Hi , i want to ask something related to this thread.

I want to add a new DropDownList to a panel only when user clicks button "Add New", and add an event handler CheckedChanged to this control.

I also want to have the viewstate of every dropdownlist i have already added in order to use it when user clicks "Submit" (another button).

I figured out that the solution is ( according to lifecycle of aspx page ) :

PageInit 

if (Session["countDDL"] == null)
                Session["countDDL"] = 0;
            Session["countDDL"] = int.Parse(Session["countDDL"].ToString()) + 1;
             for (int i = 0; i < int.Parse(Session["countDDL"].ToString()); i++)
                {
                    DropDownList processes = new DropDownList();
                    ListItem lsi = new ListItem("Choose ");
                    processes.ID = "processes" + i.ToString();
                    processes.Width = 150;
                    processes.Items.Add(lsi);
                    processes.AutoPostBack = true;
                        FillList(processes);

                    processes.SelectedIndexChanged += new EventHandler(processes_SelectedIndexChanged);
                    pnlProcesses.Controls.Add(processes);
              }

Create and fill  all the dropdownlists that exist plus one more . The Viewstate works fine if the IDs are the same.

PageLoad

Session["buttonAddNewPressed"] = false;

Reset Session key.

protected void AddNewProcess_Click(object sender, ImageClickEventArgs e)
        {
            Session["buttonAddNewPressed"] = true;
        }

protected void Page_PreRender(object sender, EventArgs e)
        {
            if ((bool)Session["buttonAddNewPressed"] == false)
            {
                pnlProcesses.Controls.RemoveAt(pnlProcesses.Controls.Count -1);
                Session["countDDL"] = int.Parse(Session["countDDL"].ToString()) - 1;
            }
            
        }

If Button "Add New" didn't press i delete the last dropdownlist beacuse another event happened and decrease the session counter by one.

My question is " Can i make my code better ?" , i don't want to create and delete controls after . I decided to do this because the "Add New" Event fires between Page_Load and PreRender steps and the only way to create a control that its handlers are registered is to create before PreRender. So I create it at Init It could be in Page_Load as well and then if the button pressed i don't delete it.

Thanx in advance,

koraki_g

When I first started working with the Accordian control in an update Panel I had this issue. I was data binding a lot of things so as a result, I kept having to use a lot of caching in order to not over hit the database but also to retain the controls on the page. This is a pretty good way to do it from what I see. I need to figure out VB a bit more as I really only us C#.