Web Forms Designer
Microsoft Visual Web Developer is a designer that allows you to edit the markup, controls, script, and optionally the code for ASP.NET Web pages. The designer is a rapid development solution for creating ASP.NET Web applications that provides different views of your pages and gives you tools such as the Toolbox and Properties window that make it easy to create and edit page elements.
This designer has two views: Design view and Source view. You can switch between the two views using the Design and Source tabs at the bottom of the page you are editing. If you are working with code-behind pages, you can also open the code file as a separate document in the designer by selecting the code file in Solution Explorer, or by right-clicking your Web page and clicking View Code.
Source view gives you a view of your page that shows the markup directly, which includes HTML elements, ASP.NET controls, and client script. If you are working with a single-file page, Source view also shows you the server code for your page.
For more information, see Source View.
Design view displays ASP.NET Web pages, master pages, HTML pages, and user controls using a near-WYSIWYG view. Design view allows you to add text and elements and then position and size them and set their properties using special menus or the Properties window.
For more information, see Design View.