Winforms树视图，递归检查子节点问题

问题描述

以下代码直接从Microsoft在。

The following code is taken direct from Microsoft at http://msdn.microsoft.com/en-us/library/system.windows.forms.treeview.aftercheck%28VS.80%29.aspx.

  // Updates all child tree nodes recursively.
  private void CheckAllChildNodes(TreeNode treeNode, bool nodeChecked)
  {
   foreach (TreeNode node in treeNode.Nodes)
   {
    node.Checked = nodeChecked;
    if (node.Nodes.Count > 0)
    {
     // If the current node has child nodes, call the CheckAllChildsNodes method recursively.
     this.CheckAllChildNodes(node, nodeChecked);
    }
   }
  }

  // NOTE   This code can be added to the BeforeCheck event handler instead of the AfterCheck event.
  // After a tree node's Checked property is changed, all its child nodes are updated to the same value.
  private void node_AfterCheck(object sender, TreeViewEventArgs e)
  {
   // The code only executes if the user caused the checked state to change.
   if (e.Action != TreeViewAction.Unknown)
   {
    if (e.Node.Nodes.Count > 0)
    {
     /* Calls the CheckAllChildNodes method, passing in the current
     Checked value of the TreeNode whose checked state changed. */
     this.CheckAllChildNodes(e.Node, e.Node.Checked);
    }
   }
  }

包含一个treeview并调用node_AfterCheck（惊喜，惊喜），树视图AfterCheck事件。然后，它递归检查或取消选中树视图上的子节点。

You put it in a form containing a treeview and call node_AfterCheck on (surprise, surprise), the treeview AfterCheck event. It then recursively checks or unchecks the child nodes on the treeview.

然而，如果你真的尝试了它，并且在同一个树视图复选框上多次点击，节点最终与其父检查不同步。你可能需要几个级别的孩子，可能有100个孩子，UI更新速度足够慢，可以注意到这种情况。

However if you actually try it, and click several times on the same treeview check box fast enough, the child nodes end up with their check out-of-sync with the parent. You probably need a couple of levels of children with perhaps 100 children in-total for the UI update to be slow enough to notice this happening.

我试过一对夫妇的事情（例如在node_AfterCheck开始时禁用treeview控件，并在结束时重新启用），但是不同步的问题仍然发生。

I've tried a couple of things (such as disabling the treeview control at the beginning of node_AfterCheck and re-enabling at the end), but the out-of-sync problem still happens.

Any

推荐答案

.NET TreeView类为原生Windows控件大量自定义鼠标处理，以合成Before / After事件。不幸的是，他们没有得到它很正确。当您开始快速点击时，您会生成双击讯息。原生控件通过切换项的选中状态来响应双击，不告诉.NET封装器。你不会得到一个Before / AfterCheck事件。

The .NET TreeView class heavily customizes mouse handling for the native Windows control in order to synthesize the Before/After events. Unfortunately, they didn't get it quite right. When you start clicking fast, you'll generate double-click messages. The native control responds to a double-click by toggling the checked state for the item, without telling the .NET wrapper about it. You won't get a Before/AfterCheck event.

这是一个错误，但他们不会修复它。解决方法并不困难，您需要防止本机控件看到双击事件。向项目中添加一个新类，并粘贴以下代码。编译。从工具箱顶部删除新控件，替换现有的控件。

It's a bug but they won't fix it. The workaround is not difficult, you'll need to prevent the native control from seeing the double-click event. Add a new class to your project and paste the code shown below. Compile. Drop the new control from the top of the toolbox, replacing the existing one.

using System;
using System.Windows.Forms;

class MyTreeView : TreeView {
    protected override void WndProc(ref Message m) {
        // Filter WM_LBUTTONDBLCLK
        if (m.Msg != 0x203) base.WndProc(ref m);
    }
}

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