ConditionExpression's ConditionOperator For Datetime

对于ConditionExpression中用到Datetime类型匹配，尝试了N种方法，终于找到了合适的解决方案；

new ConditionExpression("gf_establishdate",ConditionOperator.GreaterEqual,(new DateTime(fromYear,fromMonth,fromDay)).ToUniversalTime().ToString())
,new ConditionExpression("gf_establishdate",ConditionOperator.LessEqual,(new DateTime(toYear,toMonth,toDay)).ToUniversalTime().ToString() )

ConditionOperator.GreaterEqual 太于等于

ConditionOperator.LessEqual 小于等于