Upgrading from ASP.NET Core 2.2 to 3.0

asp.net-core upgrade asp.net-core-3.0 .net-core-3.0
Abhi picture Abhi · Sep 30, 2019 · Viewed 16.1k times · Source

I have an ASP.NET Core project with following csproj configuration:

<PropertyGroup>
  <TargetFramework>netcoreapp2.2</TargetFramework>
</PropertyGroup>
<ItemGroup>
  <PackageReference Include="Microsoft.AspNetCore.App" />
</ItemGroup>

I want to upgrade the project to <TargetFramework>netcoreapp3.0</TargetFramework>. Upon doing so, however, I get following warning:

C:\Program Files\dotnet\sdk\3.0.100\Sdks\Microsoft.NET.Sdk\targets\ Microsoft.NET.Sdk.DefaultItems.targets(149,5): warning NETSDK1080: A PackageReference to Microsoft.AspNetCore.App is not necessary when targeting .NET Core 3.0 or higher. If Microsoft.NET.Sdk.Web is used, the shared framework will be referenced automatically. Otherwise, the PackageReference should be replaced with a FrameworkReference.

What precisely is the solution to this? I tried to remove reference to Microsoft.AspNetCore.App, but that does not work. The code does not reference the shared framework.

Also, what does "Otherwise, the PackageReference should be replaced with a FrameworkReference" mean?

Answer

Anduin picture Anduin · Sep 30, 2019

If you are building a web project, please make sure the first line of your project file is:

<Project Sdk="Microsoft.NET.Sdk.Web">

In this case, it is automaticly included framework: Microsoft.AspNetCore.App. You don't have to include it again.

https://docs.microsoft.com/en-us/aspnet/core/migration/22-to-30?view=aspnetcore-3.0&tabs=visual-studio#framework-reference

If you are building a razor library not a web project, please make sure the first line of your project file is:

<Project Sdk="Microsoft.NET.Sdk.Razor">

In this case, your library might dependend on some class in ASP.NET Core. You have to add this:

  <ItemGroup>
     <FrameworkReference Include="Microsoft.AspNetCore.App" />
  </ItemGroup>

Don't forget to add:

    <AddRazorSupportForMvc>true</AddRazorSupportForMvc>

to <PropertyGroup>

If you are not building a razor library nor a web project, typically you don't need Microsoft.AspNetCore.App. If you can really make sure what you are doing and really need it , consider adding:

  <ItemGroup>
     <FrameworkReference Include="Microsoft.AspNetCore.App" />
  </ItemGroup>

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