Question

我正在尝试使用Linq过滤xmldata到Xml，问题是我无法使用XElement.Elements（Xname）方法获取元素但是在使用XElement.Desendents（Xname）方法时它工作正常但显示所有我不想要的元素。我想要它应该显示所有元素和属性，其元素和属性名称在两个文本框中传递。

XML：

<?xml version="1.0" ?> 
<Summary AvailableRules="71000" SelectedRules="445" OmittedRules="6887">
  <BBCE AvailableRules="69" SelectedRules="4" OmittedRules="65">
    <SelectedRules>
      <Rule RuleID="jc_0201" Priority="Strongly Recommended" /> 
      <Rule RuleID="jc_0211" Priority="Strongly Recommended" /> 
      <Rule RuleID="jc_0221" Priority="Strongly Recommended" /> 
      <Rule RuleID="jc_0231" Priority="Strongly Recommended" /> 
    </SelectedRules>
    <OmittedRules>
      <Rule RuleID="ar_0001" Priority="Mandatory" /> 
      <Rule RuleID="ar_0002" Priority="Mandatory" /> 
      <Rule RuleID="db_0143_a" Priority="Strongly Recommended" /> 
      <Rule RuleID="db_0143_b" Priority="Strongly Recommended" /> 
      <Rule RuleID="jc_0311" Priority="Mandatory" /> 
      <Rule RuleID="jc_0321" Priority="Mandatory" /> 
      <Rule RuleID="jc_0331" Priority="Mandatory" /> 
      <Rule RuleID="jc_0341" Priority="Mandatory" /> 
      <Rule RuleID="jc_0011" Priority="Strongly Recommended" /> 
      <Rule RuleID="jc_0021" Priority="Strongly Recommended" /> 
      <Rule RuleID="na_0004_a" Priority="Recommended" /> 
      <Rule RuleID="na_0004_b" Priority="Recommended" /> 
      <Rule RuleID="db_0043" Priority="Strongly Recommended" /> 
      <Rule RuleID="db_0042" Priority="Strongly Recommended" /> 
      <Rule RuleID="na_0005" Priority="Strongly Recommended" /> 
      <Rule RuleID="jc_0081" Priority="Recommended" /> 
      <Rule RuleID="jm_0002" Priority="Mandatory" /> 
      <Rule RuleID="db_0142" Priority="Strongly Recommended" /> 
      <Rule RuleID="jc_0061" Priority="Recommended" /> 
      <Rule RuleID="db_0146" Priority="Strongly Recommended" /> 
      <Rule RuleID="db_0140" Priority="Recommended" /> 
      <Rule RuleID="jm_0013" Priority="Strongly Recommended" /> 
      <Rule RuleID="db_0032" Priority="Strongly Recommended" /> 
      <Rule RuleID="db_0141" Priority="Strongly Recommended" /> 
      <Rule RuleID="jc_0171" Priority="Strongly Recommended" /> 
      <Rule RuleID="jm_0010" Priority="Strongly Recommended" /> 
      <Rule RuleID="jc_0281" Priority="Strongly Recommended" /> 
      <Rule RuleID="na_0008" Priority="Recommended" /> 
      <Rule RuleID="na_0009" Priority="Strongly Recommended" /> 
    </OmittedRules>
  </BBCE>
</Summary>

C＃代码：

var button = sender as Button;
var parent = button.Parent as FrameworkElement;

//(Textbox to take element`s name)
var textBox = parent.FindName("textbox1") as TextBox;

var textbl = parent.FindName("abc") as TextBlock;
var com = parent.FindName("cbox1") as ComboBox;

//(Textbox to take ATTRIBUTE`s name)  
var textBox1 = parent.FindName("textbox2") as TextBox;

XElement ele = XElement.Load(txtFileName.Text);

//working with Xelement.desendents it works fine
var fil = from item in ele.Elements(textbl.Text)
          select item.Element(textBox.Text).Attribute(textBox1.Text);

foreach (var f in fil)
{
    Label lb = new Label();
    lb.Content = f;
    canvas1.Children.Add(lb);
}

我观察到的是，当只使用BBCE元素时，它工作正常，但是在添加带有属性的Summary元素（Elements方法）时，它不起作用。

我错过了什么吗？

Answer 1

Elements(name)方法返回节点的子元素。 Descendants(name)方法返回节点的后代元素。这是预期的行为。

因此，当您致电ele.Elements(textbl.Text)时，搜索只会在ele元素的直接子项之间进行。当您通过XElement ele = XElement.Load加载文件时，ele元素将成为xml的根元素。即您的案例中的<Summary>元素。它有单个孩子<BBCE>。这就是您在使用<BBCE>方法进行搜索时只能找到Elements()的原因。

在您的情况下，

Descendants()方法将搜索文档中的任何元素，但<Summary>节点本身除外。

XElement.Elements（XName）方法无法读取具有属性的xml节点

1 个答案: