XML修改老是报错.正由另一进程使用，因此该进程无法访问该文件。

Question

每次执行读取后,再执行新增,然后执行修改,就会报错.
什么原因呢?
  /// <summary>
        /// 新增
        /// </summary>
        private void AddXmlInfo()
        {
            //忽略xml文件注释
            //忽略xml文件注释
            XmlDocument doc = new XmlDocument();
            //XmlReaderSettings xmlSetting = new XmlReaderSettings();
            // xmlSetting.IgnoreComments = true;
            //XmlReader xmlReader = XmlReader.Create(filePath, xmlSetting);
            doc.Load(filePath);
            XmlNode rootNode = doc.SelectSingleNode("LedList");            XmlElement ledElement = doc.CreateElement("Led");
            ledElement.SetAttribute("ScreenIndex", txtNewId.Text);
            XmlElement xWidth = doc.CreateElement("Width");
            xWidth.InnerText = txtWidth.Text;
            XmlElement xHeight = doc.CreateElement("Height");
            xHeight.InnerText = txtHeight.Text;
            XmlElement xIPAddress = doc.CreateElement("IPAddress");
            xIPAddress.InnerText = txtIpAddress.Text;
            XmlElement xIPPort = doc.CreateElement("IPPort");
            xIPPort.InnerText = txtPortNum.Text;
            XmlElement xSms = doc.CreateElement("Sms");
            xSms.SetAttribute("index", "0");
            ledElement.AppendChild(xWidth);
            ledElement.AppendChild(xHeight);
            ledElement.AppendChild(xIPAddress);
            ledElement.AppendChild(xIPPort);
            XmlElement xnX = doc.CreateElement("nX");
            xnX.InnerText = txtSendX.Text;
            XmlElement xnY = doc.CreateElement("nY");
            xnY.InnerText = txtSendY.Text;
            XmlElement xnW = doc.CreateElement("nW");
            xnW.InnerText = txtSendWidth.Text;
            XmlElement xnH = doc.CreateElement("nH");
            xnH.InnerText = txtSendHeight.Text;
            XmlElement xbFile = doc.CreateElement("bFile");
            xbFile.InnerText = "0";
            XmlElement xbDataType = doc.CreateElement("bDataType");
            xbDataType.InnerText = "0";
            XmlElement xchFontName = doc.CreateElement("chFontName");
            xchFontName.InnerText = txtSendFontName.Text;
            XmlElement xnFontNum = doc.CreateElement("nFontNum");
            xnFontNum.InnerText = txtSendFontSize.Text;
            XmlElement xnFontColor = doc.CreateElement("nFontColor");
            xnFontColor.InnerText = cmbSendColor.SelectedIndex.ToString();
            XmlElement xnActionType = doc.CreateElement("nActionType");
            xnActionType.InnerText = (cmbxSendShow.SelectedItem as ComListItem).Value.ToString();
            XmlElement xnActionSpeed = doc.CreateElement("nActionSpeed");
            xnActionSpeed.InnerText = txtSendFontSize.Text;
            XmlElement xnStillTime = doc.CreateElement("nStillTime");
            xnStillTime.InnerText = txtSendStayTime.Text;
            xSms.AppendChild(xnX);
            xSms.AppendChild(xnY);
            xSms.AppendChild(xnW);
            xSms.AppendChild(xnH);
            xSms.AppendChild(xbFile);
            xSms.AppendChild(xbDataType);
            xSms.AppendChild(xchFontName);
            xSms.AppendChild(xnFontNum);
            xSms.AppendChild(xnFontColor);
            xSms.AppendChild(xnActionType);
            xSms.AppendChild(xnActionSpeed);
            xSms.AppendChild(xnStillTime);
            ledElement.AppendChild(xSms);
            rootNode.AppendChild(ledElement);
         //   xmlReader.Close();
            doc.Save(filePath);
           
        }
        /// <summary>
        /// 修改
        /// </summary>
        /// <param name="index"></param>
        private void UpdateXmlInfoByScreenIndex(string sindex)
        {
            //忽略xml文件注释
            XmlDocument doc = new XmlDocument();
            //XmlReaderSettings xmlSetting = new XmlReaderSettings();
            // xmlSetting.IgnoreComments = true;
            //XmlReader xmlReader = XmlReader.Create(filePath, xmlSetting);
            doc.Load(filePath);
            XmlNode rootNode = doc.SelectSingleNode("LedList");
            // StringBuilder sb = new StringBuilder();
            foreach (XmlNode node in rootNode.ChildNodes)
            {
                XmlElement xe = (XmlElement)node;
                string ScreenIndex = xe.GetAttribute("ScreenIndex");
                //屏幕1
                if (ScreenIndex.Equals(sindex))
                {
                    XmlNodeList nodelist = xe.ChildNodes;                    nodelist[0].InnerText = txtWidth.Text;
                    nodelist[1].InnerText = txtHeight.Text;
                    nodelist[2].InnerText = txtIpAddress.Text;
                    nodelist[3].InnerText = txtPortNum.Text;
                    //获取字幕1内容
                    XmlNodeList smsList1 = nodelist[4].ChildNodes;
                    smsList1[0].InnerText = txtSendX.Text;
                    smsList1[1].InnerText = txtSendY.Text;
                    smsList1[2].InnerText = txtSendWidth.Text;
                    smsList1[3].InnerText = txtSendHeight.Text;
                    smsList1[6].InnerText = txtSendFontName.Text;
                    smsList1[7].InnerText = txtSendFontSize.Text;
                    smsList1[8].InnerText = cmbSendColor.SelectedIndex.ToString();                   
                    //移动方式抓取
                    smsList1[9].InnerText = (cmbxSendShow.SelectedItem as ComListItem).Value.ToString();                    smsList1[10].InnerText = txtSendSpeed.Text;
                    smsList1[11].InnerText = txtSendStayTime.Text;
                }
            }
      
            doc.Save(filePath);
            
