.Net Foundation On .NET, 23 Mar 2018

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From YouTube: Dustin Campbell - C# Support in Visual Studio Code

Description

Visual Studio Code offers a great, lightweight editing experience for developers across platforms. There's a community of folks in and outside of Microsoft that working to make sure that C# developers also have a great experience there as well.

In this episode, Dustin Campbell (@dcampbell) joins Rich to talk about the C# extension for Visual Studio Code.
00:45 - How do Visual Studio Code, Omnisharp and C# fit together?
03:10 - How does Visual Studio Code interact with Omnisharp server?
05:36 - Demo - Working with a new .NET Core project
11:56 - Demo - Working to multiple projects
15:31 - Demo - Running unit tests
18:38 - When does support for new C# versions arrive?
20:05 - Does the extension work with preview version of .NET Core?
21:24 - How to install the extension?

Take a look at the following links if you want to learn more:

Omnisharp: http://www.omnisharp.net
Omnisharp on GitHub: https://github.com/OmniSharp/omnisharp-roslyn
Visual Studio Code: https://code.visualstudio.com/
Roslyn GitHub repo: https://github.com/dotnet/roslyn
Working with C# in Visual Studio Code: https://code.visualstudio.com/Docs/languages/csharp?WT.mc_id=ondotnet-channel9-cephilli
VS Code on GitHub - https://github.com/OmniSharp/omnisharp-vscode

A

Hi., this is another episode of the on. net show.

A

And today, we're going to be talking about vs code and omnisharp and c# support in vs code.

A

We've got dustin campbell, who's developer on our team. yes., so dustin,. What do you do for us??

A

I actually do a lot of things.

B

I like to dabble in metal and various things.

B

I work with the omnisharp community.

B

I work on c# for visual studio code and generally, cross platform, tooling experiences,, tooling experiences in visual studio..

B

I also work with the c# lines: design, team.

B

I'm a member of that team and the v.b. line design team., I'm involved in a lot of spaces,.

B

That language, tooling space.

A

Makes sense. yes. so, how about we start.? We've got vs code,, omnisharp, c#.

A

How do these things work, together?,.

A

So, vs code is.

B

A excellent platform for building.

B

Up your own tool chain of things you wanted,.

B

Having an editor experience that allows you to bring in all sorts of different kinds of tools, use, different languages. so,, it's got a really great extension platform, and so as part of the initial release of visuals studio, code,.

B

We built as microsoft, we built a c# extension for visual studio, code,.

B

That really tries to provide that core inner loop experience, a really high fidelity core inner loop experience..

B

What I mean by that is, like you want intellisense,, you want some refactoring,, you want final references and those sorts of core editing, features.

B

And so we build that in c# for visual studio code,, but in order to do that, we needed some way, to have something on the side that actually did the language processing.

B

see, visual studio code is all written on top of node.js and when you write an extension,, you write in typescript,, which is great,, but it's not great. For writing.- I don't want to write a whole new manage compiler or any of that kind of thing for c#. that might take a while. in typescript,, so we have roslyn,.

B

We have the c# compiler and all of the features and different layers of that entire api set that we can use to build a language experience.

B

And so we partnered up with the omnisharp community.

B

Omnisharp is an open source project, that's driven by a number of people and had a storied history.

B

Of different folks that have been involved, and there are omnisharp plugins that can use this little language, server. basically, it a little language server that sits on the client and it knows how to load. Projects, load, solutions,, even still load, old.net, core projects,.

B

Get all the references and source files and produce intellisense., so you can query and say, "hey. Give me the intellisense list that would appear here in this document" and they'll say, "oh yeah, here are all the items that would show up and here's what they are." and there are plugins for that for vim and imax,. They are pretty popular..

B

We use it in c# for visual studio, code,.

B

And it's just a popular extension., there's a lot of people involved and working on that..

B

We have a few people here at microsoft that are working on that as well.

B

right.. So when.

A

I'm in visual studio code and basically, I've got some variable. That's got some object in it,.

A

And I go to press dot, right?

A

and as a user, I'm expecting the set of.

A

Methods or properties or fields that are available on that.

A

from the point of the omnisharp plugin in vs code,.

A

Which you said was written in typescript,. How much does it know at the point of that dot?.

A

Does it not have any semantic knowledge of that?.

B

It has no idea what it is. any sort of that, those bits of information,.

