Question

可以在UWP（Win 10）应用中使用EF7从类库（通过在类库中定义Models＆amp; DbContext）创建数据库吗？

执行Add-Migration命令时，我在程序包管理器控制台中收到以下错误：

PM> Add-Migration CreateDb
System.InvalidOperationException: The property 'Segments' on entity type 'System.Uri' has not been added to the model or ignored.
   at Microsoft.Data.Entity.Metadata.Conventions.Internal.PropertyMappingValidationConvention.Apply(InternalModelBuilder modelBuilder)
   at Microsoft.Data.Entity.Metadata.Conventions.Internal.ConventionDispatcher.OnModelBuilt(InternalModelBuilder modelBuilder)
   at Microsoft.Data.Entity.Metadata.Internal.InternalModelBuilder.Validate()
   at Microsoft.Data.Entity.ModelBuilder.Validate()
   at Microsoft.Data.Entity.Infrastructure.ModelSource.CreateModel(DbContext context, IConventionSetBuilder conventionSetBuilder, IModelValidator validator)
   at Microsoft.Data.Entity.Infrastructure.ModelSource.<>c__DisplayClass8_0.<GetModel>b__0(Type k)
   at System.Collections.Concurrent.ConcurrentDictionary`2.GetOrAdd(TKey key, Func`2 valueFactory)
   at Microsoft.Data.Entity.Infrastructure.ModelSource.GetModel(DbContext context, IConventionSetBuilder conventionSetBuilder, IModelValidator validator)
   at Microsoft.Data.Entity.Internal.DbContextServices.CreateModel()
   at Microsoft.Data.Entity.Internal.LazyRef`1.get_Value()
   at Microsoft.Data.Entity.Internal.DbContextServices.get_Model()
   at Microsoft.Extensions.DependencyInjection.EntityFrameworkServiceCollectionExtensions.<>c.<AddEntityFramework>b__0_5(IServiceProvider p)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.FactoryService.Invoke(ServiceProvider provider)
   at Microsoft.Extensions.DependencyInjection.ServiceProvider.ScopedCallSite.Invoke(ServiceProvider provider)
   at Microsoft.Extensions.DependencyInjection.ServiceProvider.<>c__DisplayClass12_0.<RealizeService>b__0(ServiceProvider provider)
   at Microsoft.Extensions.DependencyInjection.ServiceProvider.GetService(Type serviceType)
   at Microsoft.Extensions.DependencyInjection.ServiceProviderExtensions.GetService[T](IServiceProvider provider)
   at Microsoft.Data.Entity.Design.Internal.DesignTimeServicesBuilder.<>c__DisplayClass7_0.<ConfigureContextServices>b__8(IServiceProvider _)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.FactoryService.Invoke(ServiceProvider provider)
   at Microsoft.Extensions.DependencyInjection.ServiceProvider.TransientCallSite.Invoke(ServiceProvider provider)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.ConstructorCallSite.Invoke(ServiceProvider provider)
   at Microsoft.Extensions.DependencyInjection.ServiceProvider.TransientCallSite.Invoke(ServiceProvider provider)
   at Microsoft.Extensions.DependencyInjection.ServiceProvider.<>c__DisplayClass12_0.<RealizeService>b__0(ServiceProvider provider)
   at Microsoft.Extensions.DependencyInjection.ServiceProvider.GetService(Type serviceType)
   at Microsoft.Extensions.DependencyInjection.ServiceProviderExtensions.GetRequiredService(IServiceProvider provider, Type serviceType)
   at Microsoft.Extensions.DependencyInjection.ServiceProviderExtensions.GetRequiredService[T](IServiceProvider provider)
   at Microsoft.Data.Entity.Design.MigrationsOperations.AddMigration(String name, String outputDir, String contextType)
   at Microsoft.Data.Entity.Design.OperationExecutor.<AddMigrationImpl>d__7.MoveNext()
   at System.Linq.Buffer`1..ctor(IEnumerable`1 source)
   at System.Linq.Enumerable.ToArray[TSource](IEnumerable`1 source)
   at Microsoft.Data.Entity.Design.OperationExecutor.OperationBase.<>c__DisplayClass4_0`1.<Execute>b__0()
   at Microsoft.Data.Entity.Design.OperationExecutor.OperationBase.Execute(Action action)
The property 'Segments' on entity type 'System.Uri' has not been added to the model or ignored.

有没有人尝试过成功从类库中创建数据库？

Answer 1

使用库中的EF步骤：

1. Add `EntityFramework.Sqlite` NuGet package in library
2. Define Model & ViewModels in library
3. Add reference to library in startup project
4. Add `EntityFramework.Commands` NuGet package in startup project
5. Run `Add-Migration` command in library

使用EF7从类库创建数据库

1 个答案: