XML 文档对象模型---- 将XML与XmlDocument (w3c DOM) 一起保存

如何使用 XmlDocument (W3C DOM) 保存 XML

此示例阐释如何使用 XmlDocument 类更新和保存 XML，该类是 WWW 联合会 (W3C) 文档对象模型 (DOM) 的实现。

此示例是如何加载和使用 XmlDocument 主题的继续。

VB SaveXmlDocument.aspx [ 运行示例] | [ 查看源代码]

XmlDocument 类的 Save 方法使 XmlDocument 能够将 XML 数据保存到文件、流和 XmlWriter。

该示例应用程序（如下面的代码所示）在文件 books.xml 中浏览，以将所有书籍的价格增加 2%。然后，该应用程序将 XML 保存到一个名为 updatebooks.xml 的新文件。

public void Run(String[] args) { try { // Create XmlDocument and load the XML from file XmlDocument myXmlDocument = new XmlDocument(); myXmlDocument.Load (new XmlTextReader (args[0])); Console.WriteLine ("XmlDocument loaded with XML data successfully ..."); Console.WriteLine(); IncreasePrice(myXmlDocument.DocumentElement); // Write out data as XML myXmlDocument.Save(args[1]); Console.WriteLine(); Console.WriteLine("Updated prices saved in file {0}", args[1]); } catch (Exception e) { Console.WriteLine ("Exception: {0}", e.ToString()); } } public sub Run(args As String()) try ' Create an XmlDocument Dim myXmlDocument as XmlDocument = new XmlDocument() myXmlDocument.Load (args(0)) Console.WriteLine ("XmlDocument loaded with XML data successfully ...") Console.WriteLine() IncreasePrice(myXmlDocument.DocumentElement) ' Write out data as XML myXmlDocument.Save(args(1)) Console.WriteLine() Console.WriteLine("Updated prices saved in file {0}", args(1)) catch e as Exception Console.WriteLine ("Exception: {0}", e.ToString()) end try end sub
C#	VB

IncreasePrice 方法使用 XmlNode 类的 FirstChild 方法递归地重复 XML 文档，以沿着树向下移。如果没有子节点，则此方法返回一个空值。NextSibling 属性移到紧靠在当前节点旁的节点，如果没有节点可移动，则返回一个空值。每当应用程序找到一个名为价格的节点时，它就更新该价格。下列代码显示 IncreasePrice 方法的操作原理。

public void IncreasePrice(XmlNode node) { if (node.Name == "price") { node = node.FirstChild; Decimal price = Decimal.Parse(node.Value); // Increase all the book prices by 2% String newprice = ((Decimal)price*(new Decimal(1.02))).ToString("#.00"); Console.WriteLine("Old Price = " + node.Value + "\tNew price = " + newprice); node.Value = newprice; } node = node.FirstChild; while (node != null) { IncreasePrice(node); node = node.NextSibling; } } public sub IncreasePrice(node as XmlNode) if (node.Name = "price") node = node.FirstChild Dim price as Decimal price = System.Decimal.Parse(node.Value) ' Increase all the book prices by 2% Dim newprice as String newprice = CType(price*(new Decimal(1.02)), Decimal).ToString("#.00") Console.WriteLine("Old Price = " & node.Value & Strings.chr(9) & "New price = " & newprice) node.Value = newprice end if node = node.FirstChild While Not node Is Nothing IncreasePrice(node) node = node.NextSibling end while end sub
C#	VB

XmlDocument loaded with XML data successfully ...

Old Price = 8.99        New price = 9.17

Old Price = 11.99       New price = 12.23

Old Price = 9.99        New price = 10.19

Updated prices saved in file updatebooks.xml

摘要

1. XmlDocument 类可将 XML 保存到文件、流或 XmlWriter。
2. XmlNode 类使您可以在 XML 文档中浏览并修改其中的节点。