Interfaces and workarounds for differences in C# and VB

[balabaster]

I've got a hierarchy of interfaces that I need passed into a method to return a value given a value path. For instance:

Class.Property. SubProperty.Val ue

I'm using reflection to iterate through the path grabbing the sub-properties down to the "leaf" property at which point the value is returned. The basic concept is this:

Function GetValue(ByVal FreightBill As IFreightBill, ByVal ValuePath As String) As Double

  Dim AssemblyName As String = Reflection.Assembly.GetExecutingAssembly().GetName.Name

  Dim PathNodes As List(Of String) = ValuePath.Split(".").ToList
  If PathNodes(0) <> AssemblyName Then PathNodes.Insert(0, AssemblyName)

  Dim CrntInstance As Object = FreightBill
  For i As Integer = 2 To PathNodes.Count - 1
    Dim CrntType As Type = CrntInstance.GetType()
    Dim CrntProperty As String = PathNodes(i)
    Dim dynProperty As Reflection.PropertyInfo = CrntType.GetProperty(CrntProperty)
    Dim CrntValue = dynProperty.GetValue(CrntInstance, _
                                   System.Reflection.BindingFlags.GetProperty, _
                                   Nothing, _
                                   Nothing, _
                                   Nothing)
    CrntInstance = CrntValue

  Next
  Return CrntInstance

End Function

Now...even if I replace some of my properties from static classes to interfaces, in C# this will still work as when you implement an interface in C# it must have the same name as the interface, so everything works as you would expect. But if you implement an interface in VB, you can change the name of a property because each property uses the Implements keyword to implement the correct property of the interface. For example:

[Code=vb]Public Property MyIncorrectlyNa medProperty() As String Implements IMyInterface.Ac tualPropertyNam e[/Code]

Whereas in C#, you must use the correct name...

So my question I guess is in order to prevent possible problems with VB programmers calling instance properties by incorrect names, what can I do about this? Other than rapping them on the knuckles with a ruler and telling them not to do that...

[balabaster]

I wondered if creating a dynamic instance of an object that implements the interface that the property represents would help...

So if I am handling a property with some declaration to:

Interface IPropertyInterface
  Property MyValue() As String
End Interface

Interface IInstanceInterface
  Property MyProperty() As IPropertyInterface
End Interface

Public Class MyProperty
  Implements IMyProperty

  Private _MyValue As String
  Public Property MyValue() As String
    Get
      Return _MyValue
    End Get
    Set (ByVal value As String)
      _MyValue = value
    End Set
  End Property
End Class

Public Class MyInstance
  Implements IInstanceInterface

  Private _MyProperty As IPropertyInterface
  Public Property MyProperty() As IPropertyInterface Implements IInstanceInterface.MyProperty
    Get
      Return _MyProperty
    End Get
    Set (ByVal value As IPropertyInterface)
      _MyProperty = value
    End Set
  End Property
End Class

So I can use the following:

Dim oInst As New MyInstance
Dim oProp As New MyProperty
oProp.MyValue = "Hello World"
oInst.MyProperty = oProp

Dim OutStr As String = GetValue(oInst, "ObjectInstance.MyProperty.MyValue")
Console.WriteLine(OutStr)

So my GetValue method (previously posted) would iterate over the instance without any issues...but if the class that implements IInstanceInterf ace had it's MyProperty property changed to MyIncorrectlyNa med property... I'm wondering if I could grab the property rather than by name, but by the interface it implements...

[balabaster]

Actually, I think I might just like the "rap them on the knuckles" approach...

[Plater]

Actually, I think I might just like the "rap them on the knuckles" approach...

I was going to suggest you use a mallet or something larger then a ruler.

[balabaster]

I was going to suggest you use a mallet or something larger then a ruler.

That's not in the stationary budget :oP