Override delete function in entity framework

Question

How can I make my own delete method to prevent that the data really gets deleted? I want to set a datetime field when it gets deleted instead of a normal delete.

I read about overriding the submitchanges function, but I don't get it to work

Answer 1

Handle SavingChanges, go through the deleted items in the context, change their state to modified, and modify the field in question.

Answer 2

I wrote an interface IRequiredColumns with the properties CreatedOn, ModifiedOn and DeletedOn which every entity implements. Then I created this partial class for the context:

Partial Public Class Context
Public Overrides Function SaveChanges(ByVal options As System.Data.Objects.SaveOptions) As Integer
    For Each entry As ObjectStateEntry In ObjectStateManager.GetObjectStateEntries(EntityState.Added Or EntityState.Modified Or EntityState.Deleted)
        If TypeOf (entry.Entity) Is IRequiredColumns Then
            Dim entity As IRequiredColumns = CType(entry.Entity, IRequiredColumns)

            Select Case entry.State
                Case EntityState.Added
                    entity.CreatedOn = Now
                Case EntityState.Modified
                    entity.ModifiedOn = Now
                Case EntityState.Deleted
                    entry.ChangeState(EntityState.Modified)
                    entity.DeletedOn = Now                        
            End Select
        End If
    Next

    Return MyBase.SaveChanges(options)
End Function
End Class

This works great for me!