未找到方法：'System.Object Microsoft.EntityFrameworkCore.Infrastructure.IAnnotatable.get_Item(System.String)'

Question

我正在使用 C#，我想 Add-Migration InitialVersion 但有一个问题：

Method not found: 'System.Object Microsoft.EntityFrameworkCore.Infrastructure.IAnnotatable.get_Item(System.String)'

我使用的Nuget包：

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

 <PropertyGroup>
   <TargetFramework>net5.0</TargetFramework>
 </PropertyGroup>

 <ItemGroup>
   <PackageReference Include="Microsoft.EntityFrameworkCore" Version="6.0.0-preview.2.21154.2" />
   <PackageReference Include="Microsoft.EntityFrameworkCore.Tools" Version="6.0.0-preview.2.21154.2">
     <PrivateAssets>all</PrivateAssets>
     <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
   </PackageReference>
   <PackageReference Include="Pomelo.EntityFrameworkCore.MySql" Version="5.0.0-alpha.2" />
 </ItemGroup>

</Project>

Answer 1

将 Microsoft.EntityFrameworkCore 和 Microsoft.EntityFrameworkCore.Tools 降级到最新的 5th 版本。您可以使用下一个命令通过 dotnet CLI 执行此操作：

dotnet add package Microsoft.EntityFrameworkCore --version 5.0.4
dotnet add package Microsoft.EntityFrameworkCore.Tools --version 5.0.4

Indexer accepting string was removed from IAnnotatable in the 6th preview version.

Answer 2

另一种选择是将 dotnet-ef 更新为与您的项目中相同的版本

dotnet tool update --global dotnet-ef --version 6.0.0-preview.2.21154.2

未找到方法：'System.Object Microsoft.EntityFrameworkCore.Infrastructure.IAnnotatable.get_Item(System.String)'

Method not found: 'System.Object Microsoft.EntityFrameworkCore.Infrastructure.IAnnotatable.get_Item(System.String)'

.net

c#

mysql

entity-framework

pomelo-entityframeworkcore-mysql