If the DataGridView on your second form has been set up in the normal way there will be a
BindingSource
component for it. Simply set the
Filter
property of the
BindingSource
using the e-mail address you have obtained from your intermediate form.
What is displayed on your first form is to all intents irrelevant except that your second form should be identical before the filter is applied.
BindingSource.Filter[
^]