B

They come from omnisharp, the omnisharp server.. They are on the desktop.

A

Right, and so what's the context that the client,.

A

Which is the omnisharp plugging into visual studio, code,.

A

Sends to the omnisharp server.

B

Well, first, when the extension comes up and you've loaded on to a particular workspace,, a visual studio code workspace,, which is basically just a folder, right., it goes and it says, "hey,. Where are all the solutions?? What are all the projects?" and omnisharp initializes itself and loads? All those up.?

B

So then, when you press dot later on,, we basically say, "center requesting" at this file,.

B

At this position,, what would intellisense be,.

B

And that's already loaded up in visual studio, and it's up inside of omnisharp.

A

Right., so it's almost like the opposite of what you would think,, which is the source of truth, is really in the server process.

A

And you're just on the client in the editor.

A

Certainly, you own the ability to edit that document, but.

A

You're effectively just navigating the server view. is that fair?.

B

I mean, yes. everything lives inside the omnisharp piece within an api layer from roslyn called a workspace,, right?

B

right. and it's an overused term, there's. Clearly a workspace,. I just mention a visual studio, code,.

A

Which represents a root folder.

B

Which is a different thing., a workspace as we saw them in roslyn,, the api, that is just basically,. It's the information needed to basically to populate the language server..

B

So that's references, and files, and source files.

B

Those sort of things. the things you would pass to a csharp compiler to get it to compile at the end., we're basically doing all of those processes that a compiler does inside of there..

B

It's just. We stopped short of a mid of actually admitting it to disk.. We just have all of that, all that symbol. Information is already there loaded with in roslyn inside of omnisharp.

A

It makes sense. so how about we look at a very simple sample., so I'm going to use dinacore.

B

As you know, I use that a lot.

A

I do know that.

B

Yes,, you do know that., I'm just going to create a new console. App.

A

We'll just call it "dustin.", that's adorable. yes,, it is adorable., so we're going to go into that "dustin" directory.

A

and then what I do,- and I think everyone does this, you just type "code.",, which basically means open up. Vs code.

A

on this folder, yes? on this folder and we've got some stuff here.

A

So, we're going to get rid of this welcome page.

A

A

So we have this dialogue that came up,, which says "required assets to build and debug are missing from 'dustin'.".

A

That is adorable..

A

That was definitely not planned..

A

Should I press "not now", or should I press "yes"??

A

I would say, go ahead and press "yes".

B

Okay. and what's that's going to do is, it's going to generate the files needed in visual studio code to set up, and remember,, because visual studio code is all about lots of languages, lots of different sorts of experiences to.

B

Building here and support for different things,, and so they have a whole system for defining tasks,, build tasks or test tasks,. You know how to debug., and so that generates those files from your project, for you automatically in c# to be ready to go.

A

I think this line here is the key line in this file.

A

Basically, it says, "build is going to generate the program here.", and this is kind of where you'll find it in order to launch it and debug with it, right?.

B

And even to get that information, it went out to omnisharp to be able to say okay, what is the output path of this actual project?, because it's omnisharp run and it's build internally as a what we call design time building,.

B

We don't actually compile to get some of that information to populate these fields.

A

So,, you would be stuck kind of typing yourself,.

B

But I'm sure because there's a lot of value, here.

A

Right., I don't know if this a problem so much anymore,.

A

But maybe like sometime in.

A

The past, I would do this and depending which order I did it., and sometimes these fields wouldn't be correctly set like this one for example.

B

A

The target framework and I'd have to type that manually.

B

Yeah. there's some issues, there. yeah. does that still occur or?, I don't think it occurs. okay. so,. One of the things about our experience in c# and visual studio code is that we try to be this,.

B

I was talking about earlier with this.. We try to be this experience that kind of gets all the information, all the pieces. It needs to build the language experience kind of on the side.

B

right? so,, of whatever it installed. Near.

B

so,. We don't include all the guts of visual studio to do this instead.

B

if we're on a box that has visual studio or even the visual studio, build tools,, we'll try and use the msbuild from there in order to process these projects to get the information out that we need to populate around some workspace.

B

on your box. It's probably using,.

B

We have a standalone version,, it's really bare bones. and then what it does is it says,? Oh well,, let me try and get the information from the.net core sdk that this project uses., maybe you've, got a global json,. There's.

