一个用于读写XML文档的类

//writer:furenjun 2006.05.05
using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;

using System.Xml;
using System.Xml.Xsl;
using System.Xml.XPath;
using System.Text;
namespace MrfuReadAndWriteXmlFile
{
    /**//// <summary>
    /// C_MrFuXmlManager 的摘要说明。
    /// </summary>
    public class C_MrFuXmlManager
    {
        public C_MrFuXmlManager()
        {
            //
            // TODO: 在此处添加构造函数逻辑
            //
        }

        string myXmlFilePath=Application.StartupPath +@"\Users.xml";
        string tempFilePath=Application.StartupPath +@"\Temp.xml";
        public string GsXmlFilePath
        {
            get{return myXmlFilePath;}
            set{myXmlFilePath=value;}
        }

        XmlDocument Operation#region XmlDocument Operation
    
        /**//// <summary>
        /// 创建xml文档
        /// </summary>
        /// <returns></returns>
        public  bool CreateMyXmlFile()
        {
            
            try
            {
                XmlTextWriter myTextWriter=new XmlTextWriter (this.GsXmlFilePath ,System.Text.Encoding.GetEncoding("GB2312")    );

                myTextWriter.Formatting =Formatting.Indented;  //写入文本的缩进格式
                myTextWriter.WriteStartDocument(true);  //设置standalone="no"   //当为（true）时 <?xml version="1.0" standalone="yes" ?> 
                //如果 XML 文档所需要的所有实体声明都包含在文档内，则有效值为 yes，或者如果需要外部 DTD，则为 no。如果 XML 声明中没有独立特性，该属性将返回 String.Empty。
                myTextWriter.WriteDocType("mrfuDocType",null,null,null) ; 
                myTextWriter.WriteComment("System user info,warning : do not modify! "); //添加注释
                //myTextWriter.WriteStartElement("mrfu");
                //Write the namespace declaration.
                //myTextWriter.WriteAttributeString("xmlns", "Users", null, "urn:UsersInfo");//为前面的element写属性

                myTextWriter.WriteStartElement("mrfu","Users","urn:UsersInfo");
                //            myTextWriter.WriteElementString("Name","Fu") ;
                //            myTextWriter.WriteElementString("Pwd","renjun") ;
                //            myTextWriter.WriteElementString("DateOfLastlogin","06/08/1982") ;
                myTextWriter.WriteEndElement() ;
                //            myTextWriter.WriteEndElement() ; //与上呼应,对应一个单元 区间.
            
                //write the xml to file and close the myTextWriter
                myTextWriter.Flush();
                myTextWriter.Close(); 
                //MessageBox.Show ("写入数据完毕.");
                
            }
            catch
            {
                return false;
            }
            return true;
        }

        /**//// <summary>
        /// 返回指定xml文档的数据集
        /// </summary>
        /// <returns></returns>
        public DataSet GetMyXmlData()
        {
            DataSet myDataSet=null;
            
            try
            {
                myDataSet= new DataSet();

                myDataSet.ReadXml(this.GsXmlFilePath ); 
                //MessageBox.Show (myDataSet.Tables[0].TableName.ToString () );
            }

            catch (Exception e1)
            {
                MessageBox.Show (e1.Message.ToString()  ) ;
        
            }
            return  myDataSet;
        }


        /**//// <summary>
        /// 插入数据至xml文档
        /// </summary>
        /// <param name="usInfo"></param>
        /// <returns></returns>
        public bool InsertDataInXmlFile(UserInfo usInfo)
        {
            
            try
            {
                XmlTextWriter TWriter=new XmlTextWriter(this.tempFilePath ,Encoding.GetEncoding("GB2312") );
                TWriter.WriteStartDocument();
                TWriter.WriteStartElement("mrfu","Users","urn:UsersInfo");
                TWriter.WriteStartElement("User");
                TWriter.WriteAttributeString("Id",usInfo.Id); //对前面的User写出具有指定的本地名称和值的属性
                TWriter.WriteElementString("Name",usInfo.Name );
                TWriter.WriteElementString("Pwd",usInfo.Pwd );
                TWriter.WriteElementString("AreaFlag",usInfo.AreaFlag );
                TWriter.WriteElementString("DateOfLastlogin",System.DateTime.Now.ToString()   );
            
