我为了在记录被更改时添加上一个最新的修改时间戳,扩展了一个类。类似于这里的代码完成了这个操作。
我的问题是
然而,通过base.SaveChanges()调用,EF确实更新了这条记录。
下面是MasterTable的扩展部分:
我的问题是
SaveChanges()
会对两次更改都进行检测,但第二次更改并没有进入循环:没有对象被检测到需要更改。然而,通过base.SaveChanges()调用,EF确实更新了这条记录。
下面是MasterTable的扩展部分:
namespace AuditTestEF
{
public interface IHasAuditing
{
DateTime LastModifiedOn { get; set; }
int LastModifiedBy { get; set; }
}
public partial class MasterTable : IHasAuditing
{
}
public class AuditTestEntitiesWithAuditing : AuditTestEntities
{
public int TestingUserIs = 1;
public override int SaveChanges()
{
foreach (ObjectStateEntry entry in (this as IObjectContextAdapter)
.ObjectContext
.ObjectStateManager
.GetObjectStateEntries(EntityState.Added | EntityState.Modified))
{
// This loop is entered the first time, but not the second
if (entry.IsRelationship) continue;
var lastModified = entry.Entity as IHasAuditing;
if (lastModified == null) continue;
lastModified.LastModifiedOn = DateTime.UtcNow;
lastModified.LastModifiedBy = TestingUserIs;
}
return base.SaveChanges();
}
}
}
以下是测试工具:
[TestMethod]
public void TestMethod1()
{
MasterTable mtOriginal;
using (var audit = new AuditTestEntitiesWithAuditing())
{
var message = "Hello";
audit.TestingUserIs = 1;
mtOriginal = new MasterTable {TextField = message};
audit.MasterTable.Add(mtOriginal);
audit.SaveChanges();
// This test passes, TestingUser is set in the override
Assert.IsTrue(mtOriginal.LastModifiedBy == audit.TestingUserIs);
}
using (var audit = new AuditTestEntitiesWithAuditing())
{
var mt = audit.MasterTable.Find(mtOriginal.MasterTableId);
mt.TextField = "Goodbye";
audit.TestingUserIs = 4;
audit.SaveChanges();
// This test fails, the record is written with "Goodbye" but
// GetObjectStateEntries(EntityState.Added | EntityState.Modified) has no entries.
Assert.IsTrue(mt.LastModifiedBy == audit.TestingUserIs);
}
}
这里没有其他代码。也没有奇怪的关闭/开启实体跟踪或其他什么东西。所见即所得。
我错过了什么?为什么明显修改过的对象被修改检查忽略了?