returning a structure from a form

[kebo]

My code:

Private Sub SelectStrategy()
        Dim f As New Strategies.SelectStrategyfrm      
        f.ShowDialog()
        If Not f.SelectedStrategy Is Nothing Then  '<====no good!!! ERROR! DANGER WILL ROBINSON!
'                                                      the error is  'Is' requires operands that have
'                                                        reference types, but this operand has the value type 'Globals.StrategyStruct'.
            MyOptions.CurrentStrategy = f.SelectedStrategy
        End If
        f.Dispose()
    End Sub

My goal:
The form being created prompts the user for information. If the user selects something a public structure is populated and the form closes, no problem. If however, the user selects Cancel, the public structure is set to Nothing and the form closes.

Private Sub Cancel_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Cancel.Click
        SelectedStrategy = Nothing
        Me.Close()
    End Sub

But as you see in the first code segment, I have pointed out that I get an error.

I don't understand the error. If I can use

SelectedStrategy = Nothing

why can't I use

If Not f.SelectedStrategy Is Nothing Then

and how do I propery do what I am trying to do?
thanks
kevin