使用linq从XML文档中删除最近30天的节点

Question

I have XML Document like

 <Records>
   <Record>
    <Event>Home Value Submits Page 2</Event>
    <Date>17-Mar-14 4:49:32 PM</Date>
   </Record>
   <Record>
    <Event>Hm Value Submits Hm Pg</Event>
    <Date>17-Mar-14 4:54:36 PM</Date>
   </Record>
 </Records>

I need to delete last 30 Days nodes from XML Document.

I am using this code but it's not working,

var xelement = XElement.Load(Server.MapPath("~/XMLStorage/DataBase.xml"));
var value30days =
    from nm in xelement.Elements("Record")
    where (DateTime)nm.Element("Date") <= DateTime.Now && (DateTime)nm.Element("Date") >= DateTime.Now.AddDays(-30)
    select nm;

foreach (XElement xEle in value30days)
{
    xEle.Remove();
}

xelement.Save(Server.MapPath("~/XMLStorage/DataBase.xml"));

Please Give some solutions.

Answer 1

This is one of those fun problems caused by changing a collection while enumerating/querying it. As soon as you try to remove the first item you break the query.

Try this:

    foreach (XElement xEle in value30days.ToArray())
    {
        xEle.Remove();
    }

The ToArray call will ensure that the entire set of results is returned before you start modifying the XML content. You can then iterate through the array and delete as many of those items as you like without the loop breaking.