xml的简单操作

 1.写xml

using System.Xml;

 

public void wrietXml(DataSet ds, string path)
    ...{
        XmlDocument xmlDoc;
        XmlNode xmlNode;
        XmlElement xmlElem;

        //XmlElement是XmlNode，但XmlNode不能增加属性，所以一般有了XmlElement再有XmlNode

        xmlDoc = new XmlDocument();
        //声明
        xmlNode = xmlDoc.CreateNode(XmlNodeType.XmlDeclaration, "", "");
        xmlDoc.AppendChild(xmlNode);
        //根元素
        xmlElem = xmlDoc.CreateElement("", "TableInfo", "");
        xmlDoc.AppendChild(xmlElem);
        XmlNode root = xmlDoc.SelectSingleNode("TableInfo");
        //root.AppendChild(xmlElem);

        //结构：TableInfo/table/field
        for (int i = 0; i < ds.Tables[0].Rows.Count; i++)
        ...{
            XmlElement xe1 = xmlDoc.CreateElement("field");
            string tableName = ds.Tables[0].Rows[i]["表名"].ToString();
            if (tableName != "")
            ...{//增加table节点
                xmlElem = xmlDoc.CreateElement("table");
                xmlElem.SetAttribute("name", tableName);
                xmlElem.SetAttribute("descript", "");
                root.AppendChild(xmlElem);
            }

            //增加field节点
            string fieldName = ds.Tables[0].Rows[i]["字段名"].ToString();
            xe1.SetAttribute("name", fieldName);
            xe1.SetAttribute("descript", "");
            xmlElem.AppendChild(xe1);
            
        }

        xmlDoc.Save(path);
    }

2.读xml

(1)利用dataset

protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
    ...{
        //从xml文件中读出信息
        string file = Server.MapPath("Images") + "/info.xml";
        DataSet ds = new DataSet();

        //xml文件读到dataset中
        ds.ReadXml(file);
        DataView dv = new DataView(ds.Tables[1]);
        //对dataview进行简单的查询
        dv.RowFilter = "table_Id = " + DropDownList1.SelectedItem.Value;
        DropDownList2.DataSource = dv;
        DropDownList2.DataTextField = "name";
        DropDownList2.DataValueField = "name";
        DropDownList2.DataBind();
        DropDownList2.Items.Insert(0, new ListItem("--请选择字段--","-1"));
    }

(2)使用xml命名空间

using System.Xml;

private void button1_Click(object sender, EventArgs e)
...{
            XmlDocument doc = new XmlDocument();
            doc.Load("../../XML/Expenses1.xml");
            //XmlNodeList elemList = doc.GetElementsByTagName("fourth");
            XmlNode foundnode = doc.SelectSingleNode("root");

            //所有节点放在sList
            Stack sList = new Stack(); //Stack变量本来就是指针
            int xLevel = 0;
            AllNodes(foundnode, 0, 1, ref xLevel, sList);  
}

private int AllNodes(XmlNode root, int i, int j, ref int xLevel, Stack sList)
...{//将所有节点放到队列中，并记录其信息
            //root:树根　i:以root为根的树拥有的叶子节点数,叶子节点为0  j:表示处于树的第几层　xLevel:树的高度　sList:用来存放树中所有节点的堆栈

            if (!root.HasChildNodes)
            ...{//叶节点
                node n1;
                n1.n = root;
                n1.i = i;
                n1.j = j;
                sList.Push(n1);//qList.Enqueue(n1);
                if (j > xLevel) xLevel = j;
                return 1;
            }
            else
            ...{//非叶节点
                XmlNode x = root.LastChild;//XmlNode x = root.FirstChild;
                while (x != null)
                ...{
                    i += AllNodes(x, 0, j+1, ref xLevel, sList);
                    x = x.PreviousSibling;//x = x.NextSibling;
                }

                node n2;
                n2.n = root;
                n2.i = i;
                n2.j = j;
                sList.Push(n2);//qList.Enqueue(n2);
                return i;

            }
}