In this articles describes how to visible Header columns in gridview. Here I have use ShowHeader Property to visible Header columns either true or false.
In client side(Default.aspx)
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false" DataKeyNames="Id" OnRowCommand="GridView1_RowCommand" BorderWidth="1px" ShowHeader="true">
</asp:GridView>