        }        /// <summary>
        ///  读取
        /// </summary>
        /// <param name="sindex"></param>
        private void LoadXmlInfoByScreenIndex(string sindex)
        {
            //忽略xml文件注释
            XmlDocument doc = new XmlDocument();
            //XmlReaderSettings xmlSetting = new XmlReaderSettings();
           // xmlSetting.IgnoreComments = true;
            //XmlReader xmlReader = XmlReader.Create(filePath, xmlSetting);
            doc.Load(filePath);
          
            XmlNode rootNode = doc.SelectSingleNode("LedList");
            // StringBuilder sb = new StringBuilder();
            foreach (XmlNode node in rootNode.ChildNodes)
            {
                XmlElement xe = (XmlElement)node;
                string ScreenIndex = xe.GetAttribute("ScreenIndex");
                //屏幕1
                if (ScreenIndex.Equals(sindex))
                {
                    XmlNodeList nodelist = xe.ChildNodes;                    txtWidth.Text = nodelist[0].InnerText;
                    txtHeight.Text = nodelist[1].InnerText;
                    txtIpAddress.Text = nodelist[2].InnerText;
                    txtPortNum.Text = nodelist[3].InnerText;
                    //获取字幕1内容
                    XmlNodeList smsList1 = nodelist[4].ChildNodes;
                    txtSendX.Text = smsList1[0].InnerText;
                    txtSendY.Text = smsList1[1].InnerText;
                    txtSendWidth.Text = smsList1[2].InnerText;
                    txtSendHeight.Text = smsList1[3].InnerText;
                    txtSendFontName.Text = smsList1[6].InnerText;
                    txtSendFontSize.Text = smsList1[7].InnerText;
                    cmbSendColor.SelectedIndex = Convert.ToInt32(smsList1[8].InnerText);
                    //移动方式抓取
                    for (int i = 0; i < cmbxSendShow.Items.Count; i++)
                    {
                        if ((cmbxSendShow.Items[i] as ComListItem).Value.ToString() == smsList1[9].InnerText)
                        {
                            cmbxSendShow.SelectedIndex = i;
                        }
                    }
                    txtSendSpeed.Text = smsList1[10].InnerText;
                    txtSendStayTime.Text = smsList1[11].InnerText;
                }
            }

Answer 1

没有用到多线程??这是why??
<?xml version="1.0" encoding="utf-8"?>
<LedList>
  <Led ScreenIndex="1">
    <Width>64</Width>
    <Height>32</Height>
    <IPAddress>192.168.2.34</IPAddress>
    <IPPort>5005</IPPort>
    <Sms index="0">
      <nX>0</nX>
      <nY>0</nY>
      <nW>64</nW>
      <nH>16</nH>
      <bFile>0</bFile>
      <bDataType>0</bDataType>
      <chFontName>宋体</chFontName>
      <nFontNum>12</nFontNum>
      <nFontColor>1</nFontColor>
      <nActionType>3</nActionType>
      <nActionSpeed>12</nActionSpeed>
      <nStillTime>0</nStillTime>
    </Sms>
  </Led>
  <Led ScreenIndex="2">
    <Width>64</Width>
    <Height>32</Height>
    <IPAddress>192.168.2.34</IPAddress>
    <IPPort>5005</IPPort>
    <Sms index="0">
      <nX>0</nX>
      <nY>0</nY>
      <nW>64</nW>
      <nH>16</nH>
      <bFile>0</bFile>
      <bDataType>0</bDataType>
      <chFontName>宋体</chFontName>
      <nFontNum>12</nFontNum>
      <nFontColor>1</nFontColor>
      <nActionType>3</nActionType>
      <nActionSpeed>12</nActionSpeed>
      <nStillTime>0</nStillTime>
    </Sms>
  </Led>

Answer 2

xmlDocument没有提供释放方法的

Answer 3

你每次读取、增加、更新后把对象doc清空试试，也就是加上
doc = null;

Answer 4

找到了.
法克
    /// <summary>
        /// 绑定屏幕总数及序号
        /// </summary>
        private void BindDDlScreenIndex()
        {            string filePath = Process.GetCurrentProcess().MainModule.FileName;
            filePath = filePath.Substring(0, filePath.LastIndexOf("\\") + 1) + "LedConfig.xml";
            cmbScreen.Items.Clear();
            XmlReaderSettings setting = new XmlReaderSettings();
            setting.IgnoreComments = true;
            XmlReader xReader = XmlReader.Create(filePath, setting);
            XmlDocument doc = new XmlDocument();
            doc.Load(xReader);
            XmlNode ledNodes = doc.SelectSingleNode("LedList");
            foreach (XmlNode node in ledNodes)
            {
                string screenIndex = (node as XmlElement).GetAttribute("ScreenIndex");
                cmbScreen.Items.Add(new ComListItem(screenIndex, "屏幕" + screenIndex));
            }
            xReader.Close();
        }这边reader忘记close了!!!

Answer 5

下面列出微软.net类库提供的读写xml文件个类及其特点：
类名称 优点 缺点 
XmlReader 快速、高效、可扩展 只读，只向前，需要人工验证 
XmlDocument 可往返、可读写、支持XPath筛选 比XmlReader慢 
XPathNavigator 可往返，支持XPath和XSLT 只读 
XPathDocument 比XmlDocument，优化支持XPath和XSLT 比XmlReader慢 
本文提到的XmlReader也是微软类库中的一个类，它的特点是快速高效，并且可扩展，缺点是只读。