How to: Create an Application Page
You can create an ASP.NET Web page for one or more SharePoint sites. In SharePoint, these pages are called application pages. Unlike a site page, an application page contains code that runs behind the page. For more information, see Creating Application Pages for SharePoint.
To create an application page
Open or create a SharePoint project in Visual Studio. For more information, see SharePoint Project and Project Item Templates.
In Solution Explorer, select the project node.
On the Project menu, click Add New Item.
In the Add New Item dialog box, in the list of SharePoint templates, select Application Page.
Type a name for the application page in the Name box, and then click Add.
Visual Studio adds several folders and files to your project. For more information about these files, see Creating Application Pages for SharePoint
The ASP.NET page file appears in the Source view of the Visual Web Developer designer. You can design the page by dragging controls from the Toolbox onto content placeholders in Source view. For more information, see Source View, Web Page Designer.
To handle control events, add code to the application page code file.
This file appears if you expand the ASP.NET page file node. The application page code file has a .cs or .vb extension depending on the language of the project. For an end-to-end example of creating an application page, see Walkthrough: Creating an Application Page