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
In Visual Studio, open or create a SharePoint project.
For more information, see SharePoint Project and Project Item Templates.
In Solution Explorer, choose the project node.
On the menu bar, choose Project, Add New Item.
In the Add New Item dialog box, expand the SharePoint node, and then choose the 2010 item.
In the list of SharePoint templates, choose Application Page.
In the Name box, specify a name for the application page, and then choose the Add button.
Visual Studio adds several folders and files to your project. For more information about these files, see Creating Application Pages for SharePoint.
In the Source view of the Visual Web Developer designer, the ASP.NET page file appears. You can design the page by adding controls from the Toolbox and placing them on content placeholders. For more information, see Source View, Web Page Designer.
If you want to handle control events, add code to the code file for the application page.
The code file appears if you expand the node for the ASP.NET page file and has a .cs or .vb extension, depending on the language of the project. For an end-to-end example of how to create an application page, see Walkthrough: Creating a SharePoint Application Page.