使用C#

时间:2016-08-14 08:59:51

标签: c# xml

这是我给出的XML: -

<?xml version="1.0" encoding="utf-8"?>
<Processes>
  <Process Name="Process1" Namespace="" Methodname="">
    <Validations/>
    <Transformations/>
    <Routings/>
  </Process>
</Processes>

我想在 Validations 中添加新节点 Validation ,为此我编写了以下代码: -

XmlDocument originalXml = new XmlDocument();
originalXml.Load(@"C:\Users\Sid\Desktop\Process\Process1.xml");    
XmlNode Validations = originalXml.SelectSingleNode("/Processes/Process[Name="Process1"]/Validations");
XmlNode Validation = originalXml.CreateNode(XmlNodeType.Element, "Validation",null);
Validation.InnerText = "This is my new Node";
Validations.AppendChild(Validation);
originalXml.Save(@"C:\Users\Sid\Desktop\Process\Process1.xml");

但是,我在行中出现错误&#34; Validations.AppendChild(validation)&#34; as 对象引用未设置为对象的实例。请提出一些解决方法。

2 个答案:

答案 0 :(得分:3)

你可以这样做

XDocument doc = XDocument.Load(@"C:\Users\Sid\Desktop\Process\Process1.xml");
var a = doc.Descendants("Validations").FirstOrDefault();
a.Add(new XElement("Validation", "This is my new Node"));
doc.Save(@"C:\Users\Sid\Desktop\Process\Process1.xml");

答案 1 :(得分:0)

您的SelectSingleNode()没有匹配任何元素,因此是空引用异常。除了冲突的双引号问题,您应该使用@attribute_name模式使用XPath引用属性。所以正确的表达方式是:

originalXml.SelectSingleNode("/Processes/Process[@Name='Process1']/Validations");