how to pass a query string using a href inside gridview

<asp:TemplateField>
                <ItemTemplate>
                    <asp:HyperLink runat="server" ID="HyperLink1" NavigateUrl='<%# "yoururl.aspx?string1=" + Eval("value1")%>'
                        Text='click'></asp:HyperLink>
                </ItemTemplate>
            </asp:TemplateField>

<asp:templatefield headertext="Add Record" xmlns:asp="#unknown">
    <itemtemplate>
       <asp:linkbutton id="lbAdd" cssclass="link" runat="server" commandname="Add Record">
 CommandArgument='<%# Eval("SomeID")%>'>Edit</asp:linkbutton>
    </itemtemplate>
 </asp:templatefield>

//On RowCommand Try this
protected void gvStudent_RowCommand(object sender, GridViewCommandEventArgs e)
    {
        switch (e.CommandName)
        {
            case "Add Record":
                Server.Transfer(string.Format("YourPageName.aspx?ID={0}&mode=Add", Convert.ToString(e.CommandArgument)));
         break;
        }
}