How to watch for file changes "dotnet watch" with Visual Studio ASP.NET Core

Question

I am using Visual Studio with ASP.NET Core and run the website using just F5 or Ctrl+F5 (not using the command line directly). I would like to use the "dotnet watch" functionality to make sure all changes are picked up on the fly to avoid starting the server again. It seems that with the command line you would use "dotnet watch run" for this, but Visual Studio uses launchSettings.json and does it behind the scenes if I understand it correctly.

How can I wire up "dotnet watch" there?

Answer 1

Open launchSettings.json and add this to profiles.

  "Watch": {
    "executablePath": "C:\\Program Files\\dotnet\\dotnet.exe",
    "commandLineArgs": "watch run",
    "launchBrowser": true,
    "launchUrl": "http://localhost:5000",
    "environmentVariables": {
      "ASPNETCORE_ENVIRONMENT": "Development"
    }
  }

Open project.json and add this to tools.

"Microsoft.DotNet.Watcher.Tools": "1.0.0-preview2-final"

After restoring, we can Watch from within Visual Studio.

Answer 2

If you want to use ASP.NET 2.x or 3.x you need to change it a bit.

• The watch tool is a global tool now and you don't need to add it as a reference any longer

• The syntax is slightly different

  "Watch": {
    "executablePath": "dotnet.exe",
    "workingDirectory": "$(ProjectDir)",
    "commandLineArgs": "watch run",
    "launchBrowser": true,
    "launchUrl": "http://localhost:5000/",
    "environmentVariables": {
      "ASPNETCORE_ENVIRONMENT": "Development"
    }
  }
  

For .Net 5 & 6

In VisualStudio 2019

1. Go to Tools > ⚙ Options > Projects and Solutions > ASP .NET Core
2. Select Auto build and refresh browser after saving changes in Auto build and refresh option
3. Press Ctrl + F5 (Start Without Debugging) IMPORTANT: Only works if run without debbuging

Otherwise add this to your launchSettings.json:

{
  "iisSettings": {
    ...
  },
  "profiles": {
    ... ,

    "Watch": {
      "commandName": "Executable",
      "executablePath": "dotnet.exe",
      "workingDirectory": "$(ProjectDir)",
      "commandLineArgs": "watch run"
    }

  }
}

The automatically generated profile with "commandName":"Project" has all the other properties needed: launchBrowser, applicationUrl, environmentVariables, dotnetRunMessages and hotReloadProfile. Any modifications should be made there.

Corresponding Blog-Post from Juan Cruz Fiant: https://dev.to/juxant/auto-refresh-with-dotnet-watch-for-asp-net-core-projects-20no

For .Net 8 (with https and app.useHsts)

TLDR;

1. Move the https profile to the top

2. Add "ASPNETCORE_HTTPS_PORT": "7186" to the environment variables section for the https profile

3. Add

   "Watch": {
     "commandName": "Executable",
     "executablePath": "dotnet.exe",
     "workingDirectory": "$(ProjectDir)",
     "commandLineArgs": "watch --non-interactive run",
     "launchBrowser": true,
     "environmentVariables": {
       "ASPNETCORE_ENVIRONMENT": "Development",
       "ASPNETCORE_HTTPS_PORT": "7186"
     },
     "dotnetRunMessages": true,
     "applicationUrl": "https://localhost:7186;http://localhost:5274"
   },
   

---

Things have changed. Visual Studio puts many different Profiles into your launchsettings.json, especially when using https and app.UseHsts.

First I had to move the https profile on top, as the first profile! Under "environmentVariables" I needed to add "ASPNETCORE_HTTPS_PORT": "7186" to make it work with lauchbrowser and the HTTPS redirect.

I added --non-interactive to force watch to restart the app if it can't hot reload and stops asking me.

My complete launchsettings.json

{
  "profiles": {
    "https": {
      "commandName": "Project",
      "launchBrowser": true,
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Development",
        "ASPNETCORE_HTTPS_PORT": "7186"
      },
      "dotnetRunMessages": true,
      "applicationUrl": "https://localhost:7186;http://localhost:5274"
    },
    "http": {
      "commandName": "Project",
      "launchBrowser": true,
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Development",
      },
      "dotnetRunMessages": true,
      "applicationUrl": "http://localhost:5274"
    },
    "IIS Express": {
      "commandName": "IISExpress",
      "launchBrowser": true,
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Development",
      }
    },
    "Watch": {
      "commandName": "Executable",
      "executablePath": "dotnet.exe",
      "workingDirectory": "$(ProjectDir)",
      "commandLineArgs": "watch --non-interactive run",
      "launchBrowser": true,
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Development",
        "ASPNETCORE_HTTPS_PORT": "7186"
      },
      "dotnetRunMessages": true,
      "applicationUrl": "https://localhost:7186;http://localhost:5274"
    },
    "WSL": {
      "commandName": "WSL2",
      "launchBrowser": true,
      "launchUrl": "https://localhost:7186",
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Development",
        "ASPNETCORE_URLS": "https://localhost:7186;http://localhost:5274",
        "ASPNETCORE_HTTPS_PORT": "7186"
      },
      "distributionName": ""
    }
  },
  "$schema": "http://json.schemastore.org/launchsettings.json",
  "iisSettings": {
    "windowsAuthentication": false,
    "anonymousAuthentication": true,
    "iisExpress": {
      "applicationUrl": "http://localhost:60552",
      "sslPort": 44360
    }
  }

If you start watch from the command line, it seems to use the default profile -> the first profile in the list.

