asp.net - 日期时间（月+年）与字符串比较

Question

我有一个 TextBox 和 Extender AjaxCalander。选择日期时，它的工作正常，仅在 TextBox 中显示月份和年份。我的代码如下

 <asp:TextBox ID="txtCardExpiry" runat="server" Width="200px" /><span> MMYY</span>
 <ajaxToolkit:CalendarExtender runat="server" Format="MMyy" TargetControlID="txtCardExpiry" />

我想验证信用卡是否未过期

现在我如何txtCardExpiry.Text与今天的月份和年份进行比较

现在我正在使用

 int dtNowYear = Convert.ToInt16(DateTime.Now.Year.ToString().Substring(2, 2));
            int dtNowMonth = Convert.ToInt16(DateTime.Now.Month.ToString());
            int dtExpYear = Convert.ToInt16(txtCardExpiry.Text.Substring(2, 2));
            int dtExpMonth = Convert.ToInt16(txtCardExpiry.Text.Substring(0, 2));

            if (dtNowYear == dtExpYear && dtNowMonth > dtExpMonth)
            {
                lblMessage.Attributes.Add("class", "lblMessageError");
                lblMessage.Text =
                    "Credit Card expiry month and year cannot be less than todays month and year or your Credit Card has expired";
                return false;
            }
                 else if (dtNowYear > dtExpYear) 
                {
                    if (dtNowMonth > dtExpMonth)
                    {
                        lblMessage.Attributes.Add("class", "lblMessageError");
                        lblMessage.Text =
                            "Credit Card expiry month and year cannot be less than todays month and year or your Credit Card has expired";
                        return false;
                    }
                    return false;
                } 

Answer 1

尝试

txtCardExpiry.Text.Compare(DateTime.Now.ToString("MMyyyy"))

自定义日期和时间格式字符串 必须说，MSDN 很有帮助。