Question

XML

<CalendarFairs> 
    <CalendarFair>
        <DateStart>2011-04-05T00:00:00</DateStart>
       <DateEnd>2011-04-09T00:00:00</DateEnd>
        <Title>aaaa</Title>   
       <IdExecutive>1</IdExecutive>
   </CalendarFair>
  <CalendarFair>
      <DateStart>2011-04-16T00:00:00</DateStart>
      <DateEnd>2011-04-19T00:00:00</DateEnd>
      <Title>bbb</Title>
      <IdExecutive>2</IdExecutive>
  </CalendarFair>
<CalendarFairs>

代码

  var elements = from element in doc.Descendants("CalendarFair")
                           where DateTime.Parse (element.Elements ("DateStart").ToString())==DateTime.Now 
                           select new
                           {
                               dateStart = element.Element("DateStart").Value,
                               dateEnd=element.Element("DateEnd").Value,
                               title=element.Element("Title").Value,
                               idExcutive = element.Element("IdExecutive").Value ,
                           };

foreach (var item in elements)//send this error

            {}
System.FormatException: The string was not recognized as a valid DateTime. There is a 
unknown word starting at index 0.

为什么会出错？

Answer 1

尝试按如下方式更改它：

var elements = from element in doc.Descendants("CalendarFair")
               let start = element.Element("DateStart").Value
               where DateTime.Parse (start)==DateTime.Now.Date
               select new
               {
                   dateStart = start,
                   dateEnd=element.Element("DateEnd").Value,
                   title=element.Element("Title").Value,
                   idExcutive = element.Element("IdExecutive").Value ,
               };

编辑：根据您发布的XML，上面的查询效果非常好。尝试使用此输入进行测试：

<CalendarFairs> 
    <CalendarFair>
        <DateStart>2011-04-05T00:00:00</DateStart>
       <DateEnd>2011-04-09T00:00:00</DateEnd>
        <Title>aaaa</Title>   
       <IdExecutive>1</IdExecutive>
   </CalendarFair>
  <CalendarFair>
      <DateStart>2011-03-20T00:00:00</DateStart>
      <DateEnd>2011-04-19T00:00:00</DateEnd>
      <Title>bbb</Title>
      <IdExecutive>2</IdExecutive>
  </CalendarFair>
</CalendarFairs>

请注意，我已插入今天的开始日期。实际上我认为结果是空的只是因为没有具有实际日期的条目。

Answer 2

听起来您的一个或多个输入<DateStart>字符串不是有效的DateTime格式。

您可以发布一些示例输入XML吗？

您可能需要使用ParseExact提供日期格式 - http://msdn.microsoft.com/en-us/library/w2sa9yss.aspx

xml和条件by dateTime

2 个答案: