DropDownList's SelectedIndexChanged event not firing

Set DropDownList AutoPostBack property to true.

Eg:

<asp:DropDownList ID="logList" runat="server" AutoPostBack="True" 
        onselectedindexchanged="itemSelected">
    </asp:DropDownList>

try setting AutoPostBack="True" on the DropDownList.

I know its bit older post, but still i would like to add up something to the answers above.

There might be some situation where in, the "value" of more than one items in the dropdown list is duplicated/same. So, make sure that you have no repeated values in the list items to trigger this "onselectedindexchanged" event