form id="form1" runat="server">
        <div style="text-align:center">验证范围控件
        <hr style="width:50%"/>
        旅游登记信息<br />
         客户编号：
         <asp:TextBox ID="num_id" runat="server" BackColor="White"></asp:TextBox>
         <asp:RangeValidator ID="RangeValidator1" runat="server" ErrorMessage="编号为1~1000之间"
            ControlToValidate="num_id" MaximumValue="1000" MinimumValue="1" Type="Integer"></asp:RangeValidator><br />
            旅游日期：
            <asp:TextBox ID="travel_date" runat="server"></asp:TextBox>
            <asp:RangeValidator    runat="server" ID="RangeValidator2" ErrorMessage="旅游日期为2个月内" 
            ControlToValidate="travel_date" Type="Date">
            </asp:RangeValidator><br/>
            <asp:Button ID="Button1" runat="server" Text="提交" OnClick="button_Click" /><br />
            <asp:Label ID="Label1" runat="server" Width="353px" ForeColor="Red"></asp:Label>
        </div>
        </form>

 protected void Page_Load(object sender, EventArgs e)
                {
                        RangeValidator2.MinimumValue = DateTime.Now.ToShortDateString();
                        RangeValidator2.MaximumValue = DateTime.Now.AddMonths(2).ToShortDateString();//这里是学习的重点，addmonths（）为从目前加上几个月为止，也可以是年
                }

                protected void button_Click(object sender, EventArgs e)
                {
                        //验证提示
                        if (Page.IsValid) 
                        Label1.Text = "验证成功";
                }