How to insert a DropDownList inside the GridView's first header

I have the following ASP.net page which displays a table with some DropDownList and right underneath another table (GridView) with the data which will be filtered through the DropDownLiad from the first table:
<table class="taskGridView" runat="server"> <tr> <td> <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> < ...