C#操作XML的通用方法總結

    在.net的項目開發中，經常會對XML文件進行操作，由於XML文件可以實現跨平臺傳輸，較多的應用在數據傳輸中，特總結以下幾種常用的XML操作方法：

1.創建XML文檔：

        /// <summary>
        /// 創建XML文檔
        /// </summary>
        /// <param name="name">根節點名稱</param>
        /// <param name="type">根節點的一個屬性值</param>
        /// <returns>XmlDocument對象</returns>     
        public static XmlDocument CreateXmlDocument(string name, string type)
        {
            XmlDocument doc;
            try
            {
                doc = new XmlDocument();
                doc.LoadXml("<" + name + "/>");
                var rootEle = doc.DocumentElement;
                rootEle?.SetAttribute("type", type);
            }
            catch (Exception er)
            {
                throw new Exception(er.ToString());
            }
            return doc;
        }

2.讀取XML文檔中的數據：

        /// <summary>
        /// 讀取數據
        /// </summary>
        /// <param name="path">路徑</param>
        /// <param name="node">節點</param>
        /// <param name="attribute">屬性名，非空時返回該屬性值，否則返回串聯值</param>
        /// <returns>string</returns>
        public static string Read(string path, string node, string attribute)
        {
            var value = "";
            try
            {
                var doc = new XmlDocument();
                doc.Load(path);
                var xn = doc.SelectSingleNode(node);
                if (xn != null && xn.Attributes != null)
                    value = (attribute.Equals("") ? xn.InnerText : xn.Attributes[attribute].Value);
            }
            catch (Exception er)
            {
                throw new Exception(er.ToString());
            }
            return value;
        }

3.對XML文檔插入數據：

        /// <summary>
        /// 插入數據
        /// </summary>
        /// <param name="path">路徑</param>
        /// <param name="node">節點</param>
        /// <param name="element">元素名，非空時插入新元素，否則在該元素中插入屬性</param>
        /// <param name="attribute">屬性名，非空時插入該元素屬性值，否則插入元素值</param>
        /// <param name="value">值</param>
        /// <returns></returns>
        public static void Insert(string path, string node, string element, string attribute, string value)
        {
            try
            {
                var doc = new XmlDocument();
                doc.Load(path);
                var xn = doc.SelectSingleNode(node);
                if (element.Equals(""))
                {
                    if (!attribute.Equals(""))
                    {
                        var xe = (XmlElement)xn;
                        xe?.SetAttribute(attribute, value);
                        //xe?.SetAttribute(attribute, value);
                    }
                }
                else
                {
                    var xe = doc.CreateElement(element);
                    if (attribute.Equals(""))
                        xe.InnerText = value;
                    else
                        xe.SetAttribute(attribute, value);
                    xn?.AppendChild(xe);
                }
                doc.Save(path);
            }
            catch (Exception er)
            {
                throw new Exception(er.ToString());
            }
        }

4.修改XML文檔中的數據：

        /// <summary>
        /// 修改數據
        /// </summary>
        /// <param name="path">路徑</param>
        /// <param name="node">節點</param>
        /// <param name="attribute">屬性名，非空時修改該節點屬性值，否則修改節點值</param>
        /// <param name="value">值</param>
        /// <returns></returns>
        public static void Update(string path, string node, string attribute, string value)
        {
            try
            {
                var doc = new XmlDocument();
                doc.Load(path);
                var xn = doc.SelectSingleNode(node);
                var xe = (XmlElement)xn;
                if (attribute.Equals(""))
                {
                    if (xe != null) xe.InnerText = value;
                }
                else
                {
                    xe?.SetAttribute(attribute, value);
                }
                doc.Save(path);
            }
            catch (Exception er)
            {
                throw new Exception(er.ToString());
            }
        }

