[英]How to fix Entity Framework Core error "Value cannot be null. Parameter name: frameworkName"?
使用 EF Core (3.0.0-preview6.19304.10) 的预发布版本。 当我调用DbContext.SaveChanges()
,它会导致错误
值不能为空。 参数名称 frameworkName
这是上下文类
using EFPersistence.Configurations;
using EFPersistence.Models;
using Microsoft.EntityFrameworkCore;
namespace EFPersistence.Contexts
{
public class EFContext : DbContext
{
public EFContext() : base()
{
}
public DbSet<ISRSetting> ISRSettings { get; set; }
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
optionsBuilder.UseSqlServer(@"Data Source=DESKTOP-4S1AA2T\SQLEXPRESS;Initial Catalog=TestEF;Integrated Security=True");
}
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.ApplyConfiguration(new ISRSettingsConfiguration());
modelBuilder.ApplyConfiguration(new ISRDemographicSettingsConfiguration());
}
}
}
机型配置:
public class ISRSettingsConfiguration : IEntityTypeConfiguration<ISRSetting>
{
public void Configure(EntityTypeBuilder<ISRSetting> builder)
{
// PK
builder.HasKey(p => p.Id).ForSqlServerIsClustered();
builder.Property(p => p.Id)
.ValueGeneratedOnAdd();
builder.ToTable("ISRSettings");
}
}
public class ISRDemographicSettingsConfiguration : IEntityTypeConfiguration<ISRDemographicSetting>
{
public void Configure(EntityTypeBuilder<ISRDemographicSetting> builder)
{
// PK
builder.HasKey(p => p.Id).ForSqlServerIsClustered();
builder.Property(p => p.Id)
.ValueGeneratedOnAdd();
builder.ToTable("ISRSettingsDemographics");
// FK
builder
.HasOne(p => p.ISRSettings)
.WithMany(p => p.DemographicsSettings)
.HasForeignKey(p => p.ISRSettingsId)
.OnDelete(DeleteBehavior.Cascade);
}
}
和实体:
static void SeedData(EFBaseRepository<EFContext, ISRSetting, ISRSetting, int> baseRepository)
{
Console.WriteLine("Adding 1 entity");
baseRepository.Add(CreateISRSettings(0)); // Works:
Console.WriteLine("Added 1 entity");
baseRepository.SaveChanges();
}
这是错误堆栈跟踪
在 Microsoft.EntityFrameworkCore.Metadata.Internal.ClrAccessorFactory'1.Create(PropertyInfo propertyInfo, IPropertyBase propertyBase)
在 Microsoft.EntityFrameworkCore.Internal.NonCapturingLazyInitializer.EnsureInitialized[TParam,TValue](TValue&target, TParam param, Func'2 valueFactory)
在 Microsoft.EntityFrameworkCore.ChangeTracking.Internal.InternalEntityEntry.WritePropertyValue(IPropertyBase propertyBase, Object value)
在 Microsoft.EntityFrameworkCore.ChangeTracking.Internal.InternalEntityEntry.SetProperty(IPropertyBase propertyBase, Object value, Boolean setModified, Boolean isCascadeDelete, CurrentValueType valueType)
在 Microsoft.EntityFrameworkCore.ChangeTracking.Internal.InternalEntityEntry.SetProperty(IPropertyBase propertyBase, Object value, Boolean setModified, Boolean isCascadeDelete)
在 Microsoft.EntityFrameworkCore.ChangeTracking.Internal.InternalEntityEntry.AcceptChanges()
在 Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.AcceptAllChanges(IReadOnlyList'1 changedEntries)
在 Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChanges(Boolean acceptAllChangesOnSuccess)在 Microsoft.EntityFrameworkCore.DbContext.SaveChanges(Boolean acceptAllChangesOnSuccess)
在 EFPersistence.Repositories.EFBaseRepository'4.SaveChanges() 在 C:\\Projects\\EFImplementationRepo\\EFPersistance\\Repositories\\EFBaseRepository.cs:line 154
在 EFImplementationRepo.Program.SeedData(EFBaseRepository'4 baseRepository) 在 C:\\Projects\\EFImplementationRepo\\EFImplementationRepo\\Program.cs:line 31
在 EFImplementationRepo.Program.Main() 在 C:\\Projects\\EFImplementationRepo\\EFImplementationRepo\\Program.cs:line 16
本周我们将应用程序更新为 EF Core 3.1,但遇到了相同错误消息的问题。 原因是,我们有没有 setter 的集合导航属性。 GitHub 上已经存在问题。
目前, DbContext.SaveChanges()
正在工作,保存数据后抛出异常。 这种方式对我有用:
void CallSaveChanges()
{
try
{
_baseRepository.SaveChanges();
}
catch (ArgumentNullException) { }
}
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.