我如何获得实体的旧价值？
我如何获得实体的旧价值？
下面的例子..
public void Update(User user)
ValidateEntity(user, OperationType.Update);
oldUser = (how do I get the old values (database) of the entity User?)
Set.Attach(user);
Context.ObjectStateManager.ChangeObjectState(user, EntityState.Modified);
Context.SaveChanges();
OnUpdated(user, oldUser);
}
尝试这个：
public void Update(User user)
ValidateEntity(user, OperationType.Update);
var oldUser = Set.Single(u => u.Id == user.Id);
Context.Detach(oldUser);
Set.Attach(user);
Context.ObjectStateManager.ChangeObjectState(user, EntityState.Modified);
Context.SaveChanges();
OnUpdated(user, oldUser);
}
或这个：
public void Update(User user)
{
ValidateEntity(user, OperationType.Update);
var oldUser = Set.Single(u => u.Id == user.Id);
Set.ApplyCurrentValues(user);
Context.SaveChanges(SaveOptions.DetectChangesBeforeSave);
OnUpdated(user, Context.ObjectStateManager.GetOjectStateEntry(user).OriginalValues);
Context.AcceptAllChanges();
}
我找到了一种使用反射将DbDataRecord转换为实体类型的方法...
其中http://www.instanceofanobject.com/2011/01/ef4-dbdatarecord-convertto.html
public static class AnonymousTypeConversion
{
///
/// Converts a single DbDataRwcord object into something else.
/// The destination type must have a default constructor.
///
///
///
///
public static T ConvertTo(this DbDataRecord record)
{
T item = Activator.CreateInstance();
for (int f = 0; f
/// Converts a list of DbDataRecord to a list of something else.
///
///
///
///
public static List ConvertTo(this List list)
{
List result = (List)Activator.CreateInstance>();
list.ForEach(rec =>
{
result.Add(rec.ConvertTo());
});
return result;
}
}
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