c# - 无法注册 IRelationalTypeMappingSource

Question

System.InvalidOperationException: '数据库提供程序试图注册'IRelationalTypeMappingSource' 服务的实现。这不是 Entity Framework 定义的服务，因此必须使用“TryAddProviderSpecificServices”方法注册为特定于提供者的服务。
这是我在 DbContext 中运行页面时的异常(exception)情况。
该网站是 Razor Pages。
网站运行良好，我没有改变任何东西，现在发生了。
这是 .csproj

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

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

  <ItemGroup>
    <PackageReference Include="Microsoft.Bcl.AsyncInterfaces" Version="1.0.0" />
    <PackageReference Include="Microsoft.EntityFrameworkCore" Version="5.0.0" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="3.1.10" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.Tools" Version="3.1.10">
      <PrivateAssets>all</PrivateAssets>
      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
    </PackageReference>
    <PackageReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Design" Version="3.1.4" />
    <PackageReference Include="Microsoft.Windows.Compatibility" Version="5.0.0" />
  </ItemGroup>

</Project>

有谁知道如何解决这个问题？

Answer 1

您正在混合版本，并引用过多的包。改成这样:

<ItemGroup>
    <PackageReference Include="Microsoft.Bcl.AsyncInterfaces" Version="1.0.0" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="3.1.10" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.Tools" Version="3.1.10">
      <PrivateAssets>all</PrivateAssets>
      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
    </PackageReference>
    <PackageReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Design" Version="3.1.4" />
    <PackageReference Include="Microsoft.Windows.Compatibility" Version="3.1.1" />
  </ItemGroup>