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!

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;
    }

}