WdatePicker 设置时间范围在某个时间段

txtdt.Attributes.Add("onclick", "WdatePicker({dateFmt:'yyyy-MM-dd',lang:'zh-cn',minDate: '#F{$dp.$D(\'" + maxdt.ClientID + "\',{d:" + -dates + "});}',maxDate:'#F{$dp.$D(\'" + maxdt.ClientID + "\')}'})");
                                    maxdt.Attributes.Add("onclick", "WdatePicker({dateFmt:'yyyy-MM-dd',lang:'zh-cn'},minDate: '#F{$dp.$D(\'" + txtdt.ClientID + "\');}',maxDate:'#F{$dp.$D(\'" + txtdt.ClientID + "\'),{d:" + dates + "}}')");