EF Core 未引发 ValidationException

Question

我有一个DbContext像这样的基类

public abstract class DbContextBase : DbContext
{
    public DbContextBase()
    {
    }

    public DbContextBase(DbContextOptions options)
        : base(options)
    {
    }

    public override int SaveChanges()
    {
        this.ValidateEntities();

        return base.SaveChanges();
    }

    public override Task<int> SaveChangesAsync(CancellationToken cancellationToken = default(CancellationToken))
    {
        this.ValidateEntities();

        return base.SaveChangesAsync(cancellationToken);
    }

     public override Task<int> SaveChangesAsync(bool acceptAllChangesOnSuccess, CancellationToken cancellationToken = default(CancellationToken))
     {
        this.ValidateEntities();

        return base.SaveChangesAsync(acceptAllChangesOnSuccess, cancellationToken);
    }

    protected virtual void ValidateEntities()
    {
        var entities = this.ChangeTracker.Entries().
                            Where(s => s.State == EntityState.Added || s.State == EntityState.Modified);

        foreach (var entity in entities)
        {
            var validationContext = new ValidationContext(entity);
            Validator.ValidateObject(entity, validationContext);
        }
    }
}

我的所有 Db Context 类都继承自该基类。问题是，即使存在验证违规，该行Validator.ValidateObject()也不会抛出。ValidationException在调试器中我可以看到这一行已被执行。例如，对于下面的模型类，我尝试使用SaveChangesAsync()set Nameto进行调用null，但验证通过了：

public class MyModel : IEntity<long>
{
    [Key]
    public long Id { get; set; }

    [Required]
    public string Name { get; set; }
}

IEntity<T>只是将属性强加于Id所有模型。

Answer 1

问题是该变量entity不保存实体实例，而是更改 tracker ( EntityEntry) 实例，因此代码试图验证错误的东西。

因此，要么重命名变量并使用entry.Entity属性：

var entries = this.ChangeTracker.Entries()
    .Where(s => s.State == EntityState.Added || s.State == EntityState.Modified);

foreach (var entry in entries)
{
    var validationContext = new ValidationContext(entry.Entity);
    Validator.ValidateObject(entry.Entity, validationContext);
}

或保持代码不变，但确保entities变量保存可枚举的实体实例：

var entities = this.ChangeTracker.Entries()
    .Where(s => s.State == EntityState.Added || s.State == EntityState.Modified)
    .Select(s => s.Entity); // <--