div的流式布局 环循读出label

<%
                if (_list != null)
                {
                    int n = 0;
                    foreach (string deptName in _list)
                    {
                        n++;
                        Label1.Text = deptName;
            %>
        <div style="width:270px;float:left" >
         <asp:CheckBox ID="CheckBox1" runat="server" />
        <asp:Label ID="Label1" runat="server">ffff</asp:Label></div>
            <%
                    if (n == 4 || n == 8 || n == 12 || n == 16 || n == 20)
                    { 
                        %>
                            <br />
                        
                        <%
                    } 
                        
                }
            }
             %>

<div style="width:270px;float:left" >   div的流式布局
环循读出label