Jame Baond
New Member
I have created some Dynamic Controls(CheckBoxes) which are working fine and I am even able to retrieve the text value of the controls. But if i leave the page idle for about 30-45 mins and if I refresh the page or try check the CheckBoxes(Autopostback is set to true) for some rare reason i'm getting this following error. <BR>Object reference not set to an instance of an object.<BR>and pointing to the statement shown in red color.<BR>Has anybody got idea about this problem.<BR>Thanks in Advance <BR><BR>here's my code <BR><BR> private void Page_Load(object sender, System.EventArgs e)<BR> {<BR> foreach(CheckBox c1 in _checkboxes) <BR> { <BR> if (c1.Checked) <BR> { <BR> string strstore = c1.Text+ " "; <BR> strstorecb = strstorecb + strstore;<BR> } <BR> }<BR> if(!IsPostBack)<BR> {<BR> BindData();<BR> get_servc();<BR> }<BR>}<BR><BR> private void Page_PreRender(object sender, EventArgs e) <BR> { <BR> Session.Add ("CheckBoxArray", _checkboxes); <BR> }<BR><BR> #region Web Form Designer generated code<BR> override protected void OnInit(EventArgs e)<BR> {<BR> //<BR> // CODEGEN: This call is required by the ASP.NET Web Form Designer.<BR> //<BR> InitializeComponent();<BR> base.OnInit(e);<BR> if (Page.IsPostBack) <BR> _checkboxes = (ArrayList) Session["CheckBoxArray"]; <BR> else <BR> _checkboxes = new ArrayList(); <BR> <BR> foreach(CheckBox c1 in _checkboxes) <BR> Panel1.Controls.Add(c1); <BR> }The problem is not in the dynamic control initialization, the problem is that you're attempting to populate it based on a session value, which 45 minutes later has long since timed out and gone away. You're going to need to find somewhere else to store it, like a database, or ViewState.