Exporting to Excel GridView only

I have a GridView in my Content page along with some DropDownList which I use for filtering:
<asp:Panel ID="pnlDropDown" runat="server" ClientIDMode="Static" CssClass="pnlDropDown"> <!-- TASK NAME --> <asp:DropDownList ID="ddlTaskName" CssClass="chosen-select" DataSourceID="dsPopulateTaskName" AutoPostBack="true" DataValueField="Task Name" runat="server" Width="100%" Font-Size="11px" AppendDataBoundItems="true" OnSelectedIndexChanged="ddlTaskName_onSelectIndexChanged"> <asp:ListItem Text="All" Value="%"></asp:ListItem> </asp:DropDownList> <asp:SqlDataSource ID="dsPopulateTaskName" runat="server" ConnectionString="<%$ ConnectionStrings:gvConnString %>" SelectCommand="&qu ...