ADO.NET系列之操作XML(一)

浏览数：25 / 时间：2015年06月09日

　　如题，我们保存数据的方式有很多种。在ASP.NET中，可以通过js赋值隐藏域的方式，也可以通过ViewState，Session这样的内置对象，还可以通过数据库的形式。现在经常用到的就是XML了，它的结构灵活，同时占用的空间很少，也比较容易操作，今天我们就来说说ADO.NET中，如何去操作XML。

　　首先我们可以在一个页面上，放入一个GridView用来显示读取的XML的数据(这里使用的是经典的books.xml，在一些网站上可以下载)，同时再放入一个富文本框来显示特定的节点，还有一个按钮用于点击后在文本框中显示XML特定节点的内容：

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="XmlToDataTable.aspx.cs"
    Inherits="WebApplication1.XmlToDataTable" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:TextBox ID="txtShow" runat="server" TextMode="MultiLine" Width="100%"></asp:TextBox>
        <asp:GridView ID="gvXML" runat="server" AutoGenerateColumns="false">
            <Columns>
                <asp:BoundField HeaderText="Id" DataField="id" />
                <asp:BoundField HeaderText="Author" DataField="author" />
                <asp:BoundField HeaderText="Title" DataField="title" />
                <asp:BoundField HeaderText="Genre" DataField="genre" />
                <asp:BoundField HeaderText="Price" DataField="price" />
                <asp:BoundField HeaderText="Publish_date" DataField="publish_date" />
                <asp:BoundField HeaderText="Description" DataField="description" />
            </Columns>
        </asp:GridView>
        <asp:Button ID="btnExport" runat="server" Text="导出XML" OnClick="btnExport_Click" />
    </div>
    </form>
</body>
</html>

　　大家可以看到我在GridView中绑定了一些列，而这些列正是我们的XML拥有的一些节点：

<?xml version="1.0"?>
-<catalog> -<book id="bk101"> <author>Gambardella, Matthew</author> <title>XML Developer‘s Guide</title> <genre>Computer</genre> <price>44.95</price> <publish_date>2000-10-01</publish_date> <description>An in-depth look at creating applications with XML.</description> </book> +<book id="bk102"> -<book id="bk103"> <author>Corets, Eva</author> <title>Maeve Ascendant</title> <genre>Fantasy</genre> <price>5.95</price> <publish_date>2000-11-17</publish_date> <description>After the collapse of a nanotechnology society in England, the young survivors lay the foundation for a new society.</description> </book> -<book id="bk104"> <author>Corets, Eva</author> <title>Oberon‘s Legacy</title> <genre>Fantasy</genre> <price>5.95</price> <publish_date>2001-03-10</publish_date> <description>In post-apocalypse England, the mysterious agent known only as Oberon helps to create a new life for the inhabitants of London. Sequel to Maeve Ascendant.</description> </book> -<book id="bk105"> <author>Corets, Eva</author> <title>The Sundered Grail</title> <genre>Fantasy</genre> <price>5.95</price> <publish_date>2001-09-10</publish_date> <description>The two daughters of Maeve, half-sisters, battle one another for control of England. Sequel to Oberon‘s Legacy.</description> </book> -<book id="bk106"> <author>Randall, Cynthia</author> <title>Lover Birds</title> <genre>Romance</genre> <price>4.95</price> <publish_date>2000-09-02</publish_date> <description>When Carla meets Paul at an ornithology conference, tempers fly as feathers get ruffled.</description> </book> -<book id="bk107"> <author>Thurman, Paula</author> <title>Splish Splash</title> <genre>Romance</genre> <price>4.95</price> <publish_date>2000-11-02</publish_date> <description>A deep sea diver finds true love twenty thousand leagues beneath the sea.</description> </book> -<book id="bk108"> <author>Knorr, Stefan</author> <title>Creepy Crawlies</title> <genre>Horror</genre> <price>4.95</price> <publish_date>2000-12-06</publish_date> <description>An anthology of horror stories about roaches, centipedes, scorpions and other insects.</description> </book> -<book id="bk109"> <author>Kress, Peter</author> <title>Paradox Lost</title> <genre>Science Fiction</genre> <price>6.95</price> <publish_date>2000-11-02</publish_date> <description>After an inadvertant trip through a Heisenberg Uncertainty Device, James Salway discovers the problems of being quantum.</description> </book> -<book id="bk110"> <author>O‘Brien, Tim</author> <title>Microsoft .NET: The Programming Bible</title> <genre>Computer</genre> <price>36.95</price> <publish_date>2000-12-09</publish_date> <description>Microsoft‘s .NET initiative is explored in detail in this deep programmer‘s reference.</description> </book> -<book id="bk111"> <author>O‘Brien, Tim</author> <title>MSXML3: A Comprehensive Guide</title> <genre>Computer</genre> <price>36.95</price> <publish_date>2000-12-01</publish_date> <description>The Microsoft MSXML3 parser is covered in detail, with attention to XML DOM interfaces, XSLT processing, SAX and more.</description> </book> -<book id="bk112"> <author>Galos, Mike</author> <title>Visual Studio 7: A Comprehensive Guide</title> <genre>Computer</genre> <price>49.95</price> <publish_date>2001-04-16</publish_date> <description>Microsoft Visual Studio 7 is explored in depth, looking at how Visual Basic, Visual C++, C#, and ASP+ are integrated into a comprehensive development environment.</description> </book> </catalog>

　　嗯，貌似看起来有些乱，不过马上我们处理了之后，它就会变得整齐。接下来在后台我们开始操作XML，首先我们需要让GridView显示数据：首先我们需要建立一个数据集DataSet，然后使用ADO.NET中自带的方法去读取XML，这里的实现很简单：

 DataSet ds = new DataSet(); 
 string Path = Server.MapPath("XML/books.xml");
 ds.ReadXml(Path);

　　这样我们的ds中就已经有数据了，接下来绑定GridView后，呈现出来的就是这样：

　　这时候我们的XML已经读取成功了，接下来我们可以简单的操作下XML中的节点：

       private void ShowXML(string Path) 
        {  
            XmlDocument doc = new XmlDocument();
            doc.Load(Path);
            XmlNodeList nodeList = doc.SelectNodes("//title");
            foreach(XmlNode node in nodeList)            
            {
                txtShow.Text += node.InnerXml + "\r\n";
            }
        }

        protected void btnExport_Click(object sender, EventArgs e)
        {
            string Path = Server.MapPath("XML/books.xml");
            ShowXML(Path);
        }

　　　这里我们用到了XmlDocument类，这个类是用于表示整个XML的DOM，另外一个XmlNode类是表示XML中的一个节点，而XmlNodeList则是表示可以迭代的，XmlNode的一个集合，我们在这里是在加载了DOM对象后，选择了title节点的集合，然后遍历出每个节点下的内容并赋值给txtShow，效果如下：