checkboxes as children checked/unchecked don't save to database

I finally got all checkboxes to check/uncheck with code that Chris wrote to me about in http://forums.asp.net/p/1314020/2651459.aspx#2651459, so I appreciate that. Now, however, I have the following problems that I need help with, please: (1) The page still flickers, so it's apparent that I'm missing some AJAX concepts; and (2) when I click the Update button, the new checkbox values don't save to the database.

Protected Sub chkAll_CheckedChanged(ByVal sender As Object, ByVal e As EventArgs)
   'will become true if the main checkbox is checked
   Dim parentCheckBox As CheckBox = CType(sender, CheckBox)Dim isParentChecked As Boolean = parentCheckBox.Checked 
   'should get all the main controls in your form
   For Each cntrl As Control In Page.Form.Controls
      If Left(cntrl.ID, 3) = "chk" And cntrl.ID <> "chkAll_Edit" Then
& ...