                TWriter.WriteEndElement();
                TWriter.WriteEndElement();
                TWriter.WriteEndDocument();

                TWriter.Flush();
                TWriter.Close();
                SaveUserInfo(this.tempFilePath );
            }
            catch
            {
                return false;
            }
            return true;
            
        }

        /**//// <summary>
        /// 保存数据至xml文档,与前面的插入方法结合使用.
        /// </summary>
        /// <param name="path"></param>
        private void SaveUserInfo(string path)
        {    
            

            XmlDocument xdoc=new XmlDocument();
            xdoc.Load(this.GsXmlFilePath );

            XmlDocument xdocImp=new XmlDocument();
            xdocImp.Load(path);

            XmlNodeList pNodes=xdocImp.SelectNodes("//User");

            NameTable nametable=new NameTable();
            XmlNamespaceManager nameMan=new XmlNamespaceManager(nametable);
            nameMan.AddNamespace("mrfu","urn:UsersInfo");

            foreach(XmlNode pNode in pNodes)
            {
                XmlNode pNodeImp=xdoc.SelectSingleNode("//User[Name='"+pNode.ChildNodes.Item(0).InnerXml+"']");
                if(pNodeImp==null)  
                {
                    XmlNode importedNode=xdoc.ImportNode(pNode,true);
                    xdoc.SelectSingleNode("//mrfu:Users",nameMan).AppendChild(importedNode);
                }
            }
            xdoc.Save(this.GsXmlFilePath );
            
            
        }
        #endregion

        /**//// <summary>
        /// 按用户名查找用户的相关信息
        /// </summary>
        /// <param name="UserName"></param>
        /// <returns></returns>
        public UserInfo GetUserInfo(string UserName)
        {

            UserInfo usInfo=new UserInfo();
            
            if(this.GetNumOfChild(UserName)<0 )
                return usInfo;

            XmlDocument xdoc=new XmlDocument();
            xdoc.Load(this.GsXmlFilePath );
            XmlNodeList xList=xdoc.SelectNodes("//User[Name='"+UserName+"']");
            foreach(XmlNode node in xList)
            {
                XmlNodeReader NReader=new XmlNodeReader(node);
                try
                {
                    while(NReader.Read())
                    {
                        if(NReader.NodeType==XmlNodeType.Element)
                        {
                            if(NReader.HasAttributes)
                            {
                                while(NReader.MoveToNextAttribute())
                                {
                                    if(NReader.Value!="urn:UsersInfo")
                                    {
                                        usInfo.Id=NReader.Value;
                                    }
                                }
                            }
                        }
                        if(NReader.Name=="Name")
                        {
                            usInfo.Name =NReader.ReadString();
                        }
                        else if(NReader.Name=="Pwd")
                        {
                            usInfo.Pwd =NReader.ReadString();
                        }
                        else if(NReader.Name=="AreaFlag")
                        {
                            usInfo.AreaFlag =NReader.ReadString();
                        }
                        else if(NReader.Name=="DateOfLastlogin")
                        {
                            usInfo.DateOfLastlogin =NReader.ReadString();
                        }

                    }
                }
                catch(Exception err)
                {
                    string errmsg="read xml file error \n"+err.ToString();
                    MessageBox.Show(errmsg);
                }
                finally
                {
                    if(NReader!=null)
                    {

                        NReader.Close();
                    }

                    
                }
                
            }
        
            return usInfo;
        }

        /**//// <summary>
        /// 查找用户信息返回用户id的数据表
        /// </summary>
        /// <param name="UserName"></param>
        /// <returns></returns>
        public  DataTable GetUserID(string UserName)
        {
            
            DataTable dt=new DataTable();
            
            if(this.GetNumOfChild(UserName)<0 )
                return dt;
            XmlDocument xdoc=new XmlDocument();
            xdoc.Load(this.GsXmlFilePath );
            
