C# dropdownlist change event

<asp:DropDownList runat="server" ID="myListDropDown" CssClass="text" OnSelectedIndexChanged="myListDropDown_Change" />

There's the aspx above

protected void myListDropDown_Change(object sender, EventArgs e)
        {
            //stuff that never gets hit
        }

I put a break point on the myListDropDown method but it never gets hit. Any suggestions?