5.刪除XML文檔中數據：

        /// <summary>
        /// 刪除數據
        /// </summary>
        /// <param name="path">路徑</param>
        /// <param name="node">節點</param>
        /// <param name="attribute">屬性名，非空時刪除該節點屬性值，否則刪除節點值</param>
        /// <returns></returns>
        public static void Delete(string path, string node, string attribute)
        {
            try
            {
                var doc = new XmlDocument();
                doc.Load(path);
                var xn = doc.SelectSingleNode(node);
                var xe = (XmlElement)xn;
                if (attribute.Equals(""))
                {
                    xn?.ParentNode?.RemoveChild(xn);
                }
                else
                {
                    xe?.RemoveAttribute(attribute);
                }
                doc.Save(path);
            }
            catch (Exception er)
            {
                throw new Exception(er.ToString());
            }
        }

6.讀取XML文檔中指定節點數據：

        /// <summary>
        /// 獲得xml文件中指定節點的節點數據
        /// </summary>
        /// <param name="path"></param>
        /// <param name="nodeName"></param>
        /// <returns></returns>
        public static string GetNodeInfoByNodeName(string path, string nodeName)
        {
            var xmlString = string.Empty;
            try
            {
                var xml = new XmlDocument();
                xml.Load(path);
                var root = xml.DocumentElement;
                if (root == null) return xmlString;
                var node = root.SelectSingleNode("//" + nodeName);
                if (node != null)
                {
                    xmlString = node.InnerText;
                }
            }
            catch (Exception er)
            {
                throw new Exception(er.ToString());
            }
            return xmlString;
        }

7.獲取XML指定節點的屬性：

        /// <summary>  
        /// 功能:讀取指定節點的指定屬性值     
        /// </summary>
        /// <param name="path"></param>
        /// <param name="strNode">節點名稱</param>  
        /// <param name="strAttribute">此節點的屬性</param>  
        /// <returns></returns>  
        public string GetXmlNodeAttributeValue(string path, string strNode, string strAttribute)
        {
            var strReturn = "";
            try
            {
                var xml = new XmlDocument();
                xml.Load(path);
                //根據指定路徑獲取節點  
                var xmlNode = xml.SelectSingleNode(strNode);
                if (xmlNode != null)
                {
                    //獲取節點的屬性，並迴圈取出需要的屬性值  
                    var xmlAttr = xmlNode.Attributes;
                    if (xmlAttr == null) return strReturn;
                    for (var i = 0; i < xmlAttr.Count; i++)
                    {
                        if (xmlAttr.Item(i).Name != strAttribute) continue;
                        strReturn = xmlAttr.Item(i).Value;
                        break;
                    }
                }
            }
            catch (XmlException xmle)
            {
                throw new Exception(xmle.Message);
            }
            return strReturn;
        }

8.設置XML文檔中指定節點的屬性：

 /// <summary>  
        /// 功能:設置節點的屬性值     
        /// </summary>
        /// <param name="path"></param>
        /// <param name="xmlNodePath">節點名稱</param>  
        /// <param name="xmlNodeAttribute">屬性名稱</param>  
        /// <param name="xmlNodeAttributeValue">屬性值</param>  
        public void SetXmlNodeAttributeValue(string path, string xmlNodePath, string xmlNodeAttribute, string xmlNodeAttributeValue)
        {
            try
            {
                var xml = new XmlDocument();
                xml.Load(path);
                //可以批量為符合條件的節點的屬性付值  
                var xmlNode = xml.SelectNodes(xmlNodePath);
                if (xmlNode == null) return;
                foreach (var xmlAttr in from XmlNode xn in xmlNode select xn.Attributes)
                {
                    if (xmlAttr == null) return;
                    for (var i = 0; i < xmlAttr.Count; i++)
                    {
                        if (xmlAttr.Item(i).Name != xmlNodeAttribute) continue;
                        xmlAttr.Item(i).Value = xmlNodeAttributeValue;
                        break;
                    }
                }

            }
            catch (XmlException xmle)
            {
                throw new Exception(xmle.Message);
            }
        }

9.讀取XML文檔指定節點的值：

        /// <summary>
        /// 讀取XML資源中的指定節點內容
        /// </summary>
        /// <param name="source">XML資源</param>
        /// <param name="xmlType">XML資源類型：文件，字元串</param>
        /// <param name="nodeName">節點名稱</param>
        /// <returns>節點內容</returns>
        public static object GetNodeValue(string source, XmlType xmlType, string nodeName)
        {
            var xd = new XmlDocument();
            if (xmlType == XmlType.File)
            {
                xd.Load(source);
            }
            else
            {
                xd.LoadXml(source);
            }
            var xe = xd.DocumentElement;
            XmlNode xn = null;
            if (xe != null)
            {
                 xn= xe.SelectSingleNode("//" + nodeName);
                