            XmlNodeList xList=xdoc.SelectNodes("//User[Name='"+UserName+"']");//可以根据实际需要更改它的查找范围.如SelectNodes("//User")
        

            if (xList.Count> 0)
            {
                CreateColumns(dt, xList[0]);
            }
            foreach(XmlNode node in xList)
            {
                DataRow dr=dt.NewRow();
                foreach(XmlAttribute attr in node.Attributes)
                {
                    dr[attr.Name]=attr.Value;
                }
                dt.Rows.Add(dr);
            }
            return dt;
        }

        /**//// <summary>
        /// 创建列
        /// </summary>
        /// <param name="dt"></param>
        /// <param name="node"></param>
        protected static void CreateColumns(DataTable dt, XmlNode node)
        {
            foreach(XmlAttribute attr in node.Attributes)
            {
                dt.Columns.Add(new DataColumn(attr.Name));
            }
        }
        


        /**//// <summary>
        /// 查找当前用户结点的位置
        /// </summary>
        /// <param name="UserName"></param>
        /// <returns></returns>
        public int GetNumOfChild(string UserName)
        {
            if(!VerifyParameters())
                return -1;
            int i=-1;
            ArrayList myArylist=new ArrayList(); 
            XmlDocument xdoc=new XmlDocument();
            xdoc.Load(this.GsXmlFilePath  );
            XmlNodeList xList=xdoc.SelectNodes("//User");

            int j=0;
            int totalNum=xList.Count ;
            bool find=false;
            while((j<totalNum)&&(!find))
            {
                if(xList[j].ChildNodes.Item(0).InnerText.Trim()==UserName.Trim() )
                {
                    i=j;
                    find=true;
                }
                j++;
                
            }
            return i;
        }

        /**//// <summary>
        /// 获取所有的用户名称 
        /// </summary>
        /// <returns></returns>
        public ArrayList GetTheNameOfAllUser( )
        {
            ArrayList myArylist=new ArrayList(); 
            XmlDocument xdoc=new XmlDocument();
            xdoc.Load(this.GsXmlFilePath  );
            XmlNodeList xList=xdoc.SelectNodes("//User");
            foreach(XmlNode xNode in xList)
            {
                myArylist.Add(xNode.ChildNodes.Item(0).InnerText); //也可显示文档中的其它项,更改item(i)即可
            }
            return myArylist;
        }

        /**//// <summary>
        /// 更新指定用户的信息
        /// </summary>
        /// <param name="UserName"></param>
        /// <param name="usInfo"></param>
        /// <returns></returns>
        public bool UpdateNotes(string UserName,UserInfo usInfo)
        {
            if(this.GetNumOfChild(UserName)<0 )
                return false;
            try
            {
                XmlDocument xdoc=new XmlDocument();
                xdoc.Load(this.GsXmlFilePath  );
            
                //创建一个文档片断来存储要替换的节点
                XmlDocumentFragment xdocFrag=xdoc.CreateDocumentFragment();
                //新节点的根节点
                XmlElement newElement=xdoc.CreateElement("User");
                XmlAttribute newID=xdoc.CreateAttribute("Id");

                newID.Value=usInfo.Id ;
                newElement.Attributes.SetNamedItem(newID);

                XmlElement newName=xdoc.CreateElement("Name");
                newName.InnerText=UserName;
                newElement.AppendChild(newName);

                XmlElement newPwd=xdoc.CreateElement("Pwd");

                newPwd.InnerText=usInfo.Pwd ;
                newElement.AppendChild(newPwd);

                XmlElement newAreaFlag=xdoc.CreateElement("AreaFlag");
                newAreaFlag.InnerText=usInfo.AreaFlag ;
                newElement.AppendChild(newAreaFlag);

                XmlElement newDateOfLastlogin=xdoc.CreateElement("DateOfLastlogin");
                newDateOfLastlogin.InnerText=System.DateTime.Now.ToString()  ;
                newElement.AppendChild(newDateOfLastlogin);

            
            
                //把新创建的节点加入文档片断
                xdocFrag.AppendChild(newElement);
            
                //确定要替换的节点作替换
                NameTable nametable=new NameTable();
                XmlNamespaceManager nameMan=new XmlNamespaceManager(nametable);
                nameMan.AddNamespace("mrfu","urn:UsersInfo");

