xml去除指定节点，保留子节点操作

现有xml文件：

<?xml version="1.0" encoding="utf-8" ?>
<ShiftConfig xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
    <Ot>
        <BeforeOtRange>
            <Start>
                <DateTime xsi:nil="true" />
            </Start>
            <End>
                <DateTime xsi:nil="true" />
            </End>
            <StartPoint></StartPoint>
        </BeforeOtRange>
        <HolidayWorkingType>
            <Start>
                <DateTime xsi:nil="true" />
            </Start>
            <End>
                <DateTime xsi:nil="true" />
            </End>
            <StartPoint></StartPoint>
        </HolidayWorkingType>
        <AfterOtRange>
            <Start>
                <DateTime xsi:nil="true" />
            </Start>
            <End>
                <DateTime xsi:nil="true" />
            </End>
            <StartPoint></StartPoint>
        </AfterOtRange>
        <OvernightIn xsi:nil="true" />
        <OvernightOut xsi:nil="true" />
        <OvernightDayCount></OvernightDayCount>
        <TimeScale></TimeScale>
        <TimeScaleType></TimeScaleType>
        <IsAutoSwitchToOt>false</IsAutoSwitchToOt>
        <SwitchType>-</SwitchType>
        <IsSwitchTypeAfter>false</IsSwitchTypeAfter>
        <IsSwitchTypeMiddle>false</IsSwitchTypeMiddle>
        <IsSwitchTypeBefore>false</IsSwitchTypeBefore>
        <EffectiveMonth></EffectiveMonth>
        <IsSwitchToHoliday>false</IsSwitchToHoliday>
        <Boundary xsi:nil="true" />
    </Ot>
    <Item>
        <IsHolidayWorkingType>false</IsHolidayWorkingType>
        <ClockInInterval xsi:nil="true" />
        <WorkingHoursType></WorkingHoursType>
        <WorkingHours>--01T00::</WorkingHours>
        <EffectiveWorkingHours>--01T00::</EffectiveWorkingHours>
        <WorkingDays></WorkingDays>
        <IsNoAbsence>false</IsNoAbsence>
        <LatePoint></LatePoint>
        <LateBoundary xsi:nil="true" />
        <LeaveEarlyPoint></LeaveEarlyPoint>
        <LeaveEarlyBoundary xsi:nil="true" />
        <WorkingHoursTimeScale></WorkingHoursTimeScale>
        <MealMinuteCount></MealMinuteCount>
        <SecondDayWorkingLazy xsi:nil="true" />
        <MorningHalfDayStartDate>--01T00::</MorningHalfDayStartDate>
        <MorningHalfDayEndDate>--01T00::</MorningHalfDayEndDate>
        <AfterHalfDayStartDate>--01T00::</AfterHalfDayStartDate>
        <AfterHalfDayEndDate>--01T00::</AfterHalfDayEndDate>
        <LateAsAbsenteeismDate xsi:nil="true" />
        <LeaveEarlyAsAbsenteeismDate xsi:nil="true" />
        <IsLackSwingCard>false</IsLackSwingCard>
        <DaysOfLackSwingCardAsabsenteeism></DaysOfLackSwingCardAsabsenteeism>
        <Priority></Priority>
        <IsToLateOrEarlyFromHalfDayOfAbsence>false</IsToLateOrEarlyFromHalfDayOfAbsence>
        <YesterdayStart>--01T00::+:</YesterdayStart>
    </Item>
</ShiftConfig>

我要去除Ot与Item节点：

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Xml;
using System.Web;
namespace ConsoleApplicationXml
{
    class Program
    {
        static void Main(string[] args)
        {
            //string xmlFilePath = @"X:\about.net\example\XmlExample\1.xml";
            //string xmlFilePath = HttpContext.Current.Server.MapPath("ShiftConfig.xml");
            //StringBuilder sb = new StringBuilder();
            if (File.Exists("ShiftConfig.xml") == true)
            {
                string xmlValue = "";
                string xmlString = File.ReadAllText("ShiftConfig.xml");
                XmlDocument xmlDoc = new XmlDocument();
                xmlDoc.LoadXml(xmlString);
                XmlNode root = xmlDoc.DocumentElement;     //取到根结点
                XmlNode otNode = xmlDoc.SelectSingleNode("ShiftConfig/Ot");
                XmlNode itemNode = xmlDoc.SelectSingleNode("ShiftConfig/Item");
                if (otNode != null)
                {
                    XmlNodeList otNodeList = otNode.ChildNodes;
                    if (otNodeList != null)
                    {
                        foreach (XmlNode xn in otNodeList)
                        {
                            XmlNode deep = xn.CloneNode(true); //克隆根节点
                            XmlNode xx = xmlDoc.ImportNode(deep, true);
                            root.AppendChild(xx);
                        }
                        root.RemoveChild(otNode);
                    }
                }
                if (itemNode != null)
                {
                    XmlNodeList itemNodeList = itemNode.ChildNodes;
                    if (itemNodeList != null)
                    {
                        foreach (XmlNode xn in itemNodeList)
                        {
                            XmlNode deep = xn.CloneNode(true); //克隆根节点
                            XmlNode xx = xmlDoc.ImportNode(deep, true);
                            root.AppendChild(xx);
                        }
                        root.RemoveChild(itemNode);
                    }
                }

                if (otNode != null || itemNode != null)
                {
                    MemoryStream stream = new MemoryStream();
                    XmlTextWriter writer = new XmlTextWriter(stream, null);
                    writer.Formatting = Formatting.Indented;
                    xmlDoc.Save(writer);
                    StreamReader streamReader = new StreamReader(stream, System.Text.Encoding.UTF8);
                    stream.Position = ;
                    xmlValue = streamReader.ReadToEnd();
                    streamReader.Close();
                    stream.Close();
                }

                Console.WriteLine(xmlValue);

                //if (otNodeList != null)
                //{
                //    foreach (XmlNode xn in otNodeList)
                //    {
                //        XmlElement xe = (XmlElement)xn;//将子节点类型转换为XmlElement类型
                //        //if (xe.Name == "BeforeOtRange")//如果找到
                //        //{
                //        //
                //        //}
                //        sb.Append("" + xe.OuterXml + "");
                //    }
                //}
                //if (itemNodeList != null)
                //{
                //    //TODO:把item下面的节点foreach
                //    foreach (XmlNode xn in itemNodeList)
                //    {
                //        XmlElement xe = (XmlElement)xn;//将子节点类型转换为XmlElement类型
                //        sb.Append("" + xe.OuterXml + "");
                //    }
                //}
                //root.InnerXml = sb.ToString();

                xmlDoc.Save("D:\\xmloperate\\ConsoleApplicationXml\\ShiftConfig.xml");
                //Console.WriteLine(sb.ToString());
                //Console.WriteLine(root);

                Console.Write("\r\nPress any key to continue....");
                Console.Read();
            }

        }
    }
}