private void txt_Username_TextChanged(object sender, TextChangedEventArgs e)
 {
     connect = new CTUConnection();                     // refreshens the 'CTUConnection' class //
     connect.SelectCustomer();                          //*Selects the specified columns in the Patient table*//
     connect.SearchCustomerUsername(txt_Username.Text); //Searches the customer's 'name' within the populated table//
     DGV_Cust.ItemsSource = connect.dataset;            //*All the selected fields are filtered inside the table and stored inside the grid-view*//
 }