In case you are ever in a situation where you need to debug code triggered in the ASP.Net Application_Start event before you have time to attach a debugger and your website can’t run by simply starting it in Visual Studio using Run/F5, you can do so by using ‘Restart’ on the website instead of recycling the app pool the website uses in IIS.
Issue:
You set a breakpoint in Application_Start, but the breakpoint never gets hit.
Reason:
When you are debugging your ASP.NET website in IIS, the Application_Start event fires before the Visual Studio debugger has a chance to attach to the IIS process.
Solution:
- Set your breakpoint in Application_Start
- Start the Visual Studio debugger (F5) or manually attach the process (in the menu select Debug > Attach to process)
- (If running via pressing ‘F5′) Wait for the Visual Studio debugger to open your website in the default web browser (this signifies it has attached to the IIS process).
- Open IIS Manager.
- Select your website (left pane). If you are debugging an application hosted by a parent website, select the parent website.
- Click the [Restart] button.
- Switch back to the web browser and refresh your website (F5).
- The Visual Studio debugger will now hit the breakpoint you set in Application_Start.