP.NET Web project folder structure.
App_Code
App_Code contains source code for shared classes and business objects (for example, ..cs, and .vb files) that you want to compile as part of your application. In a dynamically compiled Web site project, ASP.NET compiles the code in the App_Code folder on the initial request to your application. Items in this folder are then recompiled when any changes are detected.
Note : You can add any type of class file to the App_Code folder in order to create strongly typed objects that represent those classes. For example, if you put Web service files (.wsdl and .xsd files) in the App_Code folder, ASP.NET creates strongly typed proxies for those classes.
Code in the App_Code folder is referenced automatically in your application. The App_Code folder can contain sub-directories of files, which can include class files that in different programming languages.
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.
回答2:
To sum it up :
- IIS will NEVER serve any file located in those folders (the same way it will not ever serve the Web.config file)
- files in the
App_Codefolder will automatically be recompiled when a change occurs in the code.
回答3:
They're mainly used with the Website template. Use the ASP.NET project template instead and avoid using these folders, especially if you are creating libraries or user controls.
http://www.codersbarn.com/post/2008/06/01/ASPNET-Web-Site-versus-Web-Application-Project.aspx
来源：https://stackoverflow.com/questions/7480437/asp-net-app-data-app-code-folders