	[x] Posted via EE Mobile
	Search, ask, and monitor your questions on the go with EE Mobile. Visit Experts Exchange from your mobile device and never be out of touch again.

Question

	[x] Attachment Details

[x]

The Solution Rating System

With so many solutions, how can you tell which solutions are most likely to help you and which ones are not? To provide you with a tool to use, we rate our solutions based on various elements that most accurately determine if a solution is a quality solution. To explain what factors affect the solution rating, here are the elements we take into consideration when formulating our solution rating.

The Grade of the Solution
The Zone Rank of the Expert Providing the Solution
The Number of Author and Expert Comments
The Number of Experts Contributing
The Feedback of the Community

Your Input Matters
Because of the way the system is set up, the most important variable in this equation is you. As a member of Experts Exchange, you are able to cast your vote on the quality of the solutions in regard to how complete, accurate, helpful and easy to understand each solution is. When you provide your feedback, each rating is adjusted accordingly. So, if you see a solution that has a poor rating that you think is a good solution, let us know by rating it. As you do, the rating will be adjusted and will become more accurate for other members of our site.

If you have any suggestions that you would like to make for our rating system, please ask a question in the Suggestions Zone of Community Support.

Thank you!

8.1

Need help casting base object to a type inherited from it

Asked by pbfonline in .NET, Software/Systems Design

Tags: myclass, cast, object, object oriented, inheritence, convert, ctype

What I'd like to do is have the Business Layer actually build and use an enhanced version of a base object with additional embedded functionality. But, it wouldn't expose the additional functionality outside of the business layer itself.

The assumption is that I can return the enhanced object (but cast as the base class) to the presentation layer, but it's still the same actual enhanced object.

Then when the presentation layer passes it into the business layer, the BL just type casts it back to the enhanced object (that only it knows how to use) and then can use the additional functionality of the enhanced class.

The code below compiles, but gives a type cast error when I try to run it. Shouldn't I be able to do this? If not, is there a way I can override MyBase in the enhanced object New so I can just pass the base class in the constructor of the enhanced class and set MyBase???

So, in the Person.Enhanced object, I'd add something like:

Public Sub New(ByVal pPerson As BusinessObjects.Person)
MyBase = pPerson
End Sub

And just have the GetCustomer() do the following:

Return New BusinessLogic.Person.Enhanced(BusinessLogic.Person.Create("Test", New Date(77, 1, 1)))

Get your answer NOW

         
           
             1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:
12:
13:
14:
15:
16:
17:
18:
19:
20:
21:
22:
23:
24:
25:
26:
27:
28:
29:
30:
31:
32:
33:
34:
35:
36:
37:
38:
39:
40:
41:
42:
43:
44:
45:
46:
47:

           
           
             Namespace BusinessObjects
    Public Class Person
        Public Name As String
        Public DateOfBirth As Date
    End Class
End Namespace
 
Namespace BusinessLogic
    Public Class Person
        Private Class Enhanced
            Inherits BusinessObjects.Person
 
            Public ReadOnly Property Age() As Integer
                Get
                    Return DateDiff(DateInterval.Year, MyBase.DateOfBirth, Now())
                End Get
            End Property
        End Class
 
        Private Shared Function Create(ByVal pName As String, ByVal pBirthDate As Date) As BusinessObjects.Person
            Dim tmp As New BusinessObjects.Person()
            tmp.Name = pName
            tmp.DateOfBirth = pBirthDate
            Return tmp
        End Function
 
        Public Shared Function IsOld(ByVal pPerson As BusinessObjects.Person) As Boolean
            Return DirectCast(pPerson, Person.Enhanced).Age > 55
        End Function
 
        Public Shared Function GetPerson() As BusinessObjects.Person
            Dim baseObject As BusinessObjects.Person = BusinessLogic.Person.Create("Test", New Date(77, 1, 1))
            Dim inheritedObject As Person.Enhanced = baseObject
            'Dim inheritedObject As Person.Enhanced = CType(baseObject, Person.Enhanced)
            'Dim inheritedObject As Person.Enhanced = DirectCast(baseObject, Person.Enhanced)
            Return inheritedObject
        End Function
    End Class
 
End Namespace
 
Public Class PresentationLayer
    Public Sub Test()
        Dim tmp As BusinessObjects.Person = BusinessLogic.Person.GetPerson()
        Debug.Print(BusinessLogic.Person.IsOld(tmp))
    End Sub
End Class

           
         

20091111-EE-VQP-89 - Hierarchy / EE_QW_3_20080625

Hall of Fame

1. CodeCruiser488,791
2. abel465,249
3. Idle_Mind459,720
4. TheLearn...375,874
5. Dhaest279,401
6. oobayly274,248
7. emoreau230,014
8. jpaulino220,687
9. nmarun173,575
10. jaime_oliv...167,984
11. Omego2K165,286
12. kaufmed152,382
13. webtubbs147,044
14. angelIII131,990
15. ragi0017128,710
16. spprivate112,984
17. jensfiederer110,768
18. Fernando...106,587
19. daveamour106,532
20. pivar104,000
21. sunithnair96,554
22. ToddBeau...92,560
23. guru_sami86,768
24. Juan_Bar...86,494
25. mlmcc85,515

1. TheLearn...2,427,836
2. Idle_Mind1,191,487
3. emoreau814,732
4. iboutchkine809,868
5. Dhaest672,668
6. jaime_oliv...604,776
7. jpaulino598,835
8. mmarinov556,677
9. CodeCruiser532,446
10. gregoryyo...530,316
11. Fernando...489,357
12. graye486,293
13. abel482,149
14. naveenko...451,699
15. angelIII396,098
16. webtubbs361,351
17. testn352,601
18. jensfiederer336,483
19. RobertRFr...333,569
20. YZlat332,657
21. surajguptha324,880
22. Arthur_...316,064
23. AlexFM304,664
24. VBRocks297,419
25. Mikal613280,938

Need help casting base object to a type inherited from it

Asked by pbfonline in .NET, Software/Systems Design

Tags: myclass, cast, object, object oriented, inheritence, convert, ctype

About this solution