So by now you’ve probably heard a little about various .NET 5 announcements and you’re ready to give it a try! I thought first I would give some of the cliffnotes from the .NET 5 announcement, and then jump into how to actually have a play with the preview version of .NET 5 (Correct as of writing this post on 2020-05-22).
- .NET Standard is no more! Because .NET Framework and .NET Core are being merged, there is less of a need for .NET Standard. .NET Standard also covers things like Xamarin but that’s being rolled into .NET 6 (More on that a little later), so again, no need for it.
- .NET Core coincides with C#9 and F#5 releases (As it typically does), but Powershell will now also be released on the same cadence.
- They have added a visual designer for building WinForm applications since you could theoretically build WinForm applications in .NET Core 3.X but not design them with quite as much functionality as you typically would.
- .NET 5 now runs on Windows ARM64.
- While the concept of Single File Publish already exists in .NET Core 3.X, it looks like there has been improvements where it’s actually a true exe instead of a self extracting ZIP. Mostly for reasons around being on read-only media (e.g. A locked down user may not be able to extract that single exe to their temp folder etc).
- More features have been added to System.Text.Json for feature parity with Newtonsoft.Json.
- As mentioned earlier, Xamarin will be integrated with .NET 6 so that there would be a single unifying framework. Also looks like Microsoft will be doing a big push around the .NET ecosystem as a way to build apps once (in Xamarin), and deploy to Windows, Mac, IOS, Android etc. Not sure how likely this actually is but it looks like it’s the end goal.
Setting Up The .NET 5 SDK
So as always, the first thing you need to do is head to the .NET SDK Download page here : https://dotnet.microsoft.com/download/dotnet/5.0. Note that if you go to the actual regular download page of https://dotnet.microsoft.com/download you are only given the option to download .NET Core 3.1 or .NET Framework 4.8 (But there is a tiny little banner above saying where you can download the preview).
Anyway, download the .NET 5 SDK installer for your OS.
After installing, you can run the dotnet info command from a command prompt :
Make sure that you do have the SDK installed correctly. If you don’t see .NET 5 in the list, the most common reason I’ve found is people installing the X86 version on their X64 PC. So make sure you get the correct installer!
Now if you use VS Code, you are all set. For any existing project you have that you want to test out running in .NET 5 (For example a small console app), then all you need to do is open the .csproj file and change :
<PropertyGroup> <OutputType>Exe</OutputType> <TargetFramework>netcoreapp3.1</TargetFramework> </PropertyGroup>
<PropertyGroup> <OutputType>Exe</OutputType> <TargetFramework>net5.0</TargetFramework> </PropertyGroup>
As noted in the cliffnotes above, because there is really only one Framework with no standard going forward, they ditched the whole “netcoreapp” thing and just went with “net”. That means if you want to update any of your .NET Standard libraries, you actually need them to target “net5.0” as well. But hold fire because there is actually no reason to bump the version of a library unless you really need something in .NET 5 (Pretty unlikely!).
.NET 5 In Visual Studio
Now if you’ve updated your .NET Core 3.1 app to .NET 5 and try and build in Visual Studio, you may just get :
The reference assemblies for .NETFramework,Version=v5.0 were not found.
Not great! But all we need to do is update to the latest version and away we go. It’s somewhat lucky that there isn’t a Visual Studio release this year (e.g. There is no Visual Studio 2020), otherwise we would have to download yet another version of VS. So to update, inside Visual Studio, simply go Help -> Check For Updates. The version you want to atleast be on is 16.6 which as of right now, is the latest non-preview version.
Now after installing this update for the first time, for the life of me I couldn’t work out why I could build an existing .NET 5 project, but when I went to create a new project, I didn’t have the option of creating it as .NET 5.
As it turns out, by default the non-preview version of Visual Studio can only see non-preview versions of the SDK. I guess so that you can keep the preview stuff all together. If you are like me and just want to start playing without having to install the Preview version of VS, then you need to go Tools -> Options inside Visual Studio. Then inside the options window under Environment there is an option for “Preview Features”.
Tick this. Restart Visual Studio. And you are away laughing!
Do note that some templates such as Console Applications don’t actually prompt you for the SDK version when creating a new project, they just use the latest SDK available. In this case, your “default” for Visual Studio suddenly becomes a preview .NET Core SDK. Perfectly fine if you’re ready to sit on the edge, but just something to note in case this is a work machine or similar.