Page lifecycle question

I am using a DropDown menu and an UpdatePanel to filter out a DataGrid. The DataGrid has buttons which redirect to a different page. When I hit the back button or a link on top of the other page, it redirects me to the page with the DropDown as it should...but it gets rid of the DataGrid data and I have to make a selection from the DropDown again. Is there开发者_StackOverflow中文版 a way to make sure that the DropDown selection is remembered when both the link is pressed and the back button selected? Thanks for your help!

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The easiest thing to do in this case is to save the dropdown selection in Session collection and on page load, check to see if there is a saved selection and use it to reapply the selection.

protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{

    Session["SavedSelection"] = DropDownList1.SelectedIndex;
}

protected void Page_Load(object sender, EventArgs e)
{
    if(Session["SavedSelection"] != null)
    {
        int  selectedIndex = (int) Session["SavedSelection"];
        DropDownList1.SelectedIndex = selectedIndex;
    }

}