How to connect dynamically created controls: two dropdownlist and sqldatasourse for them?

Question

ASP.NET

Hello.
I dynamically create two dropdownlist and sqldatasourse page_load for them:
dropdownlist1 takes data from sqldatasourse1, and dropdownlist2 takes data from sqldatasourse, but the problem is that the query in sqldatasourse2 contains where parameter is set by dropdownlist1 value.
And it turns out that I create a page, select a value from dropdownlist1 (turned on ispostback) and want my data to appear depending on the first grid, but instead the value for where is always the same - 1.
Who faced a similar problem or who Can you explain how to scatter the code, taking into account the life cycle of the page, or how to save, and then, when the page is "russified", restore the state to ispostback?

Answer 1

XMLHttpRequest.
dropdownlist1 - when an element is selected, a request is sent, the response to it is placed in dropdownlist2.