Could not load type 'Context' from assembly 'Microsoft.AspNetCore.Hosting, Version=3.0.0.0

问题

Where using .netcore 2.2 an upgrade to .netcore 3.0

This is the error that we encounter when running unit test:

"Could not load type 'Context' from assembly 'Microsoft.AspNetCore.Hosting, Version=3.0.0.0"

回答1:

These steps work on our project:

1. Remove old packages

    <PackageReference Include="Microsoft.AspNetCore.Mvc" Version="2.2.0" />
    <PackageReference Include="Microsoft.AspNetCore.Mvc.Cors" Version="2.2.0" />
    <PackageReference Include="Microsoft.AspNetCore.TestHost" Version="2.2.0" />
    <PackageReference Include="Microsoft.Extensions.Configuration" Version="2.2.0" />

2. Install

    Microsoft.AspNetCore.Mvc.Testing 3.0.0-preview7.19365.7

3. Update Startup.cs

    .AddApplicationPart(Assembly.Load("YourProjectControllerNamespace"))

来源：https://stackoverflow.com/questions/57302131/could-not-load-type-context-from-assembly-microsoft-aspnetcore-hosting-versi