ASP.NET CORE 存储过程错误：InvalidCastException

Question

Good day, I have this store procedure because of the recursion of the query if I will put this on to LINQ style of code or procedural, it will may cause performance issue along the way.

so I have this store procedure

CREATE PROCEDURE GetReferralTree @parentID nvarchar(450)
AS

WITH referral_CTE (Id, Fullname, Referral)AS  
(  
   SELECT dbo.AspNetUsers.Id,dbo.AspNetUsers.Fullname, dbo.AspNetUsers.Referral from AspNetUsers  where Id = @parentID
   union all
   SELECT AspNetUsers.Id, AspNetUsers.Fullname, AspNetUsers.Referral
   from AspNetUsers   
   JOIN referral_CTE ON AspNetUsers.Referral = referral_CTE.id
)  
SELECT distinct * FROM referral_CTE 

GO;

and I called it on my asp.net core web app

[HttpGet]
    public ActionResult GetReferralTree(string id)
    {
        List<ReferralTreeViewModel> hierarchy = new List<ReferralTreeViewModel>();
        var parentIDParam = new SqlParameter("@parentID", id);
        hierarchy = (List<ReferralTreeViewModel>)_context.AspNetUsers.FromSqlRaw("exec GetReferralTree @parentID ", parentIDParam)
            .Select(x => new ReferralTreeViewModel()
            {
                Id = x.Id,
                Fullname = x.Fullname,
                ParentId = x.Referral
            })
            .AsEnumerable() ;
        return Ok(hierarchy);
    }

but returns something like this

    System.InvalidCastException: Unable to cast object of type 'Microsoft.EntityFrameworkCore.Query.Internal.EntityQueryable`1[Genea.Areas.Admin.Models.ReferralTreeViewModel]' to type 'System.Collections.Generic.List`1[Genea.Areas.Admin.Models.ReferralTreeViewModel]'.
   at Genea.Areas.Admin.Controllers.GenealogyController.GetReferralTree(String id) in C:\Users\winshiero\source\repos\Genea\Areas\Admin\Controllers\GenealogyController.cs:line 43
   at lambda_method(Closure , Object , Object[] )
   at Microsoft.Extensions.Internal.ObjectMethodExecutor.Execute(Object target, Object[] parameters)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor.SyncActionResultExecutor.Execute(IActionResultTypeMapper mapper, ObjectMethodExecutor executor, Object controller, Object[] arguments)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeActionMethodAsync()
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeNextActionFilterAsync()
--- End of stack trace from previous location where exception was thrown ---
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Rethrow(ActionExecutedContextSealed context)
   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.<InvokeNextResourceFilter>g__Awaited|24_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean 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()
--- End of stack trace from previous location where exception was thrown ---
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Awaited|17_0(ResourceInvoker invoker, Task task, IDisposable scope)
   at Microsoft.AspNetCore.Routing.EndpointMiddleware.<Invoke>g__AwaitRequestTask|6_0(Endpoint endpoint, Task requestTask, ILogger logger)
   at AspNetCoreHero.ToastNotification.Middlewares.NotyfMiddleware.InvokeAsync(HttpContext context, RequestDelegate next)
   at Microsoft.AspNetCore.Builder.UseMiddlewareExtensions.<>c__DisplayClass5_1.<<UseMiddlewareInterface>b__1>d.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Diagnostics.EntityFrameworkCore.MigrationsEndPointMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Diagnostics.EntityFrameworkCore.DatabaseErrorPageMiddleware.Invoke(HttpContext httpContext)
   at Microsoft.AspNetCore.Diagnostics.EntityFrameworkCore.DatabaseErrorPageMiddleware.Invoke(HttpContext httpContext)
   at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)

Answer 1

Try to use this:

    [HttpGet]
    public ActionResult<List<ReferralTreeViewModel>> GetReferralTree(string id)
    {
            var parentIDParam = new SqlParameter("@parentID", id);
       var  hierarchy = _context.AspNetUsers.FromSqlRaw("exec GetReferralTree @parentID ", 
          parentIDParam).ToArray();
          var result  hierarchy.Select(x => new ReferralTreeViewModel
            {
                Id = x.Id,
                Fullname = x.Fullname,
                ParentId = x.Referral
            }).ToList();
           
        return Ok(result);
    }