提问人：Andrew Truckle 提问时间：9/12/2023 最后编辑：Andrew Truckle 更新时间：9/13/2023 访问量：37
在正确的位置添加 Linq to XML 的新条目（基于数值属性）
Adding a new entry with Linq to XML at the right position (based on numerical attribute)
问：
我想出了这个函数来保存或更新XML文件中的条目。
public void SetOutlineInfo(string talksdatabase, int talknumber, string languageCode, bool talkExcluded, DateTime dateExcudedFrom, string excludedNote)
{
try
{
XDocument doc = XDocument.Load(talksdatabase);
var ptLang = doc.Descendants(languageCode).FirstOrDefault();
if (ptLang != null)
{
var ptInfo = ptLang
.Descendants("PublicTalk")
.Where(p => p.Attribute("Number").Value == talknumber.ToString()).FirstOrDefault();
if (ptInfo != null)
{
ptInfo.Attribute("Excluded").Value = talkExcluded ? "true" : "false";
ptInfo.Attribute("ExcludedFromDate").Value = dateExcudedFrom.ToString("yyyy-MM-dd");
ptInfo.Attribute("ExcludedNote").Value = excludedNote;
}
else
{
ptLang.Add(new XElement("PublicTalk",
new XAttribute("Number", talknumber),
new XAttribute("Excluded", talkExcluded),
new XAttribute("ExcludedFromDate", dateExcudedFrom.ToString("yyyy-MM-dd")),
new XAttribute("ExcludedNote", excludedNote)
));
}
doc.Save(talksdatabase);
}
}
catch (Exception ex)
{
SimpleLog.Log(ex);
}
}
唯一的问题是添加新条目不会将其添加到正确的数字位置（属性）。Number
我做了一些搜索，它们都显示阅读记录并使用 .但我在写记录。orderby
按照评论中的要求。
下面是一个 XML：
<?xml version="1.0" encoding="utf-8"?>
<PublicTalkTitles>
<eng>
<PublicTalk Number="47" Excluded="true" ExcludedFromDate="2019-04-01" ExcludedNote="S-147 19.03" />
</eng>
</PublicTalkTitles>
当添加一个新条目时，说谈话编号 1：
<?xml version="1.0" encoding="utf-8"?>
<PublicTalkTitles>
<eng>
<PublicTalk Number="1" Excluded="true" ExcludedFromDate="2023-09-12" ExcludedNote="1" />
<PublicTalk Number="47" Excluded="true" ExcludedFromDate="2019-04-01" ExcludedNote="S-147 19.03" />
</eng>
</PublicTalkTitles>
答：
0赞
Andrew Truckle
9/12/2023
#1
根据使用建议，我修改了该函数：AddBeforeSelf
public void SetOutlineInfo(string talksdatabase, int talknumber, string languageCode, bool talkExcluded, DateTime dateExcudedFrom, string excludedNote)
{
try
{
XDocument doc = XDocument.Load(talksdatabase);
var ptLang = doc.Descendants(languageCode).FirstOrDefault();
if (ptLang != null)
{
var ptInfo = ptLang
.Descendants("PublicTalk")
.Where(p => p.Attribute("Number").Value == talknumber.ToString()).FirstOrDefault();
if (ptInfo != null)
{
ptInfo.Attribute("Excluded").Value = talkExcluded ? "true" : "false";
ptInfo.Attribute("ExcludedFromDate").Value = dateExcudedFrom.ToString("yyyy-MM-dd");
ptInfo.Attribute("ExcludedNote").Value = excludedNote;
}
else
{
var ptList = ptLang.Descendants("PublicTalk");
bool bAdd = true;
foreach ( var pt in ptList )
{
if (Convert.ToInt32(pt.Attribute("Number").Value) > talknumber)
{
pt.AddBeforeSelf(new XElement("PublicTalk",
new XAttribute("Number", talknumber.ToString()),
new XAttribute("Excluded", talkExcluded),
new XAttribute("ExcludedFromDate", dateExcudedFrom.ToString("yyyy-MM-dd")),
new XAttribute("ExcludedNote", excludedNote)
));
bAdd = false;
break;
}
}
if(bAdd)
{
ptLang.Add(new XElement("PublicTalk",
new XAttribute("Number", talknumber.ToString()),
new XAttribute("Excluded", talkExcluded),
new XAttribute("ExcludedFromDate", dateExcudedFrom.ToString("yyyy-MM-dd")),
new XAttribute("ExcludedNote", excludedNote)
));
}
}
doc.Save(talksdatabase);
}
}
catch (Exception ex)
{
SimpleLog.Log(ex);
}
}
1赞
Charlieface
9/13/2023
#2
您需要首先过滤所有节点，然后采用该数字。您需要将其解析为 an 才能正确进行此过滤和排序。<= talknumberMaxByint
那么该节点是：
- 你想要的那个
- 改变它
- 或之前的那个
- 用
AddBeforeSelf
- 用
- 或 null
- 在父母身上使用。
AddFirst
- 在父母身上使用。
var ptLang = doc.Element("PublicTalkTitles").Element(languageCode);
if (ptLang != null)
{
var pt = ptLang.Elements("PublicTalk");
var ptInfo = pt
.Where(p => int.Parse(p.Attribute("Number").Value) <= talknumber)
.MaxBy(p => int.Parse(p.Attribute("Number").Value));
if (int.Parse(ptInfo?.Attribute("Number").Value ?? "0") == talknumber)
{
ptInfo.Attribute("Excluded").Value = talkExcluded ? "true" : "false";
ptInfo.Attribute("ExcludedFromDate").Value = dateExcudedFrom.ToString("yyyy-MM-dd");
ptInfo.Attribute("ExcludedNote").Value = excludedNote;
}
else
{
var newElem = new XElement("PublicTalk",
new XAttribute("Number", talknumber),
new XAttribute("Excluded", talkExcluded),
new XAttribute("ExcludedFromDate", dateExcudedFrom.ToString("yyyy-MM-dd")),
new XAttribute("ExcludedNote", excludedNote)
);
if (ptInfo != null)
ptInfo.AddAfterSelf(newElem);
else
ptLang.AddFirst(newElem);
}
}
如果你没有，你可以改用效率较低的方法。MaxByOrderByDescending.FirstOrDefault
var ptInfo = pt
.Where(p => int.Parse(p.Attribute("Number").Value) <= talknumber)
.OrderByDescending(p => int.Parse(p.Attribute("Number").Value))
.FirstOrDefault();
评论
0赞
Andrew Truckle
9/13/2023
谢谢。我收到一个语法错误，告诉我我无法使用。我正在使用框架 4.6.2，目前无法更改它。MaxBy
1赞
Charlieface
9/13/2023
好的，你可以使用，见编辑OrderByDescending
0赞
Andrew Truckle
9/13/2023
谢谢;我只是将Visual Studio升级到最新版本，然后我将尝试此调整后的代码。
评论