LINQ和XDocument:如何创建XML文件？

Question

我在c#中有一个三个List,变量名是l_lstData1, l_lstData2, l_lstData3.

文件结构是

<FileDetails>  
  <Date FileModified="29/04/2010 12:34:02" />   
  <Data Name="Data_1" DataList="India" Level="2" />   
  <Data Name="Data_2" DataList="chennai" Level="2" />   
  <Data Name="Data_3" DataList="hyderabad" Level="2" />   
  <Data Name="Data_4" DataList="calcutta" Level="2" />  
  <Data Name="Data_5" DataList="vijayawada" Level="1" /> 
  <Data Name="Data_6" DataList="cochin" Level="1" /> 
  <Data Name="Data_7" DataList="madurai" Level="0" />  
  <Data Name="Data_8" DataList="trichy" Level="0" />   
</FileDetails>

3个列表的值如下:

 l_lstData1[0] = "India";
 l_lstData1[1] = "chennai";
 l_lstData1[2] = "hyderabad";
 l_lstData1[3] = "calcutta"; 

所以上面的XML(element:Data)的level属性值="2".

 l_lstData2[0] = "vijayawada";
 l_lstData2[1] = "cochin";      

所以上面的XML(element:Data)的level属性值="1".

 l_lstData3[0] = "madurai";
 l_lstData3[1] = "trichy";      

所以上面的XML(element:Data)的level属性值为"0".

Answer 1

目前还不清楚为什么 "Level"属性是如此指定的,但这会为您创建相关的XML:

// Used for side-effects in the XElement constructor. This is a bit icky. It's
// not clear what the "Name" part is really for...
int count = 1;

var doc = new XDocument(
    new XElement("FileDetails",
        new XElement("Date", new XAttribute("FileModified", DateTime.UtcNow)),
        l_lstData1.Select(x => new XElement("Data",
            new XAttribute("Name", "Data_" + count++),
            new XAttribute("DataList", x),
            new XAttribute("Level", 2))),
        l_lstData2.Select(x => new XElement("Data",
            new XAttribute("Name", "Data_" + count++),
            new XAttribute("DataList", x),
            new XAttribute("Level", 1))),
        l_lstData3.Select(x => new XElement("Data",
            new XAttribute("Name", "Data_" + count++),
            new XAttribute("DataList", x),
            new XAttribute("Level", 0)))));

如果你可以将列表项中的投影提取到它的元素,那么它可能会更简洁,但是这"Data_" + count一点很棘手.目前尚不清楚为什么你需要这样的事情才能说实话......如果没有它可以逃脱,代码可能更清晰.

我想一个替代方案是创建该文件没有的Name属性,然后填充它们之后.例如:

private static IEnumerable<XElement> ProjectList(IEnumerable<string> list,
    int level)
{
    return list.Select(x => new XElement("Data",
        new XAttribute("DataList", x),
        new XAttribute("Level", level)));
}

然后:

var doc = new XDocument(
    new XElement("FileDetails",
        new XElement("Date", new XAttribute("FileModified", DateTime.UtcNow)),
        ProjectList(l_lstData1, 2),
        ProjectList(l_lstData2, 1),
        ProjectList(l_lstData3, 0)));

int count = 1;
foreach (var element in doc.Descendants("Data"))
{
    element.SetAttributeValue("Name", "Data_" + count++);
}