Try to call the method "AttachTooltipForDropdowns" in pre_render event of dropdownlist. It worked for me.
protected void Page_InitComplete(object sender, EventArgs e)
{
drp.PreRender += new EventHandler(DropDown_PreRender);
}
public void DropDown_PreRender(object sender, EventArgs e)
{
DropDownList ddl = sender as DropDownList;
if (ddl != null)
{
foreach (ListItem li in ddl.Items)
{
li.Attributes.Add("title", li.Text);
}
}
}
{