VB.NET hide a property member - asp.net

Question

I am currently working on the return class. The problem is I want to show the certain member only when some of the condition meet. Below is my code. I only want to show ResponseMsg member when the ResponseCode is 99 otherwise it will be hidden.
Public Class LoginResponse
Public Property TerminalID As String
Public Property ReaderID As String
Public Property TransRef As String
Public Property TransDateTime As String
Public Property Timeout As Integer
Public Property ResponseCode As String
Public Property ResponseMsg As String
Public Property Cryptogram As String
End Class

Answer 1

You can't that I know of. But you can do something like this:
Public Property ResponseMsg
Get
If ResponseCode <> SomeCodeValue
Return _responseCode
Else
Return Nothing
End if
End Get
End Property

Answer 2

You might want to think about making a specialized class.
Let's say you have your basic LoginResponse
Public Class LoginResponse
Public Property TerminalID As String
Public Property ReaderID As String
Public Property TransRef As String
Public Property TransDateTime As String
Public Property Timeout As Integer
Public Property ResponseCode As String
' Note: no ResponseMsg here
Public Property Cryptogram As String
End Class
Then you'd have an extended response class inheriting your basic LoginResponse:
Public Class LoginResponseEx : Inherits LoginResponse
Public Property ResponseMsg As String
End Class
Then where ever you create those LoginResponse objects, you just create one of the apropriate.
Let's say you have a GetResponse() procedure like:
Public Function GetResponse() As LoginResponse
Dim result As LoginResponse = Nothing
Dim code As Integer = GetSomeCode()
' ... get the other properties
' Say you have a const or something with the appropriate code: SPECIAL_CODE
If code = SPECIAL_CODE Then
Dim msg As String = GetSomeMessage()
result = New LoginResponseEx(..., code, msg, ...) ' have a special Response
Else
result = New LoginResponse(..., code, ...) ' have a normal Response
End If
Return result
End Function
Finally when checking the response you just check whether you have a special value in ResponseCode and cast the object respectivly.
'...
Dim resp as LoginResponse = GetResponse()
If resp.ResponseCode = SPECIAL_CODE Then
Dim respx as LoginResponseEx = CType(resp, LoginResponseEx)
Console.WriteLine("ResponseMessage was: " & respx.ResponseMsg
Else
Console.WriteLine("No ResponseMessage")
End If
'...
This way you have your basic LoginResponse with the ResponseMsg hidden in the special class ResponseLoginEx
Note when you do this you should think about how you implement virtual classes. e.g. the fields might have to be declared as Protected instead of Private, though i'm sure you'll do fine.
This also works with Serializable classes, of course.