.Net Core2.2升级到3.1小记

时间 2019-12-20

标签 core2.2 core 升级 3.1 繁體版

原文原文链接

.NET Core 3.1 做为LTS长期支持版本，会提供3年的支持(明年就出.net5)，值得升级(吗)。web

目前主流的第三方包大多都已经提供了支持，2.x => 3.1仍是变化不是特别多，EF Core坑就大咯，谨慎。app

ASP.NET Core 3.1 的新增功能框架

https://docs.microsoft.com/zh-cn/aspnet/core/release-notes/aspnetcore-3.1?view=aspnetcore-3.1ide

EF Core 3.0重大改变ui

https://docs.microsoft.com/zh-cn/ef/core/what-is-new/ef-core-3.0/breaking-changesspa

1，将VS2019更新到16.4.x，会自动安装3.1的SDK。.net

2，将项目目标框架升级到3.1，右键项目 - 属性 - 目标框架，或者修改csproj文件。code

  <PropertyGroup>
    <TargetFramework>netcoreapp3.1</TargetFramework>
  </PropertyGroup>

3，WEB项目中Program.cs文件，WebHost 改成 Hostblog

public class Program
{
    public static void Main(string[] args)
    {
        CreateHostBuilder(args).Build().Run();
    }

    public static IHostBuilder CreateHostBuilder(string[] args) =>
        Host.CreateDefaultBuilder(args)
            .ConfigureWebHostDefaults(webBuilder =>
            {
                webBuilder.UseStartup<Startup>();
            });
}

4，WEB项目中Startup.csget

ConfigureServices 方法中 services.AddMvc() 改成 services.AddControllersWithViews()

//services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);
services.AddControllersWithViews();

Configure 方法中 app.UseMvc() 改成 app.UseRouting() 与 app.UseEndpoints()

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    if (env.IsDevelopment())
    {
        app.UseDeveloperExceptionPage();
    }
    else
    {
        app.UseExceptionHandler("/Home/Error");
    }
    app.UseStaticFiles();
    app.UseAuthorization();

    app.UseRouting(); app.UseEndpoints(endpoints =>
    {
        endpoints.MapControllerRoute(
            name: "default",
            pattern: "{controller=Home}/{action=Index}/{id?}"); });
}

5，更新全部(相关)nuget包到最新

6，从新生成解决方案，报错 The project .... must provide a value for Configuration.

从 Web 项目中移除 Microsoft.AspNetCore... 的 PackageReference，由于已经包含在3.1的目标框架内了。

<PackageReference Include="Microsoft.AspNetCore.App" />
<PackageReference Include="Microsoft.AspNetCore.Razor.Design" Version="2.2.0" PrivateAssets="All" />

大功告成，至少编译经过了，运行中目前只碰到一个坑。

A tracking query projects owned entity without corresponding owner in result.Owned entities cannot be tracked without their owner. Either include the owner entity in the result or make query non-tracking using AsNoTracking().

AutoMapper的ProjectTo<>致使，暂时加了个AsNoTracking()解决问题，根据报错信息来看还有另外一种解决方案。

public IEnumerable<UserDto> GetAll()
{
    return _userRepository.GetAll(tracking: false)
        .OrderByDescending(s => s.Id)
        .ProjectTo<UserDto>(_mapper.ConfigurationProvider)
        .AsEnumerable();
}