hide a text with read more link

i have  made that  but  it doesnt work
<form id="form1" runat="server"> <div> <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" DataSourceID="SqlDataSource1" > <Columns> <asp:BoundField DataField="comments" HeaderText="comments" SortExpression="comments" /> </Columns> <EmptyDataTemplate> <asp:Label ID="lblDescription" runat="server" Text='<%# Limit(Eval("comments"), 10)%>' Tooltip='<%# Eval("comments")%>'></asp:Label> <br /> <br /> <asp:LinkButton ID="ReadMoreLinkButton" runat="server" Text="Read more" Visible='<%# SetVisibility(Eval("comments"), 10) %>' OnClick="ReadMoreLinkButton_Click"></asp:LinkButton> </EmptyDataTemplate> </asp:GridView> <asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:DATABASEConnectionString %>" SelectCommand= ...