Web API in MVC Project isn't hitting breakpoints (“symbols not loaded”)

Question

I have an ASP.NET MVC project, with an ASP.NET web api defined as an area in this project. So the structure is the following:

MVC Web
   Controllers
   View         


        

Answer 1

I had the same issue but mine was related to the addition of a config Transform. Go to Build > Configuration Manager under Active Solution Configuration make sure you have Debug selected.

Answer 2

Possible solution: I had forgotten that I was previously doing some remote debugging and had set debug symbols to be loaded from a UNC path instead of the Microsoft Symbol Servers.

To fix this head to: Tools -> Options -> Debugging -> Symbols -> Make sure 'Microsoft Symbol Servers' is checked.

I also found this issue from creating a new Solution Configuration and not basing it on any existing configuration, such as the DEBUG configuration. That caused Debug Info to be set to none.

To fix this: Right-click your project -> Properties -> Build -> Make sure your faulty Solution Configuration is set -> click Advanced -> change Debug Info to full.

Answer 3

This solved my problem:

• Close\Exit from all instances of IIS Express in the system tray (beside the Windows clock).
• Delete bin and obj folders in your project directory
• Restart Visual Studio
• Run it again

Answer 4

Until you find a permanent solution you can use the method System.Diagnostics.Debugger.Break() to force a break to occur on that line - just like a breakpoint:

public ActionResult IndexCheckInOut(string providerKey, DateTime? date = null)
{
    System.Diagnostics.Debugger.Break();   
    return View("Index");
}

Here are some links to articles that might help you find a more permanent solution:

The breakpoint will not currently be hit

Stepping into ASP.NET MVC source code with Visual Studio debugger

Answer 5

Just had this issue myself and was tearing my hair out for about an hour until I realised Visual Studio had mysteriously switched to run the project in 'Release' mode. Switching back to 'Debug' mode and rebuilding sorted me out.

Probably a very niche answer to this problem, but hopefully this helps somebody.

Answer 6

For me it worked out to just stop IIS and restart Visual Studio. Definitely worth a try before further investigation.