第一次学习弄，也是上网看别人的思路，主要就是首先将XML读取到表里面，然后利用TreeList的两个属性：KeyFieldName和ParentFieldName两个属性的值，默认分别是ID,ParentID，二者的关系就是涉及到树形结构的层次关系。所创建的表中务必要包含二两个属性。下面上代码：

            DataTable dt = new DataTable();
      DataColumn did = new DataColumn("ID",Type.GetType("System.Int32"));
      DataColumn dParentID = new DataColumn("ParentID",Type.GetType("System.Int32"));
      DataColumn dNodeName = new DataColumn("节点名称",Type.GetType("System.String"));
      dt.Columns.Add(did);
      dt.Columns.Add(dParentID);
      dt.Columns.Add(dNodeName);

      XmlDocument xmlDoc = new XmlDocument();
      xmlDoc.Load(xmlPath);
      int Id = 1;
      int ParentId=0;
      //获取根节点
      XmlElement xmlRootElement=xmlDoc.DocumentElement;
      DataRow dr = dt.NewRow();
      dr["ID"] = Id++;
      dr["ParentID"] = 0;
      dr["节点名称"] = xmlRootElement.Name.ToString();
      dt.Rows.Add(dr);
      XmlNodeList xmlNodeList = xmlRootElement.ChildNodes;
      foreach (XmlElement xmlElement in xmlNodeList)
      {
        dr = dt.NewRow();
        dr["ID"] = Id++;
        dr["ParentID"] = ParentId;
        dr["节点名称"] = xmlElement.Name.ToString();
        dt.Rows.Add(dr);
        int parentId = Id-1;
        //遍历该节点下面的子节点
        XmlNodeList ChildNodeList = xmlElement.ChildNodes;
        foreach (XmlNode xmlNode in ChildNodeList)
        {
          dr = dt.NewRow();
          dr["ID"] = Id++;
          dr["ParentID"] = parentId;
          dr["节点名称"] = xmlNode.Name.ToString();
          dt.Rows.Add(dr);
        }    
      }
  this.treeList1.DataSource=dt;