A

A default of the machine and will kind of align itself.

B

With that and use kind of the msbuild kind of bits from there., if you're running the mono mdk on your machine,.

B

It'll, try and grab it from there a more recent version than you can actually use it to edit android and ios apps. and all is good. so,. It always tries to use whatever is around it to get the most,.

B

I guess, best language, experience.

B

so,. In this case, it's going to grab it from your.net core sdk., because it's on the side, sometimes,.

B

It might not do the best job.

B

and you should email me when that happens..

B

I will dig in and find find the problem.

B

so,, because sometimes that's what happens. right? so,. I didn't find this bit of information. It couldn't run msbuild properly,, so the up with path it gave. You was a best guess.

A

I guess also part of it is omnisharp in vs code clearly needs some additional software to run.

B

And because you try and grab.

A

The software that's available,, it presumably means; a). You can start delivering an experience quicker and.

A

B), you don't have to download as much stuff to the machine on the user's behalf. all right.

B

Actually go to the "view menu", if you don't mind and bring up the "output" yeah.

B

A

"Output" right there after that.

B

And so, if you click where it says, "tasks" in that little drop down there, you'll find the "omnisharp log"..

B

That shows you what was going on to actually load this thing up, where it found kind of the various bits on the machine.

B

If you scroll up you'll, find actually that here are the instances of the msbuild that are found in the machine. so,, it's actually running a mono right, now., okay. cool., but mono also supports the.net core sdk and that's pulling that through and letting.

B

so,. It's using the msbuild for mono.

A

Very nice., so, okay. that makes a ton of sense.

A

Okay. so,, I think now, let's just do a couple of things before we get to something more complicated., okay. so,. Here we are already getting a total sense and we can type.

B

That works. yeah type another writeline.

A

And one of things I found super interesting and valuable.

A

So,, I think everyone likes interpolated strings.

A

and when I first started using this,, I guess I'm going to create a variable, here.

A

sure.. You could see. I'm super inventive.

B

A

Yeah. and so I thought. pm, code. yeah. its very much pm code.

A

And I thought this part is probably not going to work,.

B

But this actually does work.

A

Yeah. absolutely., that does nothing because there's nothing.

B

You understand the context.

A

Yeah., that's there's also that.

A

so, this works and then the program is going to run, and so I can actually set. Let's actually show this part. yeah. save it, and then we go here.

A

And this is where I put debug and everything works.

B

Right. so, one of the things we've done with c# for visual studio code. We actually use the visual studio debugger in here and then debugger team is engaged in working on this along with us, and is checked in all the code to make sure that we have a great debugging, experience.

B

and they're continually trying to improve it and tweak it,. But you can see up there in your local's window. You've got the args showing up and all that sort of thing.

B

It's surprisingly good.

B

A

That was really well done.. I've used it a lot., yeah. okay.. So let's go beyond this trivial example.

A

sure. and I want it so much with this closer.

A

The thing with this kind of where it's a little different than visual studio., if I don't really have the right workspace,.

A

What I like to do is I just go to the right. Workspace.

A

I just opened up vs code again. yeah, you're, crazy?,.

B

Yeah. you can do that. okay., so this is,, I will pimp a little bit..

B

I will push the visual studio code.

B

Multi workspaces that they added,, so that you can have workspaces where you don't have to.

B

Go to the top of some cone of a giant bunch of folders.

B

You can pick the folders that you want to put into a visual studio code. Workspace., that's really,, really nice.

A

Makes sense. yeah. so do we do here? so, here we actually have three samples that are in this. Actually, four, it would seem here.

A

And how do I switch?

A

like so I want to work on this. One.

A

looks like it's already: working.

A

it does. okay. so,. This one is already working.

B

There are cases where you can get into where you have multiple projects and you want to be able to switch between them though.

B

and that's what this fire guy is. so down at the bottom right.. This is something that's it's not as discoverable as we'd like..

B

It tries to find places where it will.

B

Search through and find all the things that you can add in here that you want to select.

B

so, one of the things that ends up happening. Is, its got some real, weird semantics,. It looks for solution files first.. If it doesn't find solution files,, it just adds folders like the root folder in this case..

B

When omnisharp is loaded on the root folder,, it will just go, find all the c# projects under there and load them all. Up.

A

This is working right, now., it's going.