                XmlElement xUsers=(XmlElement)xdoc.SelectSingleNode("//mrfu:Users",nameMan);
                //找到该用户在文档中的结点序号(第几个孩子)
                int i=GetNumOfChild(UserName);
                if(i>=0)
                {
                    XmlElement xChild=(XmlElement)xUsers.ChildNodes[i];
                    xUsers.ReplaceChild(xdocFrag.FirstChild,xChild);

                    xdoc.Save(this.GsXmlFilePath );
                    
                }
                else
                    return false;

            }
            catch
            {
                return false;
            }
            return true;
        
        
        }

        /**//// <summary>
        /// 删除指定用户的纪录
        /// </summary>
        /// <param name="UserName"></param>
        /// <returns></returns>
        public bool DeleteNotes(string UserName)
        {
            try
            {
                XmlDocument xdoc=new XmlDocument();
                xdoc.Load(this.GsXmlFilePath  );

                NameTable nametable=new NameTable();
                XmlNamespaceManager nameMan=new XmlNamespaceManager(nametable);
                nameMan.AddNamespace("mrfu","urn:UsersInfo");

                XmlNode rootnode=xdoc.SelectSingleNode("//mrfu:Users",nameMan);
                XmlNode node=xdoc.SelectSingleNode("//User[Name='"+UserName+"']");
                rootnode.RemoveChild(node);
                xdoc.Save(this.GsXmlFilePath );
            }
            catch
            {
                return false;

            }
            return true;
            
        }





        /**//// <summary>
        /// 验证xml文档的有效性
        /// </summary>
        /// <returns></returns>
        protected  bool VerifyParameters()
        {
            bool bls=true;
            if (!System.IO.File.Exists (this.GsXmlFilePath ))
            {
            
                bls=false;
                throw(new Exception("xmlFile do not exists."));
                
            }
            else
            {
                XmlDocument doc=new XmlDocument();
                doc.Load(this.GsXmlFilePath  );

                if (doc == null)
                {
                    bls=false;
                    throw new Exception("doc cannot be null.");
                
                }
                if (doc.LastChild.GetType() == typeof(System.Xml.XmlDeclaration))
                {
                    bls=false;
                    throw new Exception("XmlDocument requires at least the a root node");
                
                }
            }
            return bls;
        }



    

        /**//// <summary>
        /// 获取当前根结点下的所有纪录值
        /// </summary>
        /// <returns></returns>
        public  DataTable GetDataFromXmlFile( )
        {
            
            VerifyParameters();

            XmlDocument doc=new XmlDocument();
            doc.Load(this.GsXmlFilePath  );

            DataTable myTable=new DataTable();
            
            XmlNodeList xList=doc.SelectNodes("//User");

            
            // create data table
            DataTable dt = new DataTable(); 

            //读取它的元素名称
            
            dt.Columns.Add(new DataColumn("Id"));
            dt.Columns.Add(new DataColumn("Pwd"));
            dt.Columns.Add(new DataColumn("AreaFlag"));
            dt.Columns.Add(new DataColumn("DateOfLastlogin"));

            //将各个元素对应的值一行一行写入表中
            DataRow row = null; 
            
            foreach(XmlNode xNode in xList)
            {
                row = dt.NewRow(); 
                for(int j=0;j<4;j++)
                {
                    row[j]=xNode.ChildNodes.Item(j).InnerText; 
                }
                dt.Rows.Add( row ); 
                
            }
        
            dt.AcceptChanges(); 
            return dt; 
            
        }

        
        
        

    }



    public class UserInfo
    {
        public string   Id="";
        public String   Name="";
        public string   Pwd="";
        public string   AreaFlag="";
        public string   DateOfLastlogin="";
//        public String   Symbol="";
//        public double   Last;
//        public DateTime Date;
//        public double   Change;
//        public double   Open;
//        public double   High;
//        public double   Low;
//        public long     Volume;
//        public long     MarketCap;
//        public double   PreviousClose;
//        public double   PreviousChange;
//        public double   Low52Week;
//        public double   High52Week;
        
    }

}