asp.net c#

 <input id="Button1" class="button" style="position: relative" type="button" value="回上一页"  onclick="window.history.back()"/>
            </FooterTemplate>
            <Fields>
                <asp:BoundField DataField="bh" HeaderText="编号" ReadOnly="True" SortExpression="bh" />
                <asp:BoundField DataField="ISDN" HeaderText="ISDN" SortExpression="ISDN" />
                <asp:BoundField DataField="Bookname" HeaderText="书名" SortExpression="Bookname" />
                <asp:BoundField DataField="typename" HeaderText="类型" SortExpression="typename" />
                <asp:BoundField DataField="press" HeaderText="出版社" SortExpression="press" />
                <asp:BoundField DataField="cbdate" HeaderText="出版日期" SortExpression="cbdate" />
                <asp:BoundField DataField="author" HeaderText="作者" SortExpression="author" />
                <asp:BoundField DataField="price" HeaderText="价格" SortExpression="price" />
                <asp:TemplateField HeaderText="内容" SortExpression="Bookname">
                    <ItemTemplate>
                        <asp:Label ID="Label1" runat="server" Style="position: relative" Text='<%# Replace(Eval("bookname"),vbcrlf,"<br>") %>'></asp:Label>                    </ItemTemplate>
                </asp:TemplateField>
            </Fields>
            <HeaderStyle BackColor="#4A3C8C" Font-Bold="True" ForeColor="#F7F7F7" />
            <EditRowStyle BackColor="#738A9C" Font-Bold="True" ForeColor="#F7F7F7" />
            <AlternatingRowStyle BackColor="#F7F7F7" CssClass="row2" />
        </asp:DetailsView>
    </div>
    </form>
</body>
</html>
错误 1 当前上下文中不存在名称“Replace” F:\网站\图书公告\book.aspx 42 那行红色的有问题？请问怎么解决啊》？