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.NET Core Debugger in VS Code

Posted on 16 Nov 2016 in .net, visual studio code, debugger by Greg E.


Using VS Code on the Mac to code up .NET has been a pretty good experience and constantly improving.

One thing that never really seemed to work for me, however, was using the integrated debugger. I knew in theory it worked, saw it work in other demos, but it always failed with some cryptic error or another on my setup.

With the release of .NET Core 1.1 I figured it must be working these days. But, it didn’t.

The Error

I updated the app to 1.1, and attempted to debug the project and got the message:

Failed to start debugger: File bin/Debug/dnxcore50/libhostpolicy.dylib not found

OK, yeah this thing never works. Well, version 1.1 just came out so maybe something’s out of date. I checked for updates to VS Code, but nothing. I did remember reading at some point that all C#-related support had been moved to the extension, and sure enough there was an update available for it. I updated and on reloading watched a lot of impressive looking updates churning in the output window.

It still didn’t work.

After floundering around for a while, with Google searches coming up empty, and Stack Overflow having nothing to say about it, I tried looking in the directory where it was complaining.

Gregs-MBP:Debug grennis$ ls
dnxcore50	netcoreapp1.0	netcoreapp1.1

Hang on… there are output directories here, and VS code is complaining about a file in the ancient dnxcore50 directory! It should of course be using netcoreapp1.1.

I know that VS Code creates a launch.json file when you first attempt to run the debugger which has a bunch of settings in it. I found this file located in the .vscode directory, and indeed, that’s the problem. In the configuration section of the file I see:

"program": "${workspaceRoot}/bin/Debug/dnxcore50/app.dll",

I could just fix that directory name, but chances are there are other old items in here causing issues. Better to delete the file completely and let VS code regenerated it - and that worked. I ended up checking where launch.json is located (in a dir named .vscode) and there was one other file there (tasks.json).

So, I just nuked the entire .vscode directory, relaunched, and the debugger worked flawlessly. It would be nice if VS Code automatically managed this file after generating it, but the fix is simple enough.

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