If you are attaching to asp.net worker process, then kill the process, start up the website and reattach the debugger.
If you are using the built in web server, then make sure you stop the project and the WebDev.WebServer.Exe associated with it.
If all else fails, right click on the breakpoint and choose locations. Then enable the "allow code to be different..." check box at the bottom.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…