用ASP创建API控制器错误.. NET Core 5和实体框架核心

Question

当我在ASP上创建带有scaffold的API控制器时，我得到一个错误。. NET Core 5和实体框架核心;提示"参数连接字符串不能为空"。

我在appSettings.json中的连接设置:

{
"Logging": {
"LogLevel": {
"Default": "Information",
"Microsoft": "Warning",
"Microsoft.Hosting.Lifetime": "Information"
}
},
"AllowedHosts": "*",
"connectionStrings": {
"DefaultConnection":"Data Source=DESKTOP-THJSEM4;Initial,Catalog=M_VPSA_V3;Integrated Security=True"
}}

创建

时编译错误Startup类配置:

public void ConfigureServices(IServiceCollection services)
{
services.AddControllers();
services.AddDbContext<M_VPSA_V3Context>(options => options.UseSqlServer(Configuration.GetConnectionString("DefaultConection")));
services.AddSwaggerGen(c =>
{
c.SwaggerDoc("v1", new OpenApiInfo { Title = "API_MOBEXX", Version = "v1" });
});
}

和堆栈跟踪从错误:

找到发电机'控制器'…
正在运行生成器'controller'…
尝试在内存中编译应用程序。

试图找出EntityFramework元数据模型和DbContext:"Boletum">
值不能为空。(参数connectionString)

> StackTrace:
>
> at Microsoft.EntityFrameworkCore.Utilities.Check.NotEmpty(String value, String parameterName)
> at Microsoft.EntityFrameworkCore.SqlServerDbContextOptionsExtensions.UseSqlServer(DbContextOptionsBuilder optionsBuilder, String connectionString, Action`1 sqlServerOptionsAction)  
> at API_MOBEXX.Startup.<ConfigureServices>b__4_0(DbContextOptionsBuilder options)  
> at Microsoft.Extensions.DependencyInjection.EntityFrameworkServiceCollectionExtensions.<>c__DisplayClass1_0`2.<AddDbContext>b__0(IServiceProvider p, DbContextOptionsBuilder b)  
> at Microsoft.Extensions.DependencyInjection.EntityFrameworkServiceCollectionExtensions.CreateDbContextOptions[TContext](IServiceProvider applicationServiceProvider, Action`2 optionsAction)  
> at Microsoft.Extensions.DependencyInjection.EntityFrameworkServiceCollectionExtensions.<>c__DisplayClass17_0`1.<AddCoreServices>b__0(IServiceProvider p)  
> at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitFactory(FactoryCallSite factoryCallSite, RuntimeResolverContext context)  
> at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)  
> at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitCache(ServiceCallSite callSite, RuntimeResolverContext context, ServiceProviderEngineScope serviceProviderEngine, RuntimeResolverLock lockType)
>
> Value cannot be null. (Parameter 'connectionString') 
>    
> at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScopeCache(ServiceCallSite singletonCallSite, RuntimeResolverContext context)  
> at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)  
> at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.Resolve(ServiceCallSite callSite, ServiceProviderEngineScope scope)  
> at Microsoft.Extensions.DependencyInjection.ServiceLookup.DynamicServiceProviderEngine.<>c__DisplayClass1_0.<RealizeService>b__0(ServiceProviderEngineScope scope)  
> at   Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngine.GetService(Type serviceType, ServiceProviderEngineScope serviceProviderEngineScope)  
> at Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngineScope.GetService(Type serviceType)  
> at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService(IServiceProvider provider, Type serviceType)  
> at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService[T](IServiceProvider provider)  
> at Microsoft.Extensions.DependencyInjection.EntityFrameworkServiceCollectionExtensions.<>c__17`1.<AddCoreServices>b__17_1(IServiceProvider p)  
> at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitFactory(FactoryCallSite factoryCallSite, RuntimeResolverContext context)  
> at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)  
> at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitCache(ServiceCallSite callSite, RuntimeResolverContext context, ServiceProviderEngineScope serviceProviderEngine, RuntimeResolverLock lockType)  
> at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScopeCache(ServiceCallSite singletonCallSite, RuntimeResolverContext context)  
> at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)  
> at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitIEnumerable(IEnumerableCallSite enumerableCallSite, RuntimeResolverContext context)  
> at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)  
> at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitCache(ServiceCallSite callSite, RuntimeResolverContext context, ServiceProviderEngineScope serviceProviderEngine, RuntimeResolverLock lockType)  
> at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScopeCache(ServiceCallSite singletonCallSite, RuntimeResolverContext context)  
> at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)  
> at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.Resolve(ServiceCallSite callSite, ServiceProviderEngineScope scope)  
> at Microsoft.Extensions.DependencyInjection.ServiceLookup.DynamicServiceProviderEngine.<>c__DisplayClass1_0.<RealizeService>b__0(ServiceProviderEngineScope scope)  
> at Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngine.GetService(Type serviceType, ServiceProviderEngineScope serviceProviderEngineScope)  
> at Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngineScope.GetService(Type serviceType)  
> at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService(IServiceProvider provider, Type serviceType)  
> at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService[T](IServiceProvider provider)  
> at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetServices[T](IServiceProvider provider)  
> at Microsoft.EntityFrameworkCore.Design.Internal.DbContextOperations.FindContextTypes()  
> at Microsoft.EntityFrameworkCore.Design.Internal.DbContextOperations.FindContextType(String name)  
> at Microsoft.EntityFrameworkCore.Design.Internal.DbContextOperations.CreateContext(String contextType)  
> at Microsoft.EntityFrameworkCore.Design.DbContextActivator.CreateInstance(Type contextType, Assembly startupAssembly, IOperationReportHandler reportHandler, String[] args)  
> at Microsoft.EntityFrameworkCore.Design.DbContextActivator.CreateInstance(Type contextType, Assembly startupAssembly, IOperationReportHandler reportHandler)  
> at Microsoft.VisualStudio.Web.CodeGeneration.EntityFrameworkCore.EntityFrameworkModelProcessor.TryCreateContextUsingAppCode(Type dbContextType, Type startupType)  
> at Microsoft.VisualStudio.Web.CodeGeneration.ActionInvoker.<BuildCommandLine>b__6_0()  
> at Microsoft.Extensions.CommandLineUtils.CommandLineApplication.Execute(String[] args)  
> at Microsoft.VisualStudio.Web.CodeGeneration.ActionInvoker.Execute(String[] args)  
> at Microsoft.VisualStudio.Web.CodeGeneration.CodeGenCommand.Execute(String[] args)

Answer 1

你的appsettings是错误的:

为节connectionString添加's'

"connectionStrings": {
"DefaultConnection":"Data Source=DESKTOP-THJSEM4;Initial,Catalog=M_VPSA_V3;Integrated Security=True"
}}

[编辑]在getconnection方法中使用错误的字符串名称。defaultconnection缺少一个n