[英]How to use more than one DBContext in a controller
如何在 controller 中使用多個 DBContext,我試圖以不同的方式重載 construktors?
一些 Controller:
public C1(DBContext1 a, DBContext2 b, DBContext3 c)
{
}
//public C1(DBContext1 a)
//{
//}
//public C1(DBContext2 b)
//{
//}
//public C1(DBContext3 c)
//{
//}
啟動.cs:
services.AddDbContext<DBContext1>(options =>
options.UseSqlServer(new string(K.ConnectionString))
);
services.AddDbContext<DBContext2>(options =>
options.UseSqlServer(new string(K.ConnectionString))
);
services.AddDbContext<DBContext3>(options =>
options.UseSqlServer(new string(K.ConnectionString))
);
我找到了這個,但它似乎已經過時了
錯誤(,當前端調用構造函數時):
執行請求時發生未處理的異常。
異常:System.InvalidOperationException:傳遞給 DBContext1 構造函數的 DbContextOptions 必須是 DbContextOptions。 注冊多個 DbContext 類型時,請確保每個上下文類型的構造函數都具有 DbContextOptions 參數,而不是非泛型 DbContextOptions 參數。 在 Microsoft.EntityFrameworkCore.DbContext..ctor(DbContextOptions options) at _4_DWH.DBContext1..ctor(DbContextOptions options) 在 D:...\DBContext1.cs:line 43 at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments,簽名 sig,Boolean 構造函數,Boolean wrapExceptions) 在 System.Reflection.RuntimeCultureConstructorInfo.Invoke,Object[BindingFlag]
在 Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, RuntimeResolverContext context) 在 Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor2.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 參數)在 Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.Resolve(ServiceCallSite callSite, ServiceProviderEngineScope scope) 在 Mic rosoft.Extensions.DependencyInjection.ServiceLookup.DynamicServiceProviderEngine.<>c__DisplayClass1_0.b__0(ServiceProviderEngineScope 范圍)在 Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngine.GetService(類型 serviceType,ServiceProviderEngineScope serviceProviderEngineScope)
在 Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngineScope.GetService(類型 serviceType) 在 Microsoft.Extensions.DependencyInjection.ActivatorUtilities.GetService(IServiceProvider sp,類型類型,類型 requiredBy,Boolean isDefaultParameterRequired)
在 lambda_method(Closure, IServiceProvider, Object[] ) 在 Microsoft.AspNetCore.Mvc.Controllers.ControllerActivatorProvider.<>c__DisplayClass4_0.b__0(ControllerContext controllerContext) 在 Microsoft.AspNetCore.Mvc.Controllers.ControllerFactoryProvider.<>c__DisplayClass5_0.g__CreateController|0( ControllerContext controllerContext) at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted) at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeInnerFilterAsync() --- End of stack trace from previous location where exception was thrown --- at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Awaited|24_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Z27226C 864BAC7454A8504F8EDB15D95BZ isCompleted) at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Rethrow(ResourceExecutedContextSealed context) at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted) at Microsoft.AspNetCore.Mvc .Infrastructure.ResourceInvoker.InvokeFilterPipelineAsync() --- 從先前引發異常的位置結束堆棧跟蹤 --- 在 Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Awaited|17_0(ResourceInvoker 調用程序,任務任務,IDisposable 范圍) Microsoft.AspNetCore.Routing.EndpointMiddleware.g__AwaitRequestTask|6_0(端點端點,任務 requestTask,ILogger 記錄器)在 Microsoft.AspNetCore.Diagnostics.EntityFrameworkCore.MigrationsEndPointMiddleware.Invoke(HttpContext context)在 Microsoft.AspNetCore.Diagnostics.EntityFrameworkCore.DatabaseErrorPageMiddleware.Invoke( HttpContext httpContext) 在 Microsoft.Asp NetCore.Diagnostics.EntityFrameworkCore.DatabaseErrorPageMiddleware.Invoke(HttpContext httpContext) 在 Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)
數據庫上下文:
public class DBContext1 : DbContext
{
// ...
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
optionsBuilder.UseSqlServer(new string(sameConnectionString));
}
public DBContext1() : base()
{
}
public DBContext1(DbContextOptions options) : base(options)
{
}
}
public class DBContext_A : DbContext
{
public DBContext_A(DbContextOptions<DBContext_A> options) : base(options)
{
}
}
public class DBContext_B : DbContext
{
public DBContext_B(DbContextOptions<DBContext_B> options) : base(options)
{
}
}
public class DBContext_C : DbContext
{
public DBContext_C(DbContextOptions<DBContext_C> options) : base(options)
{
}
}
{
"ConnectionStrings": {
"Connection_A": "Server=(localdb)\\mssqllocaldb;Database=DB_A;Trusted_Connection=True;...",
"Connection_B": "Server=(localdb)\\mssqllocaldb;Database=DB_B;Trusted_Connection=True;...",
"Connection_C": "Server=(localdb)\\mssqllocaldb;Database=DB_C;Trusted_Connection=True;...",
}
}
services.AddDbContext<DBContext_A>(ops =>
{
ops.UseSqlServer(Configuration.GetConnectionString($"Connection_A"));
});
services.AddDbContext<DBContext_B>(ops =>
{
ops.UseSqlServer(Configuration.GetConnectionString($"Connection_B"));
});
services.AddDbContext<DBContext_C>(ops =>
{
ops.UseSqlServer(Configuration.GetConnectionString($"Connection_C"));
});
public FooController : Controller
{
private readonly DBContext_A _context_A;
private readonly DBContext_B _context_B;
private readonly DBContext_C _context_C;
public FooController(
DBContext_A context_A,
DBContext_B context_B,
DBContext_C context_C)
{
_context_A = context_A;
_context_B = context_B;
_context_C = context_C;
}
}
為每個上下文創建一個 class 庫,因此當您應用遷移時,每個上下文將在其自己的項目中擁有自己的遷移文件夾。
在多上下文解決方案中應用遷移時;
PM > add-migration Init -Context DBContext_A
PM > update-database -Context DBContext_A
PM > add-migration Init -Context DBContext_B
PM > update-database -Context DBContext_B
PM > add-migration Init -Context DBContext_C
PM > update-database -Context DBContext_C
或者,您可以使用完整的 PM cmd,如下所示:
PM > add-migration Init -Context DBContext_A -Project ClassLibrary_A -StartupProject MainProject
PM > update-database -Context DBContext_A -Project ClassLibrary_A -StartupProject MainProject
PM > add-migration Init -Context DBContext_B -Project ClassLibrary_B -StartupProject MainProject
PM > update-database -Context DBContext_B -Project ClassLibrary_B -StartupProject MainProject
PM > add-migration Init -Context DBContext_C -Project ClassLibrary_C -StartupProject MainProject
PM > update-database -Context DBContext_C -Project ClassLibrary_C -StartupProject MainProject
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