Error: Data Not show in asp.net dropdown from sharepointList

Question

I Write that code on page load of visual webpart

 

if (!Page.IsPostBack)

{

using (SPSite site = new SPSite("http://spserver:1500"))

{

using (SPWeb web = site.OpenWeb())

{

web.AllowUnsafeUpdates = true;

SPList list = web.Lists["questionslist"];

ddlsecurity.DataSource = list.Items;

ddlsecurity.DataValueField = "Title"; // List field holding value - first column is called Title anyway!

ddlsecurity.DataTextField = "Title"; // List field holding name to be displayed on page

ddlsecurity.DataBind();

ddlsecurity.Items.Insert(0, new ListItem("--Select--", ""));

}

}

}