Select Case True

Question

Apparently this used to be a way in VB6 and VBA to short circuit and execute the first true case:

Select Case True
End Select

Is this still

Answer 1

You can define Equals Operator on any Wrapper Type. Then you can use Wrapper type on Select Case.

Sample Wrapper.

Imports System.Runtime.InteropServices
 Friend Module Util
  Public Function _Is(v As Object) As IsWrapper
      Return New IsWrapper With {.Obj = v}
  End Function
  Public Structure IsWrapper
     Public Obj As Object
     Public Shared Operator =(ByVal a As IsWrapper, ByVal b As Object) As Boolean
         Return a.Obj Is b
     End Operator
     Public Shared Operator <>(ByVal a As IsWrapper, ByVal b As Object) As Boolean
         Return a.Obj IsNot b
     End Operator
  End Structure
End Module

Now you can use _is(AnyObject):

Private Sub RbClass_CheckedChanged(sender As System.Object, e As System.EventArgs)
    If DirectCast(sender, RadioButton).Checked = False Then Return
    Select Case _Is(sender)
        Case RbClass : Rb = 0
        Case RbTablePredicate : Rb = 1
        Case RbTableRowFilter : Rb = 2
    End Select
    QueryCtl1_QueryChanged(Nothing, Nothing)
End Sub

Public Sub Predicate(ByVal PredicateType As Type, ByVal Op As Operadores, ByVal Obj As Object, ByVal CompareOptions As CompareOptions, ByVal Fnc As [Delegate])
   Dim pred As [Delegate] = Nothing
   Select Case _Is(PredicateType)
      Case GetType(Boolean)
          pred = New Predicate(Of Boolean)(Function(v) v)
      Case GetType(String)
          pred = StrPredicate(Op, Obj, CompareOptions)
      Case Else 'Utilizar Generics
          pred = GenericHelper.Builder(PredicateType).Predicate(Op, Obj)
   End Select
   Predicate(pred, Fnc)
End Sub

About Performance. Release Code is optimized. Wrapper has no performance penalty.