in the child window create a global object of whatever type it's parent is. set a property up so that is may be set/get (get probably isn't that important here, but let's do it properly). before you call 'myChild.ShowDialog()', pass the parent to it with a piece of code that will look a bit like 'myChild.parentProperty = this'. the cild now has a reference to it's parent, use it as you wish.
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