The list items in a drop down list does not have a tool tip property and many time dues to space constraint we need to specify the width of a drop down and some items have text length greater than the width. In this case we can show a tooltip for that item displaying its text property as a tooltip.
I have created an extension method for the drop down list.
public static void SetToolTip(this DropDownList cmb)
if (cmb.Items.Count > 0)
foreach (ListItem item in cmb.Items)
Just call it after calling DataBind()