Visual Basic

...
Private _childForm as MyChildFormClass = nothing
...
Private Sub OpenMyChildForm()
    If (_childForm Is Nothing) Then
        _childForm = new MyChildFormClass()
        _childForm.Show()
    Else
        _childForm.Activate()
    End If
End Sub

  Dim o As Cx, o2 As Object
  Dim p1 As Long, p2 As Long
...
  Set o = New Cx
  Set o2 = o
...
  p1 = 0: p2 = 0
  o.Encoder p1, p2 ' Call by vtable => early binding
  p1 = 0: p2 = 0
  o2.Encoder p1, p2 ' Call by GetIdsOfName&Invoke => late binding
  p1 = 0: p2 = 0
  CallByName o, "Encoder", VbMethod, p1, p2 ' forcible late binding
  p1 = 0: p2 = 0
  CallByName o2, "Encoder", VbMethod, p1, p2

STDMETHODIMP Cx::Encoder(/*[out]*/ long * Result, /*[out]*/ long * LastError)
{
	*Result = 22;
	*LastError = 222;
	return S_OK;
}

<code>
  Dim o As Cx, o2 As Object  
  Dim p1 As Long, p2 As Long
...
  Set o = New Cx  
  Set o2 = o
...  
  p1 = 0: p2 = 0  
  o.Encoder p1, p2 ' Call by vtable => early binding
</code>

<code>
STDMETHODIMP Cx::Encoder(/*[out]*/ long * Result, /*[out]*/ long * LastError)
{	    
            *Result = 22;	
            *LastError = 222;	
            return S_OK;
}
</code>