Deleting an Entity In Custom BindingList : Before deleting an entity, it's...

Wed, 25 May 2011 16:26:03 -700

Author: ting
Subject: 2716
Posted: 25-May-2011 at 4:26pm

Before deleting an entity, it's good practice to remove it from any bound lists. What happens if you move MyBase.RemoveItem(index) before entityToRemove.EntityAspect.Delete()?

Deleting an Entity In Custom BindingList : I am trying to be clever and creating...

Wed, 25 May 2011 12:53:43 -700

Author: Randar
Subject: 2716
Posted: 25-May-2011 at 12:53pm

I am trying to be clever and creating my own BindingList, which handles the adding/deleting of entity logic. That way, when I bind it to simple UltraGrids (similar to DataGrids), they should delete themselves. See http://www.ideablade.com/forum/forum_posts.asp?TID=2712&title=editable-grid-controls for some additional info. The problem is, whenever I try to delete the entity via the aspect, I get an error I don't really understand.

Here is the key parts of the code:

'''

''' This class is a wrapper around BindingList, that is incorporated directly into the the EntityManager for new/delete operations.
'''

'''
Public Class EntityBindingList(Of T)
    Inherits BindingList(Of T)

    '''

    ''' Removes the item at the specified index.
    '''

    ''' The zero-based index of the item to remove.
    ''' You are removing a newly added item and is set to false.
    Protected Overrides Sub RemoveItem(ByVal index As Integer)
        OnRemovingItem(New RemoveItemEventArgs(Me(index)))

        ' Convert this to a entity so we can access the EntityAspect
        Dim entityToRemove As Entity = TryCast(Me(index), IdeaBlade.EntityModel.Entity)
        ' Flag the entity to be deleted when the EntityManager is saved
        entityToRemove.EntityAspect.Delete()

        MyBase.RemoveItem(index)
    End Sub

End Class

When stepping through the code, as soon as I try to call EntityAspect.Delete(), I get "Unable to delete the row: Cannot call BeginEdit() on Deleted entities." Which makes no sense since I can see through the watch window, it is still flagged as "Unchanged".

I tried to not Delete it, thinking it might change it under the hood, but no luck.

So what does the error mean? Or even better, how do I fix it?

DevForce Community Forum : Deleting an Entity In Custom BindingList

Deleting an Entity In Custom BindingList : Before deleting an entity, it's...

Deleting an Entity In Custom BindingList : I am trying to be clever and creating...