如何使用LINQ来识别特定节点是否存在？

Question

示例XML：

<MenuDataResult> 
    <Items> 
    <Item> 
     <ItemType>Submenu</ItemType> 
     <ItemTitle>Level22</ItemTitle> 
     <Menu> 
     <MenuSelected>false</MenuSelected> 
     <ChildMenuSelected>false</ChildMenuSelected> 
     </Menu> 
    </Item> 
    <Item> 
     <ItemType>Submenu</ItemType> 
     <ItemTitle>Level21</ItemTitle> 
     <Menu> 
     <MenuSelected>false</MenuSelected> 
     <!--if ChildMenuSelected = true --> 
     <ChildMenuSelected>true</ChildMenuSelected> 
     <Item> 
      <ItemType>Submenu</ItemType> 
      <ItemSubType>0</ItemSubType> 
      <Menu> 
      <!--if MenuSelected = true --> 
      <MenuSelected>true</MenuSelected> 
      <ChildMenuSelected>false</ChildMenuSelected> 
      <!-- whether this below item exists or not --> 
      <Item> 
       <ItemType>Submenu</ItemType> 
       <Menu> 
        <MenuSelected>false</MenuSelected> 
        <ChildMenuSelected>false</ChildMenuSelected> 
       </Menu> 
      </Item> 
      </Menu> 
     </Item> 
     <Item> 
      <ItemType>Submenu</ItemType> 
      <ItemTitle>Level32</ItemTitle> 
      <Menu> 
      <MenuSelected>false</MenuSelected> 
      <ChildMenuSelected>false</ChildMenuSelected> 
      </Menu> 
     </Item> 
     <Item> 
      <ItemType>Library</ItemType> 
      <ItemTitle>about_banner</ItemTitle> 
     </Item> 
     <Item> 
      <ItemType>ExternalLink</ItemType> 
      <ItemTitle>Google</ItemTitle> 
     </Item> 
     </Menu> 
    </Item> 
    </Items> 
</MenuDataResult> 

Answer 1

选择所有节点，然后比较标签名称...

var xmlString = @"<?xml version=""1.0""?><Root><NodeA></NodeA></Root>"; 

var xmlDoc = new XmlDocument(); 
xmlDoc.LoadXml(xmlString); 
var nodes = xmlDoc.SelectNodes("//*"); 

var hasNodeA = nodes.Cast<XmlNode>().Any(n => n.Name == "NodeA"); // true 
var hasNodeB = nodes.Cast<XmlNode>().Any(n => n.Name == "NodeB"); // false