Now that the flames have simmered down on the Hot Reload Debacle, maybe it’s time again to revisit this feature!
I legitimately feel this is actually one of the best things to be released with .NET in a while. The amount of frustrating times I’ve had to restart my entire application because of one small typo… whereas now it’s Hot Reload to the rescue!
It’s actually a really simple feature so this isn’t going to be too long. You’ll just have to give it a crack and try it out yourself. In short, it looks like this when used :
In case it’s too small, you can click to make it bigger. But in short, I have a console application that is inside a never ending loop. I can change the Console.WriteLine text, and immediately see the results of my change *without* restarting my application. That’s the power of Hot Reload!
And it isn’t just limited to Console Applications. It (should) work with Web Apps, Blazor, WPF applications, really anything you can think of. Obviously there are some limitations. Notably that if you edit your application startup (Or other run-once type code), your application will hot reload, it doesn’t re-run any code blocks, meaning you’ll need to restart your application to get that startup ran again. I’ve also at times had the Hot Reload fail with various errors, usually meaning I just restart and we are away again.
Honestly, one of the biggest things to get used to is the mentality of Hot Reload actually doing something. It’s very hard to “feel” like your changes have been applied. If I’m fixing a bug, and I do a reload and the bug still exists…. It’s hard for me to not stop the application completely and restart just to be sure!
Hot Reload In Visual Studio 2022
Visual Studio 2019 *does* have a hot reload functionality, but it’s less featured (Atleast for me). Thus I’m going to show off Visual Studio 2022 instead!
All we need to do is edit our application while it’s running, then look to our nice little task bar in Visual Studio for the following icon :
That little icon with two fishes swimming after each other (Or.. atleast that’s what it looks like to me) is Hot Reload. Press it, and you are done!
If that’s a little too labour intensive for you, there is even an option to Hot Reload on file save.
If you’re coming from a front end development background you’ll be used to file watchers recompiling your applications based on a save only. On larger projects I’ve found this to maybe be a little bit more pesky (If Hot Reload is having issues, having popups firing off every save is a bit annoying), but on smaller projects I’ve basically run this without a hitch everytime.
Hot Reload From Terminal
Hot Reload from a terminal or command line is just as easy. Simple run the following from your project directory :
dotnet watch
Note *without* typing run after (Just incase you used to use “dotnet watch run”). And that’s it!
Your application will now run with Hot Reload on file save switched on! Doing this you’ll see output looking something like
watch : Files changed: F:\Projects\Core Examples\HotReload\Program.cs~RF1f7ccc54.TMP, F:\Projects\Core Examples\HotReload\Program.cs, F:\Projects\Core Examples\HotReload\qiprgg31.zfd~ watch : Hot reload of changes succeeded.
And then you’re away laughing again!
