2

我有那个代码:

public class BaseClass{
    [ConcurrencyCheck]
    [Timestamp]
    public byte[] RowVersion { get; set; }
}

public class User : BaseClass
{
    public string UserName { get; set; }
}

public class Context : DbContext{
    public DbSet<User> Users { get; set; }
...
    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
     modelBuilder.Entity<User>().Property(b => b.RowVersion)
            .ValueGeneratedOnAddOrUpdate()
            .IsConcurrencyToken();//It should not be necessary because I already specified in annotation
    }
    public override int SaveChanges()
    {
        var changes = ChangeTracker.Entries<BaseClass>().Where(p => p.State == EntityState.Modified).Select(u => u.Entity);
        foreach (var change in changes)
        {
            Entry(change).Property(u => u.RowVersion).OriginalValue = new byte[] { 0, 0, 0, 0, 0, 0, 0, 120 };
        }
        return base.SaveChanges();
    }
}

public class UserBusiness
{

     public void Update(User user)
    {
        using(var ctx=new Context())
       {
        var editedUser=ctx.Set<User>().Where(u => u.Id == user.Id).FirstOrDefault();
        editedUser.RowVersion = new byte[] { 0, 0, 0, 0, 0, 0, 0, 120 }; 
        ctx.SaveChanges();
       }
     }
}

我希望在 db 中发现 RowVersion 发生了变化,但是是一样的。editedUser.RowVersion 发生变化,变化跟踪器检测到变化,但调用 SaveChanges() 后,数据库中的 rowVersion 具有相同的初始值。

4

0 回答 0