EF有很少的擴展點。所以有時很難定製。
這個答案是我previous answer
public abstract class Entity
{
public virtual void OnBeforeInsert(){}
public virtual void OnBeforeUpdate(){}
}
public class Category : Entity
{
public string Name { get; set; }
public string UrlName{ get; set; }
public override void OnBeforeInsert()
{
//ur logic
}
}
然後在您的DbContext
類訂閱ObjectStateManagerChanged
事件ObjectStateManager
的延伸。
public class MyContext : DbContext
{
public override int SaveChanges()
{
//intercept entity changes
UnderlyingObjectContext.ObjectStateManager.ObjectStateManagerChanged
+= OnObjectStateManagerChanged;
var changedEntities = ChangeTracker.Entries();
foreach (var changedEntity in changedEntities)
{
if (changedEntity.Entity is Entity)
{
var entity = (Entity)changedEntity.Entity;
switch (changedEntity.State)
{
case EntityState.Added:
entity.OnBeforeInsert();
break;
case EntityState.Modified:
entity.OnBeforeUpdate();
break;
}
}
}
return base.SaveChanges();
}
ObjectContext UnderlyingObjectContext
{
get
{
return ((IObjectContextAdapter)this).ObjectContext;
}
}
void OnObjectStateManagerChanged(object sender, CollectionChangeEventArgs e)
{
if (e.Action == CollectionChangeAction.Add)
{
//not all added entities are new
if (UnderlyingObjectContext.ObjectStateManager
.GetObjectStateEntry(e.Element).State == EntityState.Added)
{
if (e.Element is Entity)
{
((Entity)e.Element).OnBeforeInsert();
}
}
}
}
}
如果您使用的是EF 4.0,則需要相應地對其進行自定義。
檢查[這個答案](http://stackoverflow.com/questions/7041178/on-insert-update-logic-in-ef-code-first/7041363#7041363) – Eranga
@Eranga:謝謝,請參閱更新。 – Naor