            }
            return xn.InnerText;
        }

10.更新XML文檔指定節點的內容：

        /// <summary>
        /// 更新XML文件中的指定節點內容
        /// </summary>
        /// <param name="filePath">文件路徑</param>
        /// <param name="nodeName">節點名稱</param>
        /// <param name="nodeValue">更新內容</param>
        /// <returns>更新是否成功</returns>
        public static bool UpdateNode(string filePath, string nodeName, string nodeValue)
        {            
            try
            {
                bool flag;
                var xd = new XmlDocument();
                xd.Load(filePath);
                var xe = xd.DocumentElement;
                if (xe == null) return false;
                var xn = xe.SelectSingleNode("//" + nodeName);
                if (xn != null)
                {
                    xn.InnerText = nodeValue;
                    flag = true;
                }
                else
                {
                    flag = false;
                }
                return flag;
            }
            catch (Exception ex)
            {
                throw new Exception(ex.Message);
            }
           
        }

11.將對象轉化為XML文件，並存入指定目錄：

        /// <summary>
        /// 將對象轉化為xml，並寫入指定路徑的xml文件中
        /// </summary>
        /// <typeparam name="T">C#對象名</typeparam>
        /// <param name="item">對象實例</param>
        /// <param name="path">路徑</param>
        /// <param name="jjdbh">標號</param>
        /// <param name="ends">結束符號（整個xml的路徑類似如下：C:\xmltest\201111send.xml，其中path=C:\xmltest,jjdbh=201111,ends=send）</param>
        /// <returns></returns>
        public static string WriteXml<T>(T item, string path, string jjdbh, string ends)
        {
            if (string.IsNullOrEmpty(ends))
            {
                //預設為發送
                ends = "send";
            }
            //控制寫入文件的次數
            var i = 0;
            //獲取當前對象的類型，也可以使用反射typeof(對象名)
            var serializer = new XmlSerializer(item.GetType());
            //xml的路徑組合
            object[] obj = { path, "\\", jjdbh, ends, ".xml" };
            var xmlPath = string.Concat(obj);
            while (true)
            {
                try
                {
                    //用filestream方式創建文件不會出現“文件正在占用中，用File.create”則不行
                    var fs = System.IO.File.Create(xmlPath);
                    fs.Close();
                    TextWriter writer = new StreamWriter(xmlPath, false, Encoding.UTF8);
                    var xml = new XmlSerializerNamespaces();
                    xml.Add(string.Empty, string.Empty);
                    serializer.Serialize(writer, item, xml);
                    writer.Flush();
                    writer.Close();
                    break;
                }
                catch (Exception)
                {
                    if (i < 5)
                    {
                        i++;
                        continue;
                    }
                    break;
                }
            }
            return SerializeToXmlStr<T>(item, true);
        }

12.向一個已經存在的父節點中插入一個子節點：

        /// <summary>  
        /// 向一個已經存在的父節點中插入一個子節點  
        /// </summary>
        /// <param name="path"></param>
        /// <param name="parentNodePath">父節點</param>
        /// <param name="childnodename">子節點名稱</param>  
        public void AddChildNode(string path, string parentNodePath, string childnodename)
        {
            try
            {
                var xml = new XmlDocument();
                xml.Load(path);
                var parentXmlNode = xml.SelectSingleNode(parentNodePath);
                XmlNode childXmlNode = xml.CreateElement(childnodename);
                if ((parentXmlNode) != null)
                {
                    //如果此節點存在    
                    parentXmlNode.AppendChild(childXmlNode);
                }
                else
                {
                    //如果不存在就放父節點添加  
                    GetXmlRoot(path).AppendChild(childXmlNode);
                }

            }
            catch (XmlException xmle)
            {
                throw new Exception(xmle.Message);
            }
        }

   以上的方法總結採用.net4.5版本和c#6.0語法