System.Data.SqlTypes.SqlNullValueException我从net core 3.1迁移到net5.0后

Question

我在其中一项提取服务中遇到此错误

System.Data.SqlTypes.SqlNullValueException HResult=0x80131931
Message=Data is Null. This method or property cannot be called on Null values. Source=Microsoft.Data.SqlClient StackTrace: at Microsoft.Data.SqlClient.SqlBuffer.get_Int32() at Microsoft.EntityFrameworkCore.Query.Internal.SingleQueryingEnumerable1.Enumerator.MoveNext() at System.Collections.Generic.List1..ctor(IEnumerable1 collection) at System.Linq.Enumerable.ToList[TSource](IEnumerable1 source) at Infrastructure.Data.Repository.Base.EfRepository1.List(ISpecification1 spec) in C:\mydir\master\src\DataTier\SMYLS.Data.Respository\Repository\Base\EfRepository.cs:line 88 at ApplicationCore.Services.Items.ItemService.SearchItems(ItemSearchDataModel searchModel) in C:\mydir\master\src\ServiceTier\SMYLS.Services\Items\ItemService.cs:line 202 at Web.Controllers.Api.InvoiceController.GetItemList(ItemSearchDataModel searchModel) in C:\mydir\master\src\Web\Controllers\Api\InvoiceController.cs:line 322 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()

This exception was originally thrown at this call stack: [External Code] Infrastructure.Data.Repository.Base.EfRepository.List(ApplicationCore.Interfaces.Repository.ISpecification) in EfRepository.cs ApplicationCore.Services.Items.ItemService.SearchItems(ApplicationCore.DTOs.Items.ItemSearchDataModel) in ItemService.cs Web.Controllers.Api.InvoiceController.GetItemList(ApplicationCore.DTOs.Items.ItemSearchDataModel) in InvoiceController.cs [External Code]

这是我迁移到net5.0后发生的。如果我运行我的netcore3.1，完全没有问题。 我研究了这个错误，发现大部分错误是由于您的模型需要一个必需的 属性 但数据库 returns 是一个空值。我检查了我的模型，但它们看起来很好（它们在 3.1 上工作没有任何问题）

这些是我的模型属性

public string Name { get; set; }
public string Description { get; set; }
public decimal Cost { get; set; }
public bool Active { get; set; }
public DateTime UpdatedDateUtc { get; set; }
public int UpdatedBy { get; set; }
public int ClinicId { get; set; }
public int? ServiceGroupId {get;set;}
public string ShortCode { get; set; }
public int? IndustryCodeId { get; set; }
public bool Subscription { get; set; }
public bool BlockBill { get; set; }
public decimal? DiscountPercentage { get; set; }
#nullable enable
public string? SubscriptionType { get; set; }
public virtual Clinic Clinic { get; set; }
public virtual SiteUser UpdatedByNavigation { get; set; }
public virtual ServiceGroup ServiceGroup { get; set; }
public virtual IndustryCode IndustryCode { get; set; }
public virtual ICollection<InvoiceItem> InvoiceItem { get; set; }
public virtual ICollection<DoctorPricing> DoctorPricing { get; set; }
public virtual ICollection<DoctorPricingHistory> DoctorPricingHistory { get; set; }

这些是我来自数据库的样本数据

仍然无法弄清楚为什么这在 net5.0 中不起作用

Answer 1

快速浏览一下，我怀疑 ServiceGroup 属性，它具有 ServiceGroup 的 return 类型，但对应于可为 null 的 ServiceGroupId 数据库中的列。我希望 属性 的 return 类型需要是 ServiceGroup? 才能允许空值。

我不确定为什么在 ASP.NET Core 3.x 中没有抛出异常。我怀疑 ASP.NET 核心 5.x 在运行时执行引用类型的可空性方面做得更好，从而提高了对数据模型中长期存在的差异的认识。