B

To work for everything, that's in there. if you have a solution file or you have a couple of solution. Files, in that case solution files are kind of like little views on multiple projects., right? and so,, where you want to have one set of projects and another set of projects, and so you can click that fire icon and it will show the different solutions that you can pick..

B

A

And also we had some functionality back in the day,.

B

Back when we had project.json in.net core 1.0.

B

I remember that.

A

We remember those days.

B

And there was logic to go, pick different project, json projects or centralize, it on., but what we did with this was we said,, let's just scavenge,.

B

If there are no solution, files or anything, let's just scavenge the whole thing. find the whole process.

A

Then I have,, let's just make sure I've got the right. Stuff.

A

I've got a better one. Too. oh,! You got a better one to demonstrate. Problems.

B

Yes., let's go here.

A

Just make sure we got the right, stuff. okay., see if this works. yeah., so this one is a bit better.

A

This one has samples.

A

In it- and this actually has solutions.

A

Yeah. so,, I guess, is it fair to say it's still loading, is that what's?

A

well,, let's see. so, some cases what it will try and.

B

Do the extension will try and find solution files to try and load.

B

occasionally,? It won't work out, and so what we'll do is we'll just try opening a c# file..

B

Let's look at the switcher to show up that's what happen.

B

so, it did load the extension,, but it didn't go, hey,. I don't know what to load., and so it dropped that down by the file it says, switch projects,. You can pick the one you want, and you can come in here.

B

and it will remember, when you open up that particular folder again,, that particular workspace,. It will remember the last solution you had open in that workspace. so, the next time you open it,. If you picked one it'll pick that one.

B

and if you need to go to a different one and edit that you can select it down there.

B

and these work across those multi workspaces..

B

So what I was wanting to show here, was,.

A

So this project happens to have some tests.

A

okay. and I'm not actually entirely sure why we're seeing this still. sure.. But I was wanting to show that you can actually run and debug tests.

A

B

Right., I hope it works.. I don't know, with that. Squiggle there,, I'm not feeling really confident about it.

A

Yeah., so they actually did ask me,. Actually I don't think it restored this project for some reason.

B

A

So actually,, I guess, if we do, control tick is it?.

A

I think that's right.

B

Yeah. so,: let's just do.

A

This one manually, because for some reason that didn't work.

B

Sure. and if you do a .net restore,, it's going to omnisharp doesn't, the way we have a c# previous code, it won't automatically restore your projects like you might get in vs., probably because you'll start getting all sorts of problems,, because very often, when you're using visual studio, code, you're using it in tandem with the command line or the terminal window,.

A

And you're constantly doing like,.

B

Get clean or doing a build from the command line,.

B

That can really mess up and ask you to restore a lot.

B

so,. Let's just do a.net restore down there.

A

I guess there's a shot, one file left to do that, one thing. okay., then we'll see.

B

We'll see if it works. it might not work.

B

it might not. I've seen it not work.

A

It would have help if we just maybe switch back and forth.

B

I don't think so. okay. it could or we just need to wait for it to come. Back.

A

Okay. so right now,, it's just.

B

Unloaded itself and it's probably coming back up, and there you go, and we'll see if it actually resolves this.. It looks like it.

B

well, hover over it,, we'll see. that looks pretty good.

B

That looks pretty good.

A

Okay. so, what I do here,, so we can debug it to let's start with running a test.

A

yeah. so,. What this does is it runs this one test. Is that what it did?, yeah.

B

Yeah. in our latest release, I think we added,.

B

In the latest release, the extension might be in beta right. actually didn't make the latest releases in beta right.

A

Now, if you wanted to go grab at some point,.

B

But we added those same annotations on the class level.

B

so,. If you want to run a class of tests.

A

Oh, I super love, that., yeah actually.

A

and then, if we want to debug test, this is actually my favorite.. I have used this. it's good, because this was a lot of work..

A

Yes, I do use this.

A

so,, it's loading, upto, the debugger, and then it's stopped.

A

Within the context of this test, at that breakpoint.

A

yeah. I mean you can do this obviously and. it's a lot of process kind of maneuvering and.

B

Ports open with a debugger to tell it when it's ready to go and all these kinds of things. there's a whole dance under the hood that work that..

B

I'm very pleased that it just worked.

A

Yes. but I've been in the case where.

A

I'm trying to write some tests for this project and, like a bunch of them, are failing.

A

not entirely sure. Why and being able to debug in terms of a test is beyond useful.

B

It's part of the inner loop right?, I mean that's just the core of normal sort of development.. Today I got a test. It's failing,. I need to debug that test and see why its failing., I need to step in and see what's going, on, right?.

A

Okay. so,, I got a couple more closing type questions which is,.

A

When do new, c# versions show up in the sharp?.

A

So, c# language, versions?

A

yes., like 7.2 or 7.3. If we're going to have one of those.

B

They lag a little bit as far as support in c# or vs code,, mostly because the open source project we try and wait for stable versions to show up on nuget.org,, as opposed to going to private, like myget feeds where who knows it's, the wild west right of nightly builds., and so they try and hold to that..

B

Sometimes, though, there are issues that moving forward in language versions.

B

Is usually pretty easy.? Sometimes there can be other things that make it more.

B

Difficult to move forward, msbuild things that change.

B

Sometimes updating omnisharp to the latest and greatest stuff can be tricky.

B

But typically we try and get those language versions as quickly as we can.

B

right now. Actually we have there's a pr up there right, now. we're just trying to figure out why it's not working yet to get the latest roslyn packages that were just shipped in 15.6..

B

Those don't have new language bits yet,, but they have bug fixes to the language that we have.

B

So,, it's useful to get those anyways.

A

Right. so, the goal is that every one time the visual studio experience and the vs code experience should be the same with respect.

B

To msbuild fixes, language, features?.

A

Now, what about.net core., if I have installed.net core.

A

2.1 preview 1 for example, can I use that?.

B

It should work. yeah., I think you are, aren't you. you probably are., I probably, yeah.. What happens with.net core is because we.

B

I am. in fact turns out.

A

But what we do.

B

With.Net core, because we try and be on the side of that we try and say, "okay, what.net core version is my project using?" and we go and load up the bits out of that.net core sdk.

B

Right. and so then we're using those particular.

B

Sometimes there can be differences,, sometimes there going to be problems,, but it works out pretty well most of the time.

A

Right. so,, I could kind of be a bleeding edge developer and want all the latest stuff in vs code with omnisharp should work for me, or, if I'm someone who prefers to be.

A

On pure stable, then it's also a good choice?.

B

We try and be resilient. we've had a number of customers over the years of c# or vs code that are trying to be on the latest and greatest, and they're grabbing our latest things, and they're building core effects themselves: whatever, right?

B

they're on the very latest and greatest.

A

And that's a party.

B

And they have issues and we try and fix those issues,.

B

And try and fix them in such a way that we just remain resilient against that class of problem.

B

A

Yeah. right. so,, I guess in closing you.

A

Should just use vs code?.

B

C#., no, you don't have to spell it. Out. okay. c# like it's supposed to be.

B

and in this particular case it's.

A

The second one just install that,, obviously I would have it installed.

B

Five million.: when did we pass five?? That was fantastic.. That makes me happy. yeah., I'm I on the right version.

A

Here, by the way, I'm on 1.14? 1.14 is the current released version.

A

B

We are at like beta two of 1.15, which you can get from our repo..

B

That's github.com/omnisharp/omnisharp-vscode.,.

B

And we have releases there that can be installed, separately.

A

Right. so that's,, we should just open this and then.

A

yeah. omnisharp. We definitely didn't prepare this.

A

No, no. omnisharp/omnisharp-vscode.

A

I think I'm having stage fright with respect to my fingers.

B

Yeah, you did it, now you're good. yeah, that's it., no stage fright, you feel confident from now on.. If I have troubles, I can file issues here., you can file issues here..

B

If you click on our releases, you'll find the breakdown right. Here.

B

yeah.. I have used github before.. You find that okay, here's the latest betas and the things that we're doing in these. also try and make things constantly. Better.

B

awesome. okay.. Well, thanks for coming by.

A

Absolutely., this was a great look into vs. Code, looks super useful.

B

It is super useful., you know, that,, you use this.

A

It is very useful.

B

It is excellent.

A

It actually has become my number one editor., oh great., for sure. from both the pure text, editor standpoint.

A

And ide standpoint. awesome. awesome. okay. well,. This was another episode of on.net..

A

We looked at omnisharp, and c#, and vs code.

A

and dustin kind of took us through that. thanks for watching.