How do I migrate .NET Core 2.2 Web API to .NET Core 3.0?

Question

I was following Microsoft's migration guide, but failed. So, instead, I created a new project with .NET 2.2 to establish a clean template, and then tried migrating to .NET Core 3.0. But it once again failed. In the Startup.cs, the dependency injection cannot find the method services.AddMvc().

It seems my code still refers to .NET 2.2 instead of .NET 3.0.

If I run dotnet watch run, I get the following error:

Application startup exception System.InvalidOperationException: Endpoint Routing does not support 'IApplicationBuilder.UseMvc(...)'. To use 'IApplicationBuilder.UseMvc' set 'MvcOptions.EnableEndpointRouting = false' inside 'ConfigureServices(...). at Microsoft.AspNetCore.Builder.MvcApplicationBuilderExtensions.UseMvc(IApplicationBuilder app, Action'1 configureRoutes) at Microsoft.AspNetCore.Builder.MvcApplicationBuilderExtensions.UseMvc(IApplicationBuilder app) at netmig.Startup.Configure(IApplicationBuilder app, IHostingEnvironment env) in E:\testapp\netmig\Startup.cs:line 46 at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor, Boolean wrapExceptions) at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
at Microsoft.AspNetCore.Hosting.ConfigureBuilder.Invoke(Object instance, IApplicationBuilder builder) at Microsoft.AspNetCore.Hosting.ConfigureBuilder.<>c__DisplayClass4_0.b__0(IApplicationBuilder builder) at Microsoft.AspNetCore.Hosting.GenericWebHostBuilder.<>c__DisplayClass13_0.b__2(IApplicationBuilder app) at Microsoft.AspNetCore.Mvc.Filters.MiddlewareFilterBuilderStartupFilter.<>c__DisplayClass0_0.g__MiddlewareFilterBuilder|0(IApplicationBuilder builder) at Microsoft.AspNetCore.HostFilteringStartupFilter.<>c__DisplayClass0_0.b__0(IApplicationBuilder app) at Microsoft.AspNetCore.Hosting.GenericWebHostService.StartAsync(CancellationToken cancellationToken) Unhandled exception. System.InvalidOperationException: Endpoint Routing does not support 'IApplicationBuilder.UseMvc(...)'. To use 'IApplicationBuilder.UseMvc' set 'MvcOptions.EnableEndpointRouting = false' inside 'ConfigureServices(...). at Microsoft.AspNetCore.Builder.MvcApplicationBuilderExtensions.UseMvc(IApplicationBuilder app, Action'1 configureRoutes) at Microsoft.AspNetCore.Builder.MvcApplicationBuilderExtensions.UseMvc(IApplicationBuilder app) at netmig.Startup.Configure(IApplicationBuilder app, IHostingEnvironment env) in E:\testapp\netmig\Startup.cs:line 46 at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor, Boolean wrapExceptions) at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
at Microsoft.AspNetCore.Hosting.ConfigureBuilder.Invoke(Object instance, IApplicationBuilder builder) at Microsoft.AspNetCore.Hosting.ConfigureBuilder.<>c__DisplayClass4_0.b__0(IApplicationBuilder builder) at Microsoft.AspNetCore.Hosting.GenericWebHostBuilder.<>c__DisplayClass13_0.b__2(IApplicationBuilder app) at Microsoft.AspNetCore.Mvc.Filters.MiddlewareFilterBuilderStartupFilter.<>c__DisplayClass0_0.g__MiddlewareFilterBuilder|0(IApplicationBuilder builder) at Microsoft.AspNetCore.HostFilteringStartupFilter.<>c__DisplayClass0_0.b__0(IApplicationBuilder app) at Microsoft.AspNetCore.Hosting.GenericWebHostService.StartAsync(CancellationToken cancellationToken) at Microsoft.Extensions.Hosting.Internal.Host.StartAsync(CancellationToken cancellationToken) at Microsoft.Extensions.Hosting.HostingAbstractionsHostExtensions.RunAsync(IHost host, CancellationToken token) at Microsoft.Extensions.Hosting.HostingAbstractionsHostExtensions.RunAsync(IHost host, CancellationToken token) at Microsoft.Extensions.Hosting.HostingAbstractionsHostExtensions.Run(IHost host) at netmig.Program.Main(String[] args) in E:\testapp\netmig\Program.cs:line 18 watch : Exited with error code -532462766

The full code I am running can be found on GitHub. My .NET info:

dotnet --info .NET Core SDK (reflecting any global.json): Version:
3.0.100 Commit: 04339c3a26

Runtime Environment: OS Name: Windows OS Version: 10.0.18362 OS Platform: Windows RID: win10-x64 Base Path: C:\Program Files\dotnet\sdk\3.0.100\

Host (useful for support): Version: 3.0.0 Commit: 7d57652f33

.NET Core SDKs installed: 2.2.401 [C:\Program Files\dotnet\sdk] 3.0.100 [C:\Program Files\dotnet\sdk]

.NET Core runtimes installed: Microsoft.AspNetCore.All 2.2.6 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.App 2.2.6 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.0.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.NETCore.App 2.2.6 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 3.0.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.WindowsDesktop.App 3.0.0 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

To install additional .NET Core runtimes or SDKs:
https://aka.ms/dotnet-download

The error looks like it relates to middleware configuration. Check this section: docs.microsoft.com/en-us/aspnet/core/migration/… — juunas
When you change version of Net you always have to do a clean build to get code to compiler properly. — jdweng
@jdweng I did dotnet clean before and dotnet restore afterthat. should i uninstall 2.2 to get this work? — nightingale2k1
You can have more than one version of Net Installed. You could have VS2018 with Net Core 2.0 and VS2019 with Net Core 3.0. The problem is the compiler dependencies do not work when Net changes. You cannot have the obj files on a project mixed different versions of Net. If you update to Net Core 3.0 all the obj files need to be compiled with Net Core 3.0. — jdweng

Tony Ngo Tony Ngo · Accepted Answer · 2019-09-26T10:15:54

For v2.2

    public void ConfigureServices(IServiceCollection services)
    {
        services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);
    }

    public void Configure(IApplicationBuilder app, IHostingEnvironment env)
    {
        app.UseMvc();
    }

And for v3

public void ConfigureServices(IServiceCollection services)
        {
            services.AddControllers();
        }

        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            app.UseRouting();

            app.UseAuthorization();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllers();
            });
        }

Also make sure your csproj is target .net core 3.0

  <PropertyGroup>
    <TargetFramework>netcoreapp3.0</TargetFramework>
  </PropertyGroup>

How do I migrate .NET Core 2.2 Web API to .NET Core 3.0?

1 Answers