如何從xml文件中過濾數據以僅顯示在樹視圖中選中的節點

Question

我在鏈接「http://msdn.microsoft.com/en-us/library/」中提供了一個名爲「books.xml」的xml文件窗戶/桌面/ ms762271（v = vs.85）的.aspx」。我的要求是僅將xml信息中的<title>作爲樹視圖中的節點來消除。但是，當我做了下面的代碼，它顯示所有的價值作爲節點像「目錄」作爲根節點，作爲父節點作爲節點，然後作者，標題，流派等節點，但我只需要根節點目錄和標題作爲節點，甚至不是書。任何機構可以引導我，我需要什麼樣的修改在exisitng邏輯用於顯示標題來做爲節點

OpenFileDialog dlg = new OpenFileDialog(); 
     dlg.Title = "Open XML document"; 
     dlg.Filter = "XML Files (*.xml)|*.xml"; 
     dlg.FileName = Application.StartupPath + "\\..\\..\\Sample.xml"; 
     if (dlg.ShowDialog() == DialogResult.OK) 
     { 
      try 
      { 
       //Just a good practice -- change the cursor to a 
       //wait cursor while the nodes populate 
       this.Cursor = Cursors.WaitCursor; 
       //First, we'll load the Xml document 
       XmlDocument xDoc = new XmlDocument(); 
       xDoc.Load(dlg.FileName); 
       //Now, clear out the treeview, 
       //and add the first (root) node 
       treeView1.Nodes.Clear(); 
       treeView1.Nodes.Add(new 
        TreeNode(xDoc.DocumentElement.Name)); 
       TreeNode tNode = new TreeNode(); 
       tNode = (TreeNode)treeView1.Nodes[0]; 
       //We make a call to addTreeNode, 
       //where we'll add all of our nodes 
       addTreeNode(xDoc.DocumentElement, tNode); 
       //Expand the treeview to show all nodes 
       treeView1.ExpandAll(); 
      } 
      catch (XmlException xExc) 
      //Exception is thrown is there is an error in the Xml 
      { 
       MessageBox.Show(xExc.Message); 
      } 
      catch (Exception ex) //General exception 
      { 
       MessageBox.Show(ex.Message); 
      } 
      finally 
      { 
       this.Cursor = Cursors.Default; //Change the cursor back 
      } 
     }} 
     //This function is called recursively until all nodes are loaded 
    private void addTreeNode(XmlNode xmlNode, TreeNode treeNode) 
    { 
     XmlNode xNode; 
     TreeNode tNode; 
     XmlNodeList xNodeList; 
     if (xmlNode.HasChildNodes) //The current node has children 
     { 
      xNodeList = xmlNode.ChildNodes; 
      for (int x = 0; x <= xNodeList.Count - 1; x++) 
      //Loop through the child nodes 
      { 
       xNode = xmlNode.ChildNodes[x]; 
       treeNode.Nodes.Add(new TreeNode(xNode.Name)); 
       tNode = treeNode.Nodes[x]; 
       addTreeNode(xNode, tNode); 
      } 
     } 
     else //No children, so add the outer xml (trimming off whitespace) 
      treeNode.Text = xmlNode.OuterXml.Trim(); 
    } 

Answer 1

我假設你的意圖是隻顯示標題和類別下的節點而已。在這種情況下，嘗試以下方法addTreeNode版本：

private void addTreeNode(XmlNode xmlNode, TreeNode treeNode) 
    { 
     XmlNode xNode; 
     TreeNode tNode; 
     XmlNodeList xNodeList; 
     if (xmlNode.HasChildNodes && xmlNode.Name != "title") //The current node has children 
     { 
      xNodeList = xmlNode.ChildNodes; 
      for (int x = 0; x <= xNodeList.Count - 1; x++) 
      //Loop through the child nodes 
      { 
       xNode = xmlNode.ChildNodes[x]; 
       //treeNode.Nodes.Add(new TreeNode(xNode.Name)); 
       //tNode = treeNode.Nodes[x]; 
       addTreeNode(xNode, treeNode); 
      } 
     } 
     else if (xmlNode.Name == "title") //No children, so add the outer xml (trimming off whitespace) 
      treeNode.Nodes.Add(new TreeNode(xmlNode.InnerText)); 
    } 

但是我必須強調，這是要達到的目標非常低效和不雅的方式。實際上，你可以做到這一點很簡單地使用XPath表達式象下面這樣：

OpenFileDialog dlg = new OpenFileDialog(); 
    dlg.Title = "Open XML document"; 
    dlg.Filter = "XML Files (*.xml)|*.xml"; 
    dlg.FileName = Application.StartupPath + "\\..\\..\\Sample.xml"; 
    if (dlg.ShowDialog() == DialogResult.OK) 
    { 
     try 
     { 
      //Just a good practice -- change the cursor to a 
      //wait cursor while the nodes populate 
      this.Cursor = Cursors.WaitCursor; 
      //First, we'll load the Xml document 
      XmlDocument xDoc = new XmlDocument(); 
      xDoc.Load(dlg.FileName); 
      //Now, clear out the treeview, 
      //and add the first (root) node 

      treeView1.Nodes.Clear(); 
      TreeNode rootTreeNode = new TreeNode(xDoc.DocumentElement.Name); 
      treeView1.Nodes.Add(rootTreeNode); 

      foreach (XmlNode titleNode in xDoc.DocumentElement.SelectNodes(@"//title")) 
      { 
       rootTreeNode.Nodes.Add(titleNode.InnerText); 
      } 

      treeView1.ExpandAll(); 
     } 
     catch (XmlException xExc) 
     //Exception is thrown is there is an error in the Xml 
     { 
      MessageBox.Show(xExc.Message); 
     } 
     catch (Exception ex) //General exception 
     { 
      MessageBox.Show(ex.Message); 
     } 
     finally 
     { 
      this.Cursor = Cursors.Default; //Change the cursor back 
     } 
    }}