If you want to explicitly start the Watch profile from the command-line, use this syntax:

dotnet watch --non-interactive --launch-profile "Watch" --project INSERT_PATH_TO_PROJECT

Answer 3

Just one little correction to @Flynn`s answer. You need to add an

"commandName": "Executable"

argument to the "Watch" profile. Also to define the urls you should define them not in the "Watch" profile, but in the profile with

"commandName": "Program"

argument (it is present in the default launchsettings.json, created by the Visual Studio project templates, so, your launchsettings.json finally looks like this:

"AnyTest.WebClient": {
  "commandName": "Project",
  "launchBrowser": true,
  "environmentVariables": {
    "ASPNETCORE_ENVIRONMENT": "Development"
  },
  "launchUrl": "",
  "applicationUrl": "https://localhost:44353;http://localhost:51895",
  "inspectUri": "{wsProtocol}://{url.hostname}:{url.port}/_framework/debug/ws-proxy?browser={browserInspectUri}"
},
"Watch": {
  "commandName": "Executable",
  "workingDirectory": "$(ProjectDir)",
  "executablePath": "dotnet.exe",
  "commandLineArgs": "watch run"
}

I kept the launchBrowser argument in the Program profile, but browser in not launched. But if this argument is present in the Executable profile, the browser is not launched too and I found no way to launch it automatically.

Answer 4

Open launchSettings.json and add this to profiles.

 "Watch": {
      "executablePath": "dotnet.exe",
      "commandLineArgs": "watch --project ..\\..\\..\\YourProject.csproj run",
      "launchBrowser": true,
      "launchUrl": "http://localhost:5000/",
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Development"
      }
    },

Answer 5

"Watch": {
  "commandName": "Project",
  "launchBrowser": true,
  "launchUrl": "http://localhost:5000/",
  "commandLineArgs": "watch run",
  "workingDirectory": "$(ProjectDir)",
  "executablePath": "dotnet.exe",
  "environmentVariables": {
    "ASPNETCORE_ENVIRONMENT": "Development"
  }
}

This one will work and launch the browser too. It works because of the "commandName": "Project" line, which means it will be launching with the Kestrel server.

Answer 6

In Visual Studio 2019

{
    "profiles": {
        "msteamsimc": {
        "commandName": "Executable",
        "executablePath": "dotnet",
        "commandLineArgs": "watch run",
        "workingDirectory": "$(ProjectDir)",
        "launchBrowser": true,
        "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Development",
        },
        "dotnetRunMessages": "true",
        "applicationUrl": "https://localhost:5001;http://localhost:5000"
    }
    }
}

here an image for confg

here an image for working project 2021-01-11

Answer 7

The accepted answer works, but it's 4+ years old. So here's how you make it work for Visual Studio 2019 (v16.8.5 in my case).

Inside the profiles section of launchSettings.json, you add a new profile, let's say "API Watch", with this content:

"API Watch": {
  "commandName": "Executable",
  "executablePath": "dotnet",
  "commandLineArgs": "watch run",
  "workingDirectory": "$(ProjectDir)",
  "launchBrowser": true,
  "applicationUrl": "https://localhost:5001;http://localhost:5000",
  "environmentVariables": {
    "ASPNETCORE_ENVIRONMENT": "Development"
  },
  "dotnetRunMessages": true
}

And then you go and select it in the Build profiles dropdown:

---

Now when you run it, regardless if with or without Debug mode on, the re-build and browser refresh (I use the Swagger UI as default page) happens automatically.

---

One note about using it in Debug mode, is that Visual Studio will mark the changes with green and will say that they won't be applied until a restart happens. I can confirm that this is not true and that the changes are really reflected by the auto rebuild feature of dotnet watch run. It's just that VS 2019 gets confused and treats things from the old (standard) perspective.

Answer 8

To anyone else reading these really old answers and wondering if it is baked-in yet, then you should read this blog post from Nov 22, 2020.

https://dev.to/juxant/auto-refresh-with-dotnet-watch-for-asp-net-core-projects-20no

Visual Studio 2019 now has a setting for ASP.NET Core to refresh when using IIS Express. By default it is not enabled.

You can still use the launchSettings.json files as described in the article.