Debugging Preparation: ASP.NET Web Applications
The ASP.NET Web site template creates a Web Form application. When you create a Web site using this template, Visual Studio creates the default settings for debugging. In the Project Properties dialog box, you can specify whether you want the Web page to be a startup page. When you start debugging an ASP.NET Web Site with these default settings, Visual Studio starts Internet Explorer and attaches the debugger to the ASP.NET worker process (aspnet_wp.exe or w3wp.exe). For more information, see ASP.NET Debugging: System Requirements.
To create a Web Forms application
On the File menu, choose New Web Site.
In the New Web Site dialog box, select ASP.NETWeb Site.
To debug your Web form
Set one or more breakpoints in your functions and event handlers.
For more information, see Breakpoints and Tracepoints.
When a breakpoint is hit, step through code inside the function. Observe the execution of your code until you isolate the problem.
For more information, see Stepping and Debugging Web Applications and Script.
If you want to change the default debug and release configurations created by Visual Studio, you can do so. For more information, see How to: Set Debug and Release Configurations.
To change the default debug configuration
In Solution Explorer, right-click the Web site, and select Property Pages to open the Property Pages dialog box.
Click Start Options.
Set Start Action to the Web page that should be displayed first.
Under Debuggers, make sure ASP.NET debugging is selected.
For more information, see Property Pages Settings for Web Projects.