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:
至此我们已经成功读取到该节点,关于XML的简单操作就介绍到这里。XML的其他操作还有XmlPath的方式,以及各种其他复杂的方式。不过对于XML本身,可以理解为一个DOM,也就是一种特殊的HTML,它拥有自己的标记格式,抛砖引玉,希望大家提出批评和建议。
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之前因为手误的原因,在本地的方法中加入了ds这个参数,后来发现文中完全没有用到这个参数,感谢@佩恩六道的指正,原文已经修改。
ADO.NET系列之操作XML(一)