GridView 对于长字段省略显示

代码：

    <asp:GridView ID="gvO" runat="server" AllowPaging="True" AutoGenerateColumns="False"

        AllowSorting="True" Width="1080px" PageSize="20">

        <Columns>

            <asp:TemplateField HeaderText="工程名称">

                <ItemTemplate>

                    <asp:Label ID="labProject_Name" runat="server" Width="100%" Text='<%# Convert.ToString(Eval("project_name_c")).Length>12?Convert.ToString(Eval("project_name_c")).Substring(0,12)+".":Eval("project_name_c") %>'

                        ToolTip='<%# Eval("project_name_c") %>'></asp:Label>

                </ItemTemplate>

            </asp:TemplateField>

        </Columns>

    </asp:GridView>