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系统.TypeLoadException：无法加载类型“Microsoft.EntityFrameworkCore.Infrastructure.DesignTimeProviderServicesAttribute”。

.net-coreentity-framework-core.net-core-3.1ef-core-3.1
3

我使用 .net core 3.1 更新了现有数据库的模型。

尝试在包管理器控制台中使用以下命令添加实体：

dotnet ef dbcontext scaffold "Server=xxxxxxxx;Database=Test;Trusted_Connection=True;" Microsoft.EntityFrameworkCore.SqlServer --output-dir UserEntity --table users

遇到以下异常：

Build started...
Build succeeded.
System.TypeLoadException: Could not load type 'Microsoft.EntityFrameworkCore.Infrastructure.DesignTimeProviderServicesAttribute' from assembly 'Microsoft.EntityFrameworkCore, Version=3.1.6.0, Culture=neutral, PublicKeyToken=adb9793829ddae60'.
   at System.ModuleHandle.ResolveTypeHandleInternal(RuntimeModule module, Int32 typeToken, RuntimeTypeHandle[] typeInstantiationContext, RuntimeTypeHandle[] methodInstantiationContext)
   at System.Reflection.RuntimeModule.ResolveType(Int32 metadataToken, Type[] genericTypeArguments, Type[] genericMethodArguments)
   at System.Reflection.CustomAttribute.FilterCustomAttributeRecord(MetadataToken caCtorToken, MetadataImport& scope, RuntimeModule decoratedModule, MetadataToken decoratedToken, RuntimeType attributeFilterType, Boolean mustBeInheritable, ListBuilder`1& derivedAttributes, RuntimeType& attributeType, IRuntimeMethodInfo& ctor, Boolean& ctorHasParameters, Boolean& isVarArg)
   at System.Reflection.CustomAttribute.AddCustomAttributes(ListBuilder`1& attributes, RuntimeModule decoratedModule, Int32 decoratedMetadataToken, RuntimeType attributeFilterType, Boolean mustBeInheritable, ListBuilder`1 derivedAttributes)
   at System.Reflection.CustomAttribute.GetCustomAttributes(RuntimeModule decoratedModule, Int32 decoratedMetadataToken, Int32 pcaCount, RuntimeType attributeFilterType)
   at System.Reflection.CustomAttribute.GetCustomAttributes(RuntimeAssembly assembly, RuntimeType caType)
   at System.Reflection.RuntimeAssembly.GetCustomAttributes(Type attributeType, Boolean inherit)
   at System.Attribute.GetCustomAttributes(Assembly element, Type attributeType, Boolean inherit)
   at System.Attribute.GetCustomAttribute(Assembly element, Type attributeType, Boolean inherit)
   at System.Reflection.CustomAttributeExtensions.GetCustomAttribute[T](Assembly element)
   at Microsoft.EntityFrameworkCore.Design.Internal.DesignTimeServicesBuilder.ConfigureProviderServices(String provider, IServiceCollection services, Boolean throwOnError)
   at Microsoft.EntityFrameworkCore.Design.Internal.DesignTimeServicesBuilder.Build(String provider)
   at Microsoft.EntityFrameworkCore.Design.Internal.DatabaseOperations.ScaffoldContext(String provider, String connectionString, String outputDir, String outputContextDir, String dbContextClassName, IEnumerable`1 schemas, IEnumerable`1 tables, Boolean useDataAnnotations, Boolean overwriteFiles, Boolean useDatabaseNames)
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.ScaffoldContextImpl(String provider, String connectionString, String outputDir, String outputDbContextDir, String dbContextClassName, IEnumerable`1 schemaFilters, IEnumerable`1 tableFilters, Boolean useDataAnnotations, Boolean overwriteFiles, Boolean useDatabaseNames)
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.ScaffoldContext.<>c__DisplayClass0_0.<.ctor>b__0()
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.<>c__DisplayClass3_0`1.<Execute>b__0()
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.Execute(Action action)
Could not load type 'Microsoft.EntityFrameworkCore.Infrastructure.DesignTimeProviderServicesAttribute' from assembly 'Microsoft.EntityFrameworkCore, Version=3.1.6.0, Culture=neutral, PublicKeyToken=adb9793829ddae60'.

注意：

使用以下版本的实体框架:

  1. Microsoft.EntityFrameworkCore.Design - 3.1.6
  2. Microsoft.EntityFrameworkCore.SqlServer - 1.1.6

请问有人能帮我解决这个问题吗？

提前感谢。

1个回答
1

为什么您使用的是较旧版本的 Microsoft.EntityFrameworkCore.SqlServer？尝试将其更新到 Microsoft.EntityFrameworkCore.SqlServer 3.1.6。

当我搜索错误时，发现 DesignTimeProviderServicesAttribute 只支持 Entity Framework Core 1.1 版本，该版本位于 Microsoft.EntityFrameworkCore.Infrastructure 下。

由于您正在使用更新的版本，Microsoft.EntityFrameworkCore.Infrastructure 不包括 DesignTimeProviderServicesAttribute。请在 MSDN 上验证相同的信息，链接如下：

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