Click to deselect single-select listbox

I want to make a single-select listbox deselect the selected item when you click on it (like a simple multiselect, except that only one item can ever be selected). Is there a simple way to do this? Or would it be easier to come at it the other way and make a simple multiselect listbox that deselects an old item when you select a new one?

like this?...

Code:

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Private Sub ListBox1_SelectedIndexChanged(sender As System.Object, e As System.EventArgs) Handles ListBox1.SelectedIndexChanged
    ' NOTE: ListBox1.SelectionMode = SelectionMode.One
    Static lastIndex As Integer = -1
    If ListBox1.SelectedIndex > -1 Then
        If lastIndex > -1 Then
            If lastIndex = ListBox1.SelectedIndex Then
                ListBox1.SelectedIndex = -1
            End If
        End If
    End If
    lastIndex = ListBox1.SelectedIndex
End Sub

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Edit, or simply?...

Code:

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Private Sub ListBox1_SelectedIndexChanged(sender As System.Object, e As System.EventArgs) Handles ListBox1.SelectedIndexChanged
    Static lastIndex As Integer = -1
    If lastIndex = ListBox1.SelectedIndex Then
        ListBox1.SelectedIndex = -1
    End If
    lastIndex = ListBox1.SelectedIndex
End Sub

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try this. it's not perfect, but close to what you want:

Code:

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Public Class Form1

    Private canSelect As Boolean = True

    Private Sub ListBox1_MouseClick(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles ListBox1.MouseClick
        If ListBox1.IndexFromPoint(e.Location) = -1 Then Return
        If Not canSelect Then
            ListBox1.SelectedItem = Nothing
        End If
        canSelect = Not canSelect
    End Sub

End Class

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That first one works perfectly, although I'm not exactly sure how.