C# XML问题

Question

XML
------------------------------------------
<AllCategories>
  <Category>
     <CategoryID>1</CategoryID>
     <CategoryName>zhangsan</CategoryName>
     <Description>XML--C#</Description>
     <Catalogs>
        <catalog>1-page</catalog>
        <catalog>2-page</catalog>
        <catalog>3-page</catalog>
        <catalog>4-page</catalog>
     </Catalogs>
  </Category>
</AllCategories>------------------------------------------------我要查看Category中的节点个数，它有CategoryID，CategoryName，Description，Catalogs。四个。
用语句怎么查询呢？如果查Catalogs 中的catalog中的个数呢？方法是不是跟上面的思路一样？

Answer 1

            DataSet ds = new DataSet();
            ds.ReadXml("123.xml");
            Console.WriteLine(ds.Tables["Category"].Rows.Count);//1我想要的是4,上面的语句知道.
XmlNode.ChildNodes.Count 怎么用呢?.NET 3.0 我有.

Answer 2

xmlnode xln=objDoc.SelectSingleNode("AllCategories/Category/Catalogs");