覆盖SaveChangesAsync

Question

有谁知道如何覆盖SaveChangesAsync？我知道张贴了类似的问题，但没有答案。我下面有以下代码：

public override async Task<int> SaveChangesAsync()
{
    PerformFurtherValidations();
    return await base.SaveChangesAsync();
}

在生成过程中，我收到以下错误消息：

错误SaveChangesAsync（）：返回类型必须 System.Threading.Tasks.Task<int>与覆盖的成员匹配 System.Data.Entity.DbContext.SaveChangesAsync()

Answer 1

public override async Task<int> SaveChangesAsync(CancellationToken cancellationToken = default(CancellationToken))
{
    return (await base.SaveChangesAsync(true, cancellationToken));
}

Answer 2

老问题，但我遇到了类似的问题并使用以下代码解决了它：

    public override async Task<int> SaveChangesAsync()
    {
        foreach (var history in this.ChangeTracker.Entries()
            .Where(e => e.Entity is IModificationHistory && (e.State == EntityState.Added ||
                e.State == EntityState.Modified))
            .Select(e => e.Entity as IModificationHistory)
            )
        {
            history.DateModified = DateTime.Now;
            if (history.DateCreated <= DateTime.MinValue)
            {
                history.DateCreated = DateTime.Now;
            }
        }
        int result = await base.SaveChangesAsync();
        foreach (var history in this.ChangeTracker.Entries()
                                        .Where(e => e.Entity is IModificationHistory)
                                        .Select(e => e.Entity as IModificationHistory))
        {
            history.IsDirty = false;
        }
        return  result;
    }

自定义 SaveChangesAsync() 允许我调整脏标志、创建日期和修改日期。