XmlDocument xml = new XmlDocument();
xml.Load("XML路径");
Console.WriteLine(xml.DocumentElement.Name);

------解决方案--------------------
using (Stream st = File.OpenRead("xml文件路径"))
           {
               using (StreamReader sr = new StreamReader(st, Encoding.UTF8))
               {
                   XDocument xdoc = XDocument.Load(sr);
                   //获得根节点XElement
                   XElement xe = xdoc.Root;
               }
           }

XDocument是.NET 4.0

------解决方案--------------------
C# code

           path = @"./xxxxx.xml";          
           if (File.Exists(kinfopath))
           {
              XElement xmldoc = XElement.Load(path);
              string str = xmldoc.Name.ToString();
            
           }

------解决方案--------------------
C# code
 path = @"./xxxxx.xml";          
           if (File.Exists(path))
           {
              XElement xmldoc = XElement.Load(path);
              string str = xmldoc.Name.ToString();
            
           }