ascx control values in aspx page

[giridharprasad]

I have a master page that has two content placeholders. I am loading the first content placeholder with a user control that has 3 text boxes. In the second content placeholder I am populating a dropdown from an XML file. In an aspx page where this master page is applied, there is a submit button, on click of which I need to retrieve the values from text boxes in the content placeholder1(User control) as well from Content placeholder2 (Dropdown) and write them down inot a text file.
My problem here is that I donot know how to retrieve values from ascx and use it in aspx page.
Any help woluld be much appreciated.
Thanks in advance.