Databinding methods such as Eval(), XPath(), and Bind() can only be used in the cont

when i try to bind the data in the drop down list i am getting the above error. here is the code

<asp:DropDownList ID="DropDownList3" runat="server"
Style="left: 380px; position: absolute;top: 48px; z-index: 112; width: 216px;" SelectedValue='<%# Bind("category") %>'
DataSourceID="SqlDataSource3" DataTextField="category" DataValueField="category">
</asp:DropDownList>